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Glaucoma is the leading cause of irreversible blindness worldwide. The reconstruction of aqueous outflow drainage (RAOD) has recently been proposed to aid in restoring aqueous outflow drainage in primary open-angle glaucoma. However, the mechanism of RAOD remains to be fully understood. Based on literature review and research studies, the potential mechanisms of RAOD are the following: (i) Circumferential dilation of the Schlemm's canal (SC) and surrounding collector channels. (ii) Instant formation of microcracks through RAOD procedures. (iii) Formation of more pores, and local detachment between the SC endothelium (SCE) and basement membrane. (iv) Activation of stem cells by constant mechanical stress caused by the tensional suture placed at the anterior part of the SC. (v) Reversal of trabecular meshwork (TM) herniation. (vi) Mobilization of the reserve of the aqueous drainage. (vii) Change of SCE phenotype. (viii) Mechanosensing and mechanotransducing of TM.
Purpose: to present the mid-term results of canaloplasty in a small cohort of corticosteroid glaucoma patients.
Material and Methods: Nine eyes from seven patients with various types of corticosteroid glaucoma in maximum medical therapy underwent canaloplasty. Patients underwent complete ophthalmic examination every six months. Success was deﬁned as: post-operative intraocular pressure (IOP) ≤ 21 mmHg and ≤ 16 mmHg without (“complete success”), and with/without medical treatment (“qualiﬁed success”). The IOP reduction had to be ≥ 20. The number of medications before and after surgery was considered. The follow-up mean period was 32.7 ± 20.8 months (range 14–72 months).
Results: The pre-operative mean IOP was 30.7 ± 7.2 mmHg (range: 24–45). The mean IOP at 6 and 12-month follow-up was 13.1 ± 2.6 mmHg, and 13.7 ± 1.9 mmHg, respectively. Qualiﬁed and complete success at 6 and 12 months was 100% for both of the two deﬁnitions. The number of medications used preoperatively and at the 12-month follow-up was 4.3 ± 0.7, and 0.2 ± 1.0, respectively. No serious complication was observed.
Conclusions: The mid-term results of canaloplasty in patients with corticosteroid-induced glaucoma appear to be very promising. Canaloplasty should be considered as a possible alternative to ﬁltering surgery in this form of glaucoma, when medical therapy is not sufﬁcient to maintain the IOP within reasonable limits.
Purpose: To compare phacocanaloplasty (PC) and phaco-non-penetrating deep sclerectomy (PDS).
Methods: 75 patients with uncontrolled glaucoma and cataract were randomized for PC (37 eyes) or PDS (38 eyes). Intraocular pressure (IOP) and number of medications (meds) were prospectively evaluated. Follow-up examinations were performed on days 1 and 7 and after 1, 3, 6, 12, 18, and 24 months. Surgical success was calculated. Complications and postoperative interventions were noted. Quality of life (QoL) was analyzed.
Results: Preoperatively, mean IOP and meds were comparable (P >0 05). After 24 months, IOP signiﬁcantly decreased in PC from 19.4 ± 5.9 mmHg (2.6 ± 0.9 meds) to 13.8 ± 3.3 mmHg (0.5 ± 0.9 meds) and in PDS from 19.7 ± 5.4 mmHg (2.9 ± 0.9 meds) to 15.1 ± 2.9 mmHg (1.1 ± 1.2 meds). Statistically lower IOP was observed in PC in the 6th month and persisted until 24 months (P <0 05). No diﬀerence was found in meds (except for month 18, in which less drugs were used in PC (P =0 001)) or success rates (P >0 05). The most frequent complication in PC was transient hyphema (46%), in PDS bleb ﬁbrosis (24%). PC patients during postoperative period required only goniopuncture (22% of subjects), whereas PDS patients required, in order to maintain subconjuctival outﬂow, subconjunctival 5-ﬂuorouracil injections in 95% of cases (median = 3), suture lysis (34%), needling (24%), and goniopuncture (37%). NEI VFQ-25 mean composite score for PC was 78.04 ± 24.36 points and for PDS 74.29 ± 24.45 (P =0 136). α Cronbach’s correlation coeﬃcient was 0.913.
Conclusions: PC leads to a more eﬀective decrease in IOP than PDS in midterm observation with similar safety proﬁles. PDS patients required a vast number of additional procedures in contrast to PC patients, but this fact did not inﬂuence QoL.
To compare the effectiveness and safety of 120 applications versus 160 applications of selective laser trabeculoplasty (SLT) at reducing intraocular pressure (IOP) from baseline in glaucoma patients over a 1-year period.
A retrospective chart review was conducted, comprising 376 eyes from 199 patients who underwent SLT treatment performed by the same glaucoma subspecialist from 2014 to 2015. Data were obtained on patients' clinical features, management, and outcomes. Patients were treated with either 120 applications or 160 applications of SLT per 360 degrees of trabecular meshwork over 2 sessions. Statistical analyses were performed comparing baseline IOP with IOP at 6 weeks and 1-year follow-up after completion of treatment. The incidence and severity of transient IOP rises immediately post-SLT was also recorded.
Both SLT regimes were effective at reducing IOP. Univariate t tests showed that the 160 applications group had significantly greater mean reduction of IOP from baseline at both 6 weeks (4.6 vs. 3.6 mm Hg, P=0.015) and 1-year time points (4.1 vs. 2.8 mm Hg, P=0.019). However, when multivariate analyses were used to account for the effects of clustering and include other covariates such as age, baseline IOP, history of previous SLT there was no significant difference between success rates of the 2 treatment groups at either time points. Higher baseline IOP was associated with greater IOP reduction at 6 weeks (P<0.001) and 1 year (P<0.001) for both treatment groups. There was no statistical difference in incidence and severity of IOP spikes at 1-hour post-SLT between the 2 treatment groups.
SLT produces a significant IOP-lowering effect and treatment with 160 applications per 360 degrees may be more effective than 120 applications per 360 degrees. Furthermore, 160 applications of SLT does not increase the risk of transient IOP spikes.
Purpose: To report the incidence and management of haemorrhagic Descemet membrane detachment (HDMD) in canaloplasty and phacocanaloplasty.
Methods: This study included 105 eyes of 92 patients with uncontrolled open angle glaucoma who underwent canaloplasty and phacocanaloplasty between 2010 and 2014. Eyes that developed either HDMD or non-HDMD were identified. The main outcome measures were the development of HDMD and non-HDMD, best corrected visual acuity, recovery time after Descemet membrane detachment (DMD), intra-ocular pressure (IOP) and number of antiglaucoma medications. Each eye was managed according to the time of
development, type and extent of DMD.
Results: Ten eyes (9.5%) developed DMD-four eyes underwent canaloplasty (3.8%) and six eyes underwent phacocanaloplasty (5.7%). Three of 10 eyes developed non-HDMD while seven of 10 developed HDMD, the majority of HDMD cases occurred in combination with phacocanaloplasty (five of seven). The non-HDMD eyes resolved completely within 2 weeks without intervention. One eye with HDMD was observed for 2 weeks, before a 15% sulphur hexafluoride (SF6) intracameral injection was given. The patient developed a dense corneal stain that was resolving slowly over 30 months. One eye with HDMD underwent YAG laser membranotomy 2 weeks after being identified, which regained corneal transparency 1 month after treatment, while the remaining five eyes underwent immediate surgical drainage and regained corneal transparency 1 day post-procedure.
Conclusions: HDMD occurred in up to 6.7% in canaloplasty and phacocanaloplasty procedures, mostly during catheter withdrawal and the viscodilation step. Early recognition and management prevented further manipulation.
Purpose: Due to increasing cost pressure in the public health system treatments and their costs are highly relevant in the therapy for chronic diseases such as glaucoma. In the era of diagnosis-related group (DRG) reimbursement, new interventions need to prove not only their safety and effectiveness but also their cost-utility. Canaloplasty as a new interventional surgery is compared to trabeculectomy (TE) by means of a cost and effort analysis. Methods: In this retrospective, consecutive case series patients were compared as follows: group I, 21 eyes of 21 patients undergoing canaloplasty from 2009 on and group II, 48 eyes of 42 patients, who were treated with TE with mitomycin C (MMC) from 2001 to 2004 and had intensified postoperative care. Data regarding demography, duration of hospitalisation, duration of surgery, surgical complications and interventions, and pre- and post-operative IOP were analysed within the first 6 months post operation. Results: In group I mean duration of hospitalisation was 5.3 ± 0.8 days (d) and in group II 10.7 ± 2.8 d. Duration of surgery was 77 ± 14 min in group I and in group II 48 ± 11 min. On average 2.8 ± 1.0 visits were needed during follow-up in group I and 6 ± 1.5 visits in group II. The mean preoperative IOP of 28.75 ± 9.6 mmHg was lowered to 12.8 ± 3.3 mmHg after six months in group I and in group II from 34.5 ± 13.4 mmHg to 10.3 ± 4.5 mmHg. In group I, a total of 4 interventions were seen within the first six months without re-admission. In group II 107 interventions and eleven re-admissions were necessary. Mean costs for hospitalisation amount to 821.50 € in group I and 1658.50 € in group II. Overall expenses were 2379.62 € for canaloplasty and 2733.61 € for TE. Conclusion: Both interventions could effectively control IOP. However, trabeculectomy requires a longer hospitalisation, has higher re-admission rates and needs more frequent postoperative controls, which makes TE more costly and time-consuming than canaloplasty.
To analyze long-term structural changes in conjunctiva, sclera and Schlemm canal (SC) with anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) following uncomplicated canaloplasty.
Fifteen patients with planned canaloplasty and no intraoperative complications were included in this prospective study. AS-OCT images were acquired at 1, 3, 6 months and at a long-term time point (20±4.9 mo) postsurgery. UBM images were acquired at 3, 6 months and long-term after canaloplasty. The surgical site was evaluated for the presence of SC, transscleral filtration, a scleral lake, and the visibility of intra-Schlemm sutures. The SC's height and width were measured at the 3 and 9 o'clock limbus position.
Following canaloplasty, the intraocular pressure was successfully reduced from 23.43±5.52 to 12.6±1.78 mm Hg (P<0.0001) at the final control visit. Topical medication was reduced from 2.9±1.1 to 0.4±0.6 over the same period. SC's increase in height was higher than that in width at the last visit (height: +351%, P=0.0004, width: +144%, P=0.002). With the UBM the SC was easily identifiable by the reflection of the tractions sutures in 75% of the patients at the last visit. Transscleral filtration was detectable in 42% of the patients at the last visit using AS-OCT and a scleral lake was still detectable by OCT in 25% of the patients and even in 42% of the patients by UBM.
Persisting anatomic changes of SC, a transscleral filtration and a scleral lake can be recorded by AS-OCT and UBM long-term after successful canaloplasty.
Purpose: Canaloplasty (CP) is an important nonpenetrating surgery in treating open angle glaucoma. This system review studied the efficiency and the safety of CP and compared the differences of the outcomes between CP and trabeculectomy (TE) in glaucoma patients.
Methods: Literatures of CP were searched in PubMed and EMBASE without limitations of study types and languages. Meta-analysis was conducted of the postoperative reductions of intraocular pressure (IOP) and anti-glaucoma medications (AGMs) in CP and then of the differences in these reductions between CP and TE. Meta-analysis was also performed between CP and TE comparing the success rates and the incidence of the complications.
Results: 28 literatures were included in the system review of CP quantitatively, and 6 of them were enrolled in the meta-analysis comparing CP and TE. IOP decreased by 9.94 (95% CI 8.42 to 11.45) mm Hg with an average AGMs reduction of 2.11 (95% CI 1.80 to 2.42) one year after CP. The IOP reduction was significantly higher after TE than CP, with an average difference of 3.61 (95% CI 1.69 to 5.53) mm Hg at 12 months after surgery, while no significant differences were found in the AGMs decrease and the success rates between the two surgery methods. For complications, the incidence of hyphema was significantly higher in CP (OR 9.24, 95% CI 3.09 to 27.60) and the Descemet membrane detachment was just reported in CP, with an incidence of 3%. However, the incidence was significantly lower in CP of hypotony (OR 0.32 95% CI 0.13 to 0.80) and choroidal effusion/detachment (OR 0.25, 95% CI 0.06 to 0.97). Meanwhile, suprachoroidal hemorrhage and needling of bleb were only reported in TE, with an incidence of 2.3% and 10.9% respectively. No significant difference was found in the incidence of conjunctiva leakage between CP and TE (OR 0.72, 95% CI 0.16 to 3.14).
Conclusions: CP was less effective in IOP reduction than TE, but CP was able to achieve similar postoperative success rates and reduce the number of AGMs likewise. CP was also associated with lower incidence of complications and reported with higher patient satisfaction. More high quality researches, especially properly designed randomized controlled trials, are needed in the future to verify our findings in this system review.
To evaluate the efficacy and safety of gonioscopy-assisted transluminal trabeculotomy (GATT) in patients with open-angle glaucoma.
A retrospective chart review of adult patients who underwent GATT due to inadequately controlled intraocular pressure (IOP) or intolerance to medication. Main outcome measures were success rate, IOP, and number of glaucoma medications. Success was defined as IOP reduction >20% from baseline or IOP between 5 to 21 mm Hg, and no need for further glaucoma surgery. When success criteria were not met for any postoperative visit >3 months after surgery, failure was determined.
In total, 66 patients, average age 62.9±14.9 years (50.8% female) were included in the analysis. Average follow-up was 11.9 months (range, 3 to 30 mo) and overall success rate was 63.0%. Mean IOP was 26.1±9.9 mm Hg preoperatively and 14.6±4.7 mm Hg at 12 months (44% IOP decrease; P<0.001). Mean number of medications decreased from 3.1±1.1 preoperatively to 1.2±0.9 at 12 months (P<0.001). No significant differences between patients with primary open-angle glaucoma and other types of glaucoma were found.The rate of hyphema at 1 week and 1 month postoperatively was 38% and 6%, respectively. Overall GATT success rate among white and black patients was 69% and 42%, respectively, which was statistically significant (P<0.05).
The future of GATT as a minimally invasive glaucoma surgery in adults seems promising. This position is supported by its low rate of long-term complications and the conjunctiva-sparing nature of the surgery.
Purpose: The aim of this study was to evaluate the aqueous outflow system through channelography with fluorescein during non-penetrating glaucoma surgery (canaloplasty or phacocanaloplasty) and find correlations with preoperative and postoperative intraocular pressure (IOP).
Methods: Thirty-six patients (40 eyes) who had channelography while undergoing non-penetrating glaucoma surgery were included in this prospective study. Several parameters assessed during the channelography included: diffuse and superficial scleral staining, the number of visible superficial connections to collectors, trabecular permeability and number of micro-ruptures of the trabecular meshwork. IOP, the best-corrected visual acuity, the number of glaucoma medications was recorded at 1 day, 7 days, 3 months and 6 months after the operation.
Results: The change in IOP at 6 months from baseline significantly correlated with the number of visible superficial connections to collectors (r = 0.4, p = 0.021). Eyes with canaloplasty showed a mean baseline IOP of 19.4 (4.9) mmHg and mean glaucoma medication usage of 2.9 (1.0), which decreased to 13.2 (3.1) mmHg with 0.3 (0.8) medications, respectively, at 6 months postoperatively (p\0.001). Eyes with phacocanaloplasty surgery showed a mean baseline IOP of 28.2 (9.6) mmHg with 2.6 (0.9) mean drugs, which decreased to IOP of 12.8 (3.4) mmHg with 0.5 (0.8) medications at 6 months (p\0.001).
Conclusion: A larger number of defined visible superficial connections to collectors after injection of fluorescein into SC is related to a more pronounced IOP decrease after non-penetrating glaucoma surgery.
Purpose: The purpose of this study was to investigate the safety and efficacy of phacocanaloplasty with suprachoroidal drainage (PCscD) and to compare its intraocular pressure (IOP)-lowering and drug-sparing effect to canaloplasty with suprachoroidal drainage (CscD).
Methods: The study retrospective interventional study included patients with open-angle glaucoma or secondary forms of glaucoma who underwent either CscD or PCscD between the year 2011 and 2014 in Knappschaft Eye Clinic Sulzbach. Primary end-points were IOP reduction and the number of IOPlowering medication after 12 months. Secondary end-points were intraoperative and postoperative complications.
Results: A total of 328 eyes were included, 193 were treated with CscD and 135 underwent PCscD. Canaloplasty with scD achieved an IOP reduction of 37.0% (from 20.9 3.6 mmHg to 13.2 2.6 mmHg) after 1 year, whereas PCscD showed a significant higher reduction of 47.4% (from 23.2 5.1 mmHg to 12.2 1.7 mmHg). Reduction in IOP-lowering medication was higher after PCscD (from 3.6 0.6 to 0.2 0.5) than after CscD (from 3.5 0.8 to 0.7 1.0). Twelve months after surgery 55.5% in the CscD group and 80.2% in the PCscD group were free of IOP-lowering medication. In both groups, no severe or sight-threatening complications occurred.
Conclusion: Combining cataract surgery and CscD achieves a higher IOP reduction, and patients postoperatively need less IOP-lowering medication than after CscD alone.
Ab externo Schlemm's canal (SC) surgery (e.g., viscocanalostomy and canaloplasty) is a valuable alternative to glaucoma filtration surgery. It targets the abnormally high resistance to outflow in the trabecular meshwork (TM) and reestablishes the physiologic outflow system. In viscocanalostomy, viscoelastic substance is injected to dilate SC, which in turn leads to microdisruptions of the inner wall. In canaloplasty, the additional intracanalicular stent (suture or Stegmann Canal Expander®) keeps the canal patent and enhances the circumferential flow. A prerequisite for these procedures to work is the integrity of the distal outflow system, which can be evaluated by 2 clinical tests before surgery: provocative gonioscopy with blood reflux, and fluorescein channelography. Ab externo SC surgery is suitable for open-angle glaucoma, but also for angle closure glaucoma in combination with cataract extraction. Intraocular pressure reduction to the mid-teens for viscocanalostomy and to the lower-teens for canaloplasty can be expected. The majority of complications seen in filtering surgery are largely eliminated by the nonpenetrating and bleb-independent approach. Postoperative care is minimal as no bleb management such as needling is required, and hypotony-related complications are largely avoided by the intrinsic resistance of the physiologic outflow system. With its efficacy and high safety profile, ab externo SC surgery will continue to play an increasing role and will change the current concept of glaucoma surgery towards earlier intervention. Surgeons will be well advised to implement these antimetabolite-free procedures into their armamentarium to meet the expectations of the demanding glaucoma patient.
Purpose: To compare the outcomes of microcatheter-assisted circumferential trabeculotomy to standard rigid probe trabeculotomy in childhood glaucomas.
Methods: Eyes of children requiring trabeculotomy for primary congenital or secondary paediatric glaucoma were randomized to undergo either trabeculotomy using the Glaucolight illuminated microcatheter, or a rigid probe trabeculotomy. Complete success was defined as an intraocular pressure (IOP) of <18 mmHg without medications.
Results: A total of 62 eyes of 62 patients were included. Of these 30 eyes of 30 patients aged 5.6 4.8 months underwent microcatheter-assisted trabeculotomy, with 15 eyes (50%) having a complete 360° cut, while 15 eyes (50%) had an incomplete cut ranging from 250 to 350 degrees. The rigid probe trabeculotomy group included 32 eyes of 32 patients aged 4.4 3.8 months. At the end of the 2-year follow-up period, the complete success and the failure rates were 67% and 15%, respectively, in the microcatheter-assisted group versus 47% and 50% in the rigid probe trabeculotomy group (p = 0.006). There was a tendency towards lower IOP in the microcatheter group at 1, 3, 6, 12 and 24 months postoperatively, with the difference in IOP reaching statistical significance at 6 months (p = 0.004). The mean survival time was significantly longer for the microcatheter group (p = 0.01).
Conclusion: At 2 years postoperatively, microcatheter-assisted trabeculotomy still yielded superior results in terms of IOP control and success rates in children with primary congenital glaucoma. The need for reoperation for glaucoma was significantly lower in the microcatheter group.
Purpose: To report surgical outcomes of microcatheter-assisted trabeculotomy following failed angle surgeries, and compare those with no previous angle surgery, in primary congenital glaucoma (PCG).
Methods: The early postoperative (12 months) results of 42 eyes of 36 patients who underwent microcatheter-assisted trabeculotomy by single surgeon for PCG were retrospectively analyzed. Group 1, 20 eyes of 16 patients, had no previous angle surgery. Group 2, 22 eyes of 20 patients, had one or two previous failed angle surgeries. Success was defined as an intraocular pressure (IOP) o21mm Hg with at least a 30% reduction from preoperative IOP with (qualified success) or without (complete success) the use of antiglaucoma medication.
Results: Mean IOP decreased from 31.5±7.2 mm Hg on 3 (median, range: 1–5) medications in Group 1 and 34.6±7.3 mm Hg on 3 (median, range: 1–4) medications in Group 2 preoperatively to 15.6±3.1 mm Hg on 0 (median, range: 0–4) medications in Group 1 and 16.0±4.6 mm Hg on 0 (median, range: 0–2) medications in Group 2 postoperatively at 12 months (both Po0.001), respectively. The mean percentage of IOP reduction from preoperative to last postoperative visit was 46.0±20.1% in Group 1 and 45.5±25.0% in Group 2, P=0.947. Qualified and complete successes were comparable between Group 1 and Group 2 (qualified success: 90.0% vs 77.3%, P=0.294; complete success: 78.9% vs 77.3%, P=0.853). Complications were minimal.
Conclusions: Microcatheter-assisted trabeculotomy achieved significant pressurelowering effects with a reduction in medication use in PCG, and it represents a reasonable choice of initial and repeat surgical treatment for PCG.
Purpose: Description and evaluation of the technique and efficacy of canaloplasty ab interno (ABIC) in patients with open angle glaucoma (POAG).
Methods: In this monocentric series of consecutive cases, patients with cataract and open angle glaucoma (combined operation) and pseudophacic patients (mean age: 78 years, range 66-90 years), and suffering from POAG were included. All of them were operated with ABIC by using the iTrack™ 250 μ-microcatheter (Ellex Medical Lasers Pty Ltd, Adelaide, Australia), in order to circumferentially vasodilate Schlemm's canal without implanting a suture to increase tension. Primary endpoints were the mean IOP (intraocular pressure) after 1, 3, 6, 9 and 12 months surgery.
Results: Twenty-three patients (23 eyes) were included in the study. Mean IOP without a preoperative wash-out phase was reduced from 18.8 ± 5.63 mmHg preoperatively to 14.9 ± 2.90 mmHg (n = 22), 13.82 ± 2.98 (n = 19), 14.69 ± 2.36 mmHg (n = 13), 16.0 ± 2.09 (n = 11) and 14.73 ± 2.97 (n = 11) at 1, 3, 6, 9 and 12 months after surgery. Mean medication was reduced from 1.69 to 0.21 at the last follow-up. The only complication was limited descemetolysis near the limbus.
Conclusion: The initial results in this study indicate that ABIC reduces IOP and that the dependance on medication is comparable to that with ab externo canaloplasty.
Background: Trabeculectomy (TET) is still the most commonly performed surgical treatment in dealing with primary open angle glaucoma (POAG) worldwide. Canaloplasty (CP) as a nonpenetrating surgical procedure has recently become a new option to efficiently reduce intraocular pressure (IOP).
Objectives: This study compared both surgical procedures concerning the efficacy in IOP reduction. Furthermore we compared IOP fluctuation, postoperative medication, visual acuity, astigmatism and postoperative interventions and complications.
Materials and Methods: Retrospectively studied were 32 eyes after canaloplasty and 31 eyes after trabeculectomy. IOP, IOP fluctuation range, visual acuity, astigmatism and glaucoma medication were recorded preoperatively and after a follow-up of 6 and 12 months. In addition we compared postoperative complications and interventions of both surgical procedures.
Results: The mean IOP after canaloplasty was significantly reduced from 16.0 ± 3.5 mm Hg to 12.5 ± 3.3 mm Hg. Trabeculectomy also achieved a significant IOP reduction from 15.3 ± 3.5 mm Hg to 11.0 ± 2.6 mm Hg. Comparing the two surgical procedures there was no evidence for a significant difference in IOP reduction. Trabeculectomy was able to reduce the number of postoperative glaucoma medication substances better than canaloplasty. There was no difference in postoperative visual acuity or astigmatism. Concerning postoperative complications and interventions canaloplasty treatment was associated with a less severe spectrum of complications
Conclusion: Both procedures provide a safe and efficient IOP reduction. Trabeculectomy is able to achieve an even better IOP reduction without application of additional postoperative medication. Canaloplasty requires shorter inpatient stay, less frequent postoperative checkups and interventions as well as a less severe spectrum of complications.
The authors report a case of Descemet's detachment occuring during Canaloplasty performed after cataract extraction. A saline washout was performed and an air bubble was placed to aid reattachment. At final follow up, the patient achieved 20/20 uncorrected VA and 16mmHg IOP.
Purpose: To examine longer-term post-surgical safety and efficacy of a new expander for Schlemm’s canal.
Methods: In a non-comparative, prospective study, 42 White patients with medically uncontrolled primary open-angle glaucoma (POAG) underwent primary canaloplasty with >2-year follow-up. The bleb-independent procedure comprised catheter-assisted canaloplasty and implantation of two Stegmann Canal Expanders to maintain trabecular distension and canal patency over 180°. Intraocular pressure (IOP), glaucoma medication use and complications were assessed.
Results: Mean IOP was 26.8 5.6 mmHg pre-surgery, 12.8 1.5 mmHg at 6 months, 13.2 1.2 mmHg at 12 months and 13.3 2.5 mmHg at 24 months (p < 0.001). Rate of complete success, defined as IOP ≤21, ≤18 and ≤16 mmHg and a ≥ 30% IOP reduction, was 85% (95% CI: 0.76–0.95), 85% (0.76–0.95) and 82% (0.70–0.96) at 12 months and 83% (0.73–0.94), 80% (0.70–0.92) and 80% (0.70–0.92) at 24 months. Preoperative factors were not significant predictors of ≤16 mmHg IOP reduction: IOP (hazard ratio [HR]: 0.68; 95% CI: 0.44–1.04; p = 0.08), mean visual defect (1.06; 0.90–1.20; p = 0.47), number of medications (0.59; 0.17–2.14; p = 0.42) and age (0.96; 0.87–1.13; p = 0.41). Number of medications dropped from 2.8 0.4 pre-surgery to 0.2 0.5 post-surgery (p < 0.001). Mean preoperative best-corrected visual acuity was 0.19 SD 0.21 (range: 0–1.6), and logMAR was similar to 0.23 0.16 (range: 0–1.6; p = 0.42) after a mean follow-up of 27.4 months. Complications included peripheral Descemet’s membrane detachment (7.2%) and trimming of the expander (4.7%) during surgery, and transient microhyphaema (23.8%) and IOP elevation (7.2%) post-surgery.
Conclusion: Canaloplasty with the Stegmann Canal Expander was a safe and effective procedure to reduce IOP in White patients with moderate to advanced POAG.
We assessed the efficacy and safety of canaloplasty and trabeculectomy for treatment of glaucoma. We searched the China National Knowledge Infrastructure, PubMed, Web of Science, and WanFang databases for potential eligible studies. Pooled risk ratio (RR) with 95% confidence interval (CI) was calculated using random or fixed-effect models if appropriate. Eight studies were included for meta-analysis. There was no difference in intraocular pressure at 6 months (WMD = 0.97, 95%CI: -0.48-2.41). Intraocular pressure in canaloplasty group 12 months after operation was higher than in trabeculectomy group (WMD = 1.90, 95%CI: 0.12-3.69), P < 0.05). The canaloplasty group showed higher success rate than trabeculectomy group (RR = 0.86, 95%CI: 0.77-0.97). The canaloplasty group was more likely to have hyphema (RR = 2.96, 95%CI: 1.51-5.83), P < 0.05) than trabeculectomy group (RR = 0.24, 95, CI(0.06-0.89), P < 0.05]. The incidence of and hypotony and post-operative choroid abnormalities in canaloplasty group was significantly lower than that in trabeculectomy group (RR = 0.30, 95%CI: 0.11-0.83; RR = 0.24, 95%CI: 0.09-0.66), P < 0.05). Both trabeculectomy and canaloplasty can significantly reduce the intraocular pressure in glaucoma patients at 12 months after operation, trabeculectomy leads a more marked IOP decrease than canaloplasty at the cost of a higher complication rate and more demanding for postoperative care.
Aims: To determine the influence of prostaglandin analogues (PGAs) on corneal biomechanical properties in patients undergoing chronic treatment for primary openangle
Methods: Prospective, interventional case–control study. 70 eyes from 35 patients with POAG on chronic PGA therapy were recruited. One eye per patient underwent PGA cessation for 6 weeks while the contralateral eye continued to receive the treatment. Corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOP) (IOPcc), central corneal thickness (CCT) and Goldmann tonometry (Haag-Streit AG, Koeniz, Switzerland) IOP (IOPGAT) were measured at baseline (visit 1), 6 weeks after PGA cessation (visit 2) and 6 weeks after PGAs reinitiation (visit 3) and were analysed using a linear mixed-effect model. The discrepancy between IOPcc and IOPGAT was defined as IOP bias (IOPcc—IOPGAT).
Results: Baseline characteristics were comparable between the two groups. In the study eyes, significant increases (p<0.0001) were detected at visit 2 in CH (9.0±1.8 vs 10.3±1.7 mm Hg), CRF (10.5±2.1 vs 11.7 ±2.1 mm Hg), CCT (541.8±43.2 vs 551.9±41.9 μm) and IOPGAT (15.4±3.0 vs 18.4±3.8 mm Hg). IOP bias in this group was significantly lowered at visit 2 (p<0.0001). These effects were reversed at visit 3. The control eyes did not demonstrate any significant changes over the study period.
Conclusion: Topical PGAs induce reversible reduction in CH, CRF and CCT in patients with POAG. These changes contribute to underestimation of the IOP meas
Introduction: The purpose of this study was to compare the efficacy and safety of canaloplasty versus viscocanalostomy in management of uncontrolled primary open angle glaucoma (POAG) with medication.
Methods: Canaloplasty surgery was applied for thirty eyes of thirty patients (45- 55 years) with a mean age of 48 years (Group A) and viscocanalostomy surgery was applied also for thirty eyes of thirty patients (43- 54 years) with a mean age of 46 years (group B). All patients were with uncontrolled primary open angle glaucoma by maximally tolerated medical therapy.
Results: Intraocular pressure (IOP) in both surgeries was significantly reduced through follow up period (p < 0.0.001). Complete success was 86.6% in group A and 80% in group B. Visual field deterioration was in 2 cases (6%) in group A and in 4 cases (13%) in group B. Low incidence of postoperative complications was reported as Descemet’s membrane detachment (3% in group A and 8% in group B), ocular hypotony (2% in group A and 4% in group B) and hyphema (3% in group A and 5% in group B).
Conclusion: Canaloplasty was more effective and safer than viscocanalostomy in management of uncontrolled primary open angle glaucoma (POAG) with medication.
Purpose: While angle surgeries show good success in primary congenital glaucoma reported success in glaucoma following cataract surgery (GFCS) and juvenile open angle glaucoma (JOAG) is variable and with relatively short follow-up. We evaluated longer-term outcomes of 360-trabeculotomy for medically-refractory GFCS and JOAG.
Design: Retrospective case series.
Methods: First operated eyes of consecutive patients with medically-refractory GFCS and JOAG in a single-surgeon pediatric glaucoma practice who underwent illuminated microcatheter-assisted 360-trabeculotomy from 2/2008-6/2015 were reviewed. Baseline characteristics, time to failure or last visit, surgical details, final intraocular pressure (IOP), and complications were recorded. Success required IOP≤22mmHg and 20% reduction without additional glaucoma surgery or devastating complication.
Results: Thirty-five eyes (35 patients) were included: 25 GFCS and 10 JOAG (mean age at surgery 5.6 vs. 16.7 years, respectively, p<0.001). Success for GFCS and JOAG was 18/25 (72%) versus 6/10 (60%) eyes at mean f/u 31.9±26.1 versus 24.5±19.7 months, respectively. IOP was significantly reduced from baseline for both GFCS and JOAG (31.5±7.5 vs. 19.2±7.7 mmHg, p<0.001; and 29.5±10.3 vs. 15.8±6.6, p<0.001, respectively). Fewer glaucoma medications were needed after surgery (p=0.01) for GFCS but not JOAG. Complications (all but two spontaneously resolving) included: choroidal effusion (1), vitreous hemorrhage (3), Descemet detachment (1) and persistent hyphema (2). Three-year Kaplan-Meier success for GFCS vs. JOAG was 75.3% vs. 53.3%, respectively.
Conclusions: Illuminated micro-catheter assisted 360-trabeculotomy is a useful, low-risk, modestly successful initial surgical treatment for both medically refractory GFCS and JOAG
Aim: To evaluate the advantage of canaloplasty compared to trabeculectomy for patients with open angle glaucoma.
Methods: Potentially relevant studies were systematically searched using various databases from inception until December 2015. The outcome analyses performed automatically using Revman 5.3 included intraocular pressure reduction (IOPR), postoperative success rate, anti -glaucoma medications reduction and the incidence of adverse events.
Results: We included four qualified studies incorporating a total of 215 eyes for quantitative synthesis. The weighted mean difference (WMD) of IOPR between canaloplasty and trabeculectomy from baseline to 12mo was -2.33 (95%CI: -4.00, -0.66). There was not significant improvement in the complete or qualified success rate (OR:0.58, 95% CI:0.26, 1.31; OR:0.50, 95% CI:0.10, 2.44, respectively). Similarly, no statistically significance was observed in anti-glaucoma mediations reduction (WMD:-0.54, 95% CI:-1.18, 0.09). Sensitivity analysis of the primary outcome estimate confirmed the stability of the Meta-analysis result.
Conclusion: Trabeculectomy seems to be more effective in lowering IOP up to 12mo when comparing with canaloplasty. Canaloplasty does not seem to be inferior to trabeculectomy considering the postoperative success rate or the number of postoperative anti-glaucoma medications. Meanwhile, it has an advantage of less bleb related complications.
Background/Aims: This study was to explore the 1-year interim efficacy and safety of canaloplasty for primary open-angle glaucoma (POAG) with failed glaucoma filtration surgery (GFS) but an intact Schlemm’s canal (SC).
Methods: This was a single-surgeon prospective clinical study. Patients with POAG scheduled for canaloplasty were included and divided into two groups (with or without failed GFS). The status of SC was determined by gonioscopy and ultrasound biomicroscopy. Primary outcome measures included intraocular pressure (IOP) and glaucoma medication use at various follow-up points. The secondary outcome measure was the rate of surgical success.
Results: Thirty-seven eyes were enrolled in group 1 (no GFS) and 23 eyes were enrolled in group 2 (failed GFS). The mean IOP (16.0 ± 1.6 vs 16.2 ± 1.6 mm Hg) and the number of medications (0.3 ± 0.8 vs 0.3 ± 0.6) at 18 months after canaloplasty were not significantly different between the two groups. There was no significant difference in complete success rate (criteria A: 52.2% vs 59.5%, p=0.587; criteria B: 39.1% vs 48.6%, p=0.343), as well as the qualified success rate (criteria A: 86.5% vs 82.6%, p=0.668; criteria B: 78.4% vs 69.6%, p=0.445). In group 2, the age, sex, number of previous surgeries, time span between operations were not significantly associated with surgery failure ( p=0.199, 0.747, 0.977 and 0.615). Hyphaema was the most common postoperative complications.
Conclusions: Canaloplasty is an effective and safe option for POAG with failed GFS but an intact SC.
Purpose: To report on outcomes of gonioscopy-assisted transluminal trabeculotomy (GATT) in eyes with prior incisional glaucoma surgery.
Patients and Methods: A retrospective review was performed for all patients who underwent a GATT procedure with a history of prior incisional glaucoma surgery.
Results: Thirty-five eyes of 35 patients were treated. The mean age was 67.7 years. Nineteen eyes had a prior trabeculectomy, 13 eyes had a prior glaucoma drainage device, 4 eyes had a prior trabectome, and 5 eyes had prior endocyclophotocoagulation. Mean follow-up time was 22.7 months. For all eyes, the mean preoperative intraocular pressure (IOP) (SD) was 25.7 (6.5)mm Hg on 3.2 (1.0) glaucoma medications and at 24 months, the mean IOP (SD) was 15.4 (4.9) mm Hg on 2.0 (1.4) glaucoma medications (P<0.001). The prior trabeculectomy group had a preoperative IOP (SD) of 24.6 (6.4)mm Hg on 3.2 (1.0) medications and at month 24, the mean IOP (SD) was 16.7 (5.6) mm Hg on 2.1 (1.4) glaucoma medications. In the prior glaucoma drainage device group, the mean preoperative IOP (SD) was 27.0 (7.1)mm Hg on 3.4 (1.1) glaucoma medications and at 24 months, the mean IOP (SD) was 12.9 (2.6)mm Hg on 2.1 (1.2) glaucoma medications. At 24 months, the cumulative proportion of failure was 0.4 and the cumulative proportion of reoperation was 0.29.
Conclusions: GATT appears to be safe and successful in treating 60% to 70% of open-angle patients with prior incisional glaucoma surgery. When considering all eyes, there was a significant decrease in IOP and required glaucoma medications at 24 months. This surgery should be considered in certain patients with open angleswho have failed a primary traditional glaucoma surgery.
Abstract: Fiberoptic microcatheter-assisted 360-degree trabeculotomy ab externo is a recent technique. Retrospective studies have proved the effectiveness as a first-angle surgery in eyes with primary congenital glaucoma. However, there are no reports in which it is performed after another unsuccessful surgical procedure. We present our case of a monolateral congenital glaucoma. We first performed an ab externo trabeculotomy with poor control of intraocular pressure (IOP). Then, a microcatheter-assisted 360- degree trabeculotomy was performed with IOP lowering. Microcatheter-assisted 360-degree trabeculotomy supplies successful IOP lowering after another angle surgery procedure.
The paper presents a case of a pseudoexfoliative glaucoma previously treated with argon laser trabeculoplasty in a tertiary center, who was scheduled for canaloplasty in the Ophthalmology Department of the County Hospital Piatra Neamt, Romania. Although the status post laser trabeculoplasty is not among the best indications for canaloplasty, the article confirms the fact that this procedure can also be successfully performed in these cases.
Purpose: To compare microcatheter-assisted trabeculotomy with standard rigid probe trabeculotomy for the treatment of childhood glaucoma.
Methods: The early postoperative (12 months) results of microcatheter-assisted trabeculotomy (group 1) performed by single surgeon were retrospectively compared with those of rigid probe trabeculotomy (group 2) performed by the same surgeon in patients treated for childhood glaucoma. Success was defined as an intraocular pressure (IOP) <21 mm Hg with at least a 30% reduction from preoperative IOP with (qualified success) or without (complete success) the use of antiglaucoma medication.
Results: A total of 43 eyes of 36 patients were included. Mean IOP in group 1 was significantly lower than that in group 2 at 6 months (17.0±5.1 vs 22.5±9.8; p=0.042), 9 months (16.3±5.0 vs 21.6±9.6; p=0.009) and 12 months (14.8±2.5 vs 19.0±7.1; p=0.049) postoperatively. The mean percentage reduction in IOP from preoperative to the last postoperative follow-up was greater in group 1 (47.3±17.7%) than in group 2 (34.2±21.9%) (p=0.036). Group 1 demonstrated an 81.0% complete and 86.4% qualified success rate, exceeding the 51.6% complete (p=0.060) and 61.9% qualified (p=0.037) success rate of group 2. There were no long-term complications in either group, but choroidal detachment occurred in one eye in group 2.
Conclusions: Microcatheter-assisted circumferential trabeculotomy is a more effective treatment and is as safe as traditional trabeculotomy with a rigid probe for primary congenital glaucoma in the early postoperative course.
Purpose: To evaluate the in vivo changes in the Schlemm’s canal (SC) and the trabecular meshwork (TM) in patients with primary open-angle glaucoma (POAG) after phacocanaloplasty using anterior segment optical coherence tomography (AS-OCT).
Methods: Ten eyes of nine patients with POAG (6 men, 3 female) who underwent phacocanaloplasty. Preoperative and postoperative visual acuity (VA), intraocular pressure (IOP) and use of glaucoma medications were evaluated. The main outcome measures were the area of SC and TM thickness assessed using AS-OCT before and 12 months after surgery.
Results: We found statistically significant reduction in IOP (from 26.4 (8.6) mmHg to 12.9 (2.5) (p<0.05) mmHg, increase in VA from 0.7 (0.4) to 0.9 (0.2) and decrease in glaucoma medication from 2.6 (1.2) to 1.1 (1.3) at 12 months postoperatively. There was a significant increase in the SC area (3081.7 (842.8) μm² vs. 5098.8 (1190.5) μm², (p<0.001) and a decrease in mean TM thickness (91.2 (18.6) μm vs. 81.3 (15.1) μm, p=0.001) after surgery. We found negative correlations between SC area and IOP before surgery (r=-0.67, p=0.03) also between SC area before and IOP reduction 12 months after the phacocanaloplasty (r=-0.80, p=0.005).
Conclusions: Our results showed statistically significant dilation of SC area and reduction of TM thickness after phacocanaloplasty in POAG patients. The degree of SC expansion was related to the IOP decrease.
Canaloplasty is a recently introduced non-penetrating surgical technique for glaucoma, which seeks to improve the natural outflow of aqueous humor through Schlemm’s canal and the collector channels. Just as in all forms of glaucoma surgery there are a certain number of failures of the procedure and further surgery is often needed to reduce the intraocular pressure in these cases. This article describes some of the revision procedures after canaloplasty.
Canaloplasty is a nonpenetrating blebless surgical technique for open-angle glaucoma, in which a flexible microcatheter is inserted within Schlemm’s canal for the entire 360 degrees. When the microcatheter exits the opposite end, a 10-0 prolene suture is tied and it is then withdrawn, by pulling microcatheter back through the canal in the opposite direction. Ligation of prolene suture provides tension on the canal and facilitates aqueous outflow.The main advantage of canaloplasty is that this technique avoids the major complications of fistulating surgery related to blebs and hypotony. Currently, canaloplasty is performed in glaucoma patients with early to moderate disease and combination with cataract surgery is a suitable option in patients with clinically significant lens opacities.
Purpose: The aim of this study was to investigate the efficacy and safety of a new and modified canaloplasty technique with suprachoroidal drainage in a large patient cohort, and to compare its IOP-lowering and topical drug-sparing effect to that of conventional canaloplasty.
Methods: This retrospective clinical trial included patients with open-angle glaucoma or secondary forms of glaucoma who underwent either conventional canaloplasty or canaloplasty with suprachoroidal drainage. Primary endpoint was the IOP reduction after 12 months as well as the number of IOP-lowering medications. Secondary endpoints were intra- and postoperative complications and the occurrence of secondary surgical interventions.
Results: Four hundred and seventeen eyes were included in the study; 180 of them were treated with conventional canaloplasty, and 237 eyes underwent canaloplasty with suprachoroidal drainage. In both groups, a significant IOP reduction could be observed after 12 months. Mean IOP reduction was stronger after canaloplasty with suprachoroidal drainage (35.9 %) (from baseline 20.9± 3.5 mmHg to 13.1 ± 2.5 mmHg) than after conventional canaloplasty (31.2 %) (from baseline 20.8 ± 3.6 mmHg to 14.0 ± 2.6 mmHg) (p < 0.01). The number of IOP-lowering medications decreased significantly in both groups: after canaloplasty with suprachoroidal drainage from 3.5 ± 0.9 to 0.7 ± 1.0, and after conventional canaloplasty from 3.4 ± 0.9 to 0.8 ± 0.9 with different drugs. The percentage of patients who were free of IOPlowering agents after 1 year was significantly higher in the combined group (56.9 %) than in the group of conventional canaloplasty (45.4 %) (p= 0.0383). No serious complications were observed.
Conclusions: The modified surgery technique of canaloplasty with suprachoroidal drainage yields the opportunity to optimize the IOP-lowering effect of canaloplasty as a nonpenetrating surgical procedure while still offering a more favourable safety profile than trabeculectomy. The suprachoroidal access facilitates the most complicated step of the canaloplasty surgery: the localization of Schlemm’s canal.
The authors of the article comparing the results of traditional canaloplasty with modified canaloplasty (opening up the sub-choroidal pathway) compliment Mattlach et al on their article "Trabeculectomy versus canaloplasty (TVC) in the treatment of patients with OAG" and only wish they had been less "subtle" in their statements. In the view of this team, CP is first-line strategy yielding the same IOP-lowerng potential with less severe side-effects that trabeculectomy and more attractive post-op strategies.
The aim of this study has been to visualize the aqueous outflow system in patients affected by primary open angle glaucoma. A solution of indocyanine green (ICG) plus high viscosity viscoelastic solution was injected into the Schlemm canal during surgery in 10 glaucomatous patients undergoing canaloplasty. Soon after injection of the dye the borders of the scleral flap were completely stained due to partial reflux caused by the intrachannel resistance; progression of the dye along the Schlemm canal starting from the site of injection was then visualized. The filling of the collector channels was observed only in the patent portions of the Schlemm canal. The only noticeable aqueous veins were located in correspondence of the quadrant in which both the Schlemm canal and the collectors were patent. Lastly, a retrograde filling, of glomerular-shaped structures, deepest to the Schlemm canal was observed in the quadrants where the pathway was functioning. Our findings show that injection of a mixture composed of ICG and viscoelastic solution into the Schlemm canal allows a clear visualization of the functioning portions of the conventional outflow pathway. In addition, a retrograde filling of structures presumably located into the iris was also recorded.
Purpose: We investigated whether 24-hour monitoring of corneoscleral limbus area (CSLA) with the Sensimed Triggerfish contact lens sensor (CLS) can be used clinically to assess midterm efficacy of canaloplasty and to assess the relationships of CSLA changes with the heart rhythm.
Methods: Ten eyes of 10 patients, with POAG, which were qualified either to canaloplasty or canaloplasty and phacoemulsification, were included in this study. Eyes were washed out before the surgery and control visits were done at days 1, 7, and 3, 6, 12 months postoperatively, at which subjects were examined. We performed 24-hour monitoring of CSLA changes and Holter ECG at washout, and at 3- and 12-month postop visits. Raw CLS signals were processed to lead two parameters describing short-term 24-hour variability of CSLA (VAR, ˆa). Heart activity parameters from CLS were compared to those acquired from Holter ECG.
Results: Mean post washout IOP was 20.6 6 4.7 and decreased to 14.2 6 3.0 mm Hg 1 year after surgery (P < 0.01). A decreasing trend in VAR and ˆa parameters were noted. Statistically significant differences were found between the washout and 3-month postop visit for VAR and ˆa (P ¼ 0.014 and P ¼ 0.027, respectively) as well as between the washout and 12-month postop result for the parameter ˆa (P ¼ 0.031). No statistically significant differences were found between the 3- and 12-month postop results for both considered parameters.
Conclusions: Canaloplasty alone or combined with cataract surgery is a successful surgical method of lowering IOP in glaucoma patients. Canaloplasty decreases 24-hour CSLA fluctuation pattern measured with CLS.
Purpose: We describe a modified canaloplasty technique and report the short-term efficacy for primary open-angle glaucoma (POAG) patients with disruption of Schlemm canal (SC) wall resulting from prior glaucoma surgery.
Patients and Methods: This was a single-surgeon prospective cohort study. POAG patients scheduled for canaloplasty were included and divided into 2 groups: group1 included POAG patients without a history of glaucoma surgery and group 2 included POAG patients with failed glaucoma surgery and disrupted SC. The status of SC was determined by gonioscopy and ultrasound biomicroscopy.
Standard canaloplasty procedures were performed in group
1. A modified canaloplasty technique was used in group 2. Primary outcome measures included the intraocular pressure and glaucoma medication use at various follow-up points.
Results: Seventeen patients were enrolled in group 1 and 9 patients were enrolled in group 2. At the 12-month follow-up, there was no significant difference between groups 1 and 2 (17.8±2.7 vs. 16.7±2.4mm Hg, respectively; P=0.362) and in the mean number of medications (0.9±1.2 vs. 0.3±0.5, respectively; P=0.061). In both groups, at all follow-up points, the intraocular pressure and the mean glaucoma medication usage had decreased significantly compared with measurements at baseline (P<0.001).
The rate for successful circumferential catheterization was not significant between the 2 groups (88.2% vs. 77.8%, P=0.063).
Conclusion: Modified canaloplasty is a feasible, safe, and potentially effective option for patients with POAG and regions of SC disruption resulting from previous glaucoma-filtering surgery.
In 1893, De Vicentiis first described surgery of the iridocorneal angle in patients with congenital glaucoma. Goniotomy followed in the 1940s, described by Barkan.12,13 Since then procedures involving the iridocorneal angle have continued to emerge, from laser trabeculopuncture, to goniocurretage, to the Trabectome microelectrocautery device (NeoMedix Corp. San Juan Capistrano, California) and the trabecular microbypass stent (Glaukos Corp., Laguna Hills, California). Ab externo approaches to Schlemm’s canal have also been developed such as the nonpenetrating canaloplasty using the iScience microcatheter device (iScience Interventional Inc., Menlo Park, California). This chapter reviews the various new surgical devices except for the trabecular micro-bypass stent (Glaukos Corp., Laguna Hills, California), which is discussed in another chapter.
Non-penetrating Schlemm's canaloplasty and MMC trabeculectomy were found to have equal efficacy with regards to IOP lowering and decrease in glaucoma medication usage at up to 1 year postoperatively. Eyes undergoing canaloplasty recovered BCVA faster postoperatively than eyes undergoing trabeculectomy. Eyes undergoing canaloplasty sustained fewer complications than those undergoing trabeculectomy.
Purpose Glaucoma is a common vision-threatening complication of uveitis.We investigated the outcome of canaloplasty
in patients with chronic uveitis and uncontrolled secondary glaucoma.
Methods: This was a retrospective study of 12 patients with medically uncontrolled secondary glaucoma who underwent
canaloplasty (14 treated eyes), with follow-up of ≥ 24 months. The primary outcome measure was complete and qualified (requirement for anti-glaucomatous medication) surgical success rates, as determined by a reduction in intraocular pressure
(IOP) and the need for anti-glaucomatous medication. Secondary outcome measures were uveitis activity, bestcorrected
visual acuity (BCVA), vision-threatening complications, and secondary glaucoma surgery.
Results Canaloplasty resulted in a significant IOP reduction, from a mean preoperative baseline level of 27.1± 12.3 mmHg
to a mean of 14.5 ± 4.3 mmHg (p = 0.01) at 24 months. Complete success (limit of 15 mmHg) was achieved in six patients and qualified success in one patient. However, failure was noted in five patients, two of whom required additional
glaucoma surgery. Topical anti-glaucomatous medications were reduced from 2.7 ± 1.2 (mean ± SD) at baseline to 0.6 ± 1.2 at 24 months (p =0.007). Uveitis activity did not increase after surgery. BCVA was not reduced; cataract progressed in two patients.
Conclusion At 2-year follow-up, overall success rate was 58 % (IOP ≤ 15 with or without medication), and surgery failed in 5 eyes, 2 eyes requiring additional glaucoma surgery. No harmful complications or worsening of uveitis activity were noted.
Purpose: To compare outcomes of phaco-canaloplasty (PC) and phaco-non-penetrating deep sclerectomy (PDS) with a viscoelastic compound.
Methods: This study included 29 eyes after PC and 30 after PDS. Indications were uncontrolled primary open-angle glaucoma (POAG) and a cataract. Corrected distance visual acuity (CDVA), intraocular pressure (IOP), and number of medications were evaluated. Follow-up examinations were performed on days 1 and 7, and after 1, 3, 6, and 12 months. Complete and qualified success was an IOP ≤ 18 mmHg.
Results: At the 12-month follow-up, mean IOP decreased in the PC group from 19.0±6.9 mmHg to 12.6±2.7 mmHg, and in the PDS group, from 19.1±5.8 mmHg to 14.3±3.5 mmHg (P<0.05). Both groups preoperatively and at 12 months showed no significant differences in IOP (P>0.05). There was no statistically significant difference between the number of medications used (P>0.05). Complete and qualified success rates for both groups were 79.0%and 76.9%(P=0.701). The most frequent postoperative PC complication was hyphema (58.0 %); for PDS, bleb fibrosis was most frequent (26.7 %). No PC patients required postoperative management. PDS patients required postoperative interventions 58.7 % of the time, including a 5-fluorouracil (5-FU) injection (58.7 %), suture lysis (48.3 %), and needling (27.6 %).
Conclusions: Both PC and PDS lead to an effective decrease in IOP on a short-term follow-up basis and demonstrate similar efficacy and safety profiles. PDS patients required additional procedures including 5-FU injections, suture lysis, or needling. PC patients required no additional procedures.
Purpose: To describe a case of hemorrhagic Descemet membrane detachment after canaloplasty and to discuss its management using alteplase, a tissue plasminogen activator (TPA).
Methods: Interventional case report.
Results: A 60-year-old woman with advanced pseudoexfoliation glaucoma developed severe hemorrhagic Descemet detachment after canaloplasty. Initial anterior chamber and pre-Descemet washout yielded no improvement. On the fifth postoperative day, the patient received a novel pre-Descemet treatment using a TPA with an anterior chamber air bubble. The intracorneal blood clot quickly dissolved intraoperatively with the Descemet membrane almost completely reattached on postoperative day 1.
Conclusions: Hemorrhagic Descemet detachment is a rare and serious complication of canaloplasty. The use of pre-Descemet TPA dissolves the intracorneal blood clot and helps reattach Descemet membrane, allowing quick rehabilitation of patient’s vision and
preserving integrity of the cornea.
Purpose: Purpose The role of canaloplasty has been relegated to primary glaucoma procedures in the past. This study sought to evaluate whether canaloplasty could be performed in cases failing previous surgery and if a retentive stent was essential for a successful outcome. Methods A retrospective review of 23 consecutive patients, average age 65.5 years, 60.9% female undergoing canaloplasty from April 2012 was conducted. All patients failed previous surgeries including ALT, SLT, Trabeculectomy w/Mitomycin and aqueous shunting alone or in various combinations. Only one eye from bilateral patients was randomly selected to be included in the analysis. Parameters monitored measured included VA, IOP, visual field, nerve fiber layer analysis, and number of medications which were compared with and without stent. The relationship between the change in number of medications and improvement of IOP was also explored using correlation analysis. Results Retentive stent was used in 52.2% eyes. Both groups demonstrated significant reduction in number of medications,with or without stents, mean reduction (standard deviation) 1.3 (1.7) (p-value = 0.024) and 1.7 (0.8) (p-value < 0.001), respectively. Significant IOP improvement was observed in stent group: mean (standard deviation) 4.8 (5.7) (p-value = 0.013). None of the outcomes evaluated were found to be statistically different between these two groups. Improvement of IOP and medication reduction indicates a negative correlation (Spearman's rho = -0.553) for non-stent group, whereas the correlation was positive (Spearman's rho = 0.123) for stent group, although not statistically significant. Conclusion Canaloplasty appears to represent a viable option for control of glaucoma, despite previous failed glaucoma surgeries, therefore expanding treatment paradigm options. All parameters measured showed improvements in both groups. Larger clinical trials are needed to further investigate stent's value in this setting.
Purpose: To describe a case of hemorrhagic Descemet membrane detachment following canaloplasty and discuss its management using alteplase, a tissue plasminogen activator. Methods Interventional case report. Results A 60-year-old woman with advanced pseudoexfoliation glaucoma developed a severe hemorrhagic descemet detachment after canaloplasty. Initial anterior chamber and pre-descemet washout yielded no improvement. On the 5 th post operative day, the patient received a novel pre-descemet treatment using a tissue plasminogen activator with an anterior chamber air bubble. The intracorneal blood cloth quickly dissolved intraoperatively with the descemet membrane almost completely reattached on post operative day 1. Conclusion Hemorrhagic descemet detachment is a rare and morbid complication of canaloplasty. The use of pre-descemet tissue plasimogen activator dissolves the intracorneal blood cloth and helps reattach descemet’s membrane, allowing a quick rehabilitation of the patient vision and preserving the integrity of his cornea.
This study was performed to assess any changes in Schlemm’s canal (SC) in human autopsy eyes possibly resulting from the injection of a viscoelastic substance and implantation of a new device (the Stegmann Canal Expander, SCE) into SC. After the surgical procedure, eyes were fixed, dissected into quartered segments and
examined using light and scanning electron microscopy. Tissue sections displayed a marked dilation of SC and of the collector channels compared with untreated control sections. The SC walls were disrupted in some areas due to viscodilation, but not due to SCE implantation. In all eyes, the entire 9-mm length of the SCE was positioned inside the canal, keeping the canal wide open. The SCE diameter of 240 μm remained unchanged after implantation. Injection of a viscoelastic substance into SC leads to marked dilation of SC and collector channels. Implanting the SCE into SC allowed persistent expansion of SC and stretching of the trabecular meshwork. This may increase the permeability of the
trabecular meshwork, reduce its resistance to aqueous humour and maintain circumferential flow within SC. Experimental and clinical studies should determine the
impact of this new canal expander in terms of lowering intraocular pressure in glaucoma surgery
Purpose: To compare operative outcomes of patients after phacocanaloplasty and phacotrabeculectomy through 12 months’ followup.
Design: Retrospective, nonrandomized, comparative case series.
Materials and Methods: We included 36 eyes of 36 patients with open-angle glaucoma who underwent combined phacoemulsification and canaloplasty (phacocanaloplasty) and 41 eyes of 41 patients with open-angle glaucoma who underwent combined phacoemulsification and trabeculectomy with mitomycin C (phacotrabeculectomy) with 12 months’ of postoperative follow-up. All surgeries were performed by a single surgeon (R.S.A.) between January 2007 and May 2011.
Main Outcome Measures: Failure was based on intraocular pressure (IOP; >18 or <4mm Hg at 1 y), second operative procedure (any eye requiring reoperation), or decrease in visual acuity by 0.20 logMAR. Change in IOP, visual acuity (VA), glaucoma medications, and complication rates at 12 months were analyzed.
Results: There were no differences in demographics other than the sex between the groups. There were also no significant differences in previous surgery or in preoperative VA, IOP, or use of glaucoma medications between the groups, though the phacotrabeculectomy group had a higher preoperative IOP at baseline and a larger SD. Both groups showed significant reduction in IOP from baseline at every time point (P<0.001). No significant difference in mean IOP at 12 months was found, with a mean of 14.1±4.4mm Hg in the phacocanaloplasty group and 11.8±5.4mm Hg in the phacotrabeculectomy group (P=0.07). The phacotrabeculectomy group showed a significantly greater median absolute (8 vs. 5mm Hg) and percent (40% vs. 28%) reduction in IOP at 12 months (P=0.02). Postoperative glaucoma medication use was similar between the 2 groups. Overall failure rates at 1 year were comparable between the 2 groups: 22% for phacocanaloplasty versus 20% for phacotrabeculectomy (P=0.79). Phacotrabeculectomy eyes experienced more visual failures (5% vs. 0%, P=0.50), whereas phacocanaloplasty experienced more IOP failures (17% vs. 12%, P=0.75). No difference in operative failure rate was found between the phacocanaloplasty and phacotrabeculectomy groups (6% vs. 5%,P=1.00) and this held after controlling for covariates. Final VA was not statistically different between the 2 groups.
Conclusions: Phacocanaloplasty and phacotrabeculectomy both achieved significant reduction in IOP and improvement in VA at 12 months with comparable success rates. Phacotrabeculectomy achieved a statistically greater median percentage decrease in IOP, but the 2 procedures resulted in comparable mean IOP at 12 months.
Surgical options for glaucoma have expanded in recent years. This article provides an evidence-based update on the novel or emerging surgical techniques for the treatment of open-angle glaucoma that are based on the Schlemm's canal (SC). Canaloplasty is an ab externo approach and was developed as an alternative to traditional filtering surgeries. The Hydrus microstent (Ivantis Inc., Irvine, CA) is a so-called SC scaffold that directly bypasses the trabecular meshwork to drain aqueous humor into the SC, which it keeps dilated over approximately one quadrant. Canaloplasty has also been shown to lower intraocular pressure (IOP) by up to 40% and combined with cataract surgery. IOP was lowered 44% at 24 months while maintaining a favorable safety profile. The Hydrus device has been proposed as an adjunct to cataract extraction surgery. To date, no published evidence from clinical trials is available on its in vivo safety and efficacy. Schlemm's canal based glaucoma procedures show promise as alternative treatments to traditional glaucoma surgery. Surgeons must be comfortable with angle anatomy. A prerequisite for functionality of these techniques is the integrity of the distal outflow system. At present, however, it is not possible to conclude whether these novel procedures will be viable alternatives to standard filtering surgery over the long-term.
Purpose: To evaluate the efficacy and safety of the ultrasonic circular cyclocoagulation procedure in patients with open-angle glaucoma naïve of previous filtering surgery.
Methods: Prospective non-comparative interventional clinical study conducted in five French University Hospitals. Thirty eyes of 30 patients with open-angle glaucoma, intraocular pressure (IOP) > 21 mmHg and with no previous filtering glaucoma surgeries were sonicated with a probe comprising six piezoelectric transducers. The six transducers were activated with a 6-s exposure time. Complete ophthalmic examinations were performed before the procedure and at 1 day, 1 week, 1, 2, 3, 6 and 12 months after the procedure. Primary outcomes were surgical success (defined as IOP reduction from baseline ≥ 20% and IOP > 5 mmHg with possible retreatment and without hypotensive medication adjunction) at the last follow-up visit and vision-threatening complications. Secondary outcomes were mean IOP at each follow-up visit compared to baseline, medication use, complications and retreatments.
Results:IOP was significantly reduced (p < 0.05) from a mean preoperative value of 28.2 ± 7.2 mmHg (n = 3.6 hypotensive medications) to 19.6 ± 7.9 mmHg at 12 months (n = 3.1 hypotensive medications and n = 1.1 procedures) (mean IOP reduction of 30%). Success was achieved in 63% of eyes (19/30) at 12 months (mean IOP reduction of 37% in these eyes). No major intra- or postoperative complications occurred.
Conclusions: The ultrasonic circular cyclocoagulation procedure seems to be an effective and well-tolerated method to reduce IOP in patients with open-angle glaucoma without previous filtering surgery.
Canaloplasty is a highly effective, minimally invasive, surgical technique indicated for the treatment of open-angle glaucoma that works by restoring the function of the eye’s natural outflow system. The procedure’s excellent safety profile and long-term efficacy make it a viable option for the majority of glaucoma patient types. It can be used in conjunction with existing drug based glaucoma treatments, after laser or other types of incisional surgery, and does not preclude or affect the outcome of future surgery. Numerous scientific studies have shown Canaloplasty to be safe and effective in lowering IOP whilst reducing medication dependence. A recent refinement of Canaloplasty, known as ab-interno Canaloplasty (ABiC), maintains the IOP-lowering and safety benefits of traditional (ab-externo) Canaloplasty using a more efficient, simplified surgical approach. This paper presents a review of Canaloplasty indications, clinical data, and complications, as well as comparisons with traditional incisional glaucoma techniques. It also addresses the early clinical evidence for ABiC.
Purpose This study was conducted to analyse the intraocular pressure (IOP)-lowering and drug-sparing effect of microinvasive 360-degree suture trabeculotomy after successfully
Methods This retrospective interventional study included patients with open angle glaucoma or secondary forms of glaucoma, suffering from insufficient IOP level after previously conducted canaloplasty. To enhance the IOP-lowering canaloplasty effect, all patients underwent micro-invasive 360-degree suture trabeculotomy as a conjunctiva-sparing ab interno approach for circumferential trabeculotomy. This was achieved by introducing end-gripping forceps into the anterior chamber with topical anaesthesia, and grasping and extracting the canaloplasty suture through the trabecular meshwork under gonioscopic visualisation. Main outcome measures were IOP reduction and the number of IOP-lowering medications after 3 and 12 moths. Intraoperative and postoperative complications were documented systematically.
Results In total, 88 eyes of 88 patients were included. Mean IOP reduction after micro-invasive 360-degree suture trabeculotomy at month 3 was 37.5 % (from baseline 22.8±6.7 mmHg to 14.3±3.1 mmHg, p<0.01) and 41.2 % after 12 months (from 22.8±6.7 mmHg to 13.4±2.3 mmHg, p<0.01). The number of IOP-lowering medications decreased significantly from a mean of 2.7±1.4 to 1.3±1.4 after 3 months, and 1.6±1.2 after 12 months. No serious complications were observed. However, mild or moderate retrograde
bleeding from the collector channels was present in 25 % of eyes that resorbed spontaneously in all cases.
Conclusions Micro-invasive 360-degree suture trabeculotomy represents a simple and safe minimal invasive ab interno technique to postoperatively enhance the IOPlowering
and drug-sparing effect of canaloplasty
Purpose: To analyze the impact of surgically induced astigmatism on IOP results after canaloplasty. Methods Prospective nonrandomized evaluation of 57 consecutive eyes of 37 patients with open-angle glaucoma undergoing canaloplasty Best corrected visual acuity (BCVA), IOP by Goldman applanation tonometry, astigmatism value assessed with both auto kerato-refractometer and refractive corneal maps (AS-OCT SS-1000 CASIA), number of antiglaucoma medication used and secondary antiglaucoma procedure were assessed preoperatively and at 1 day, 7 days, 4 weeks, and 3, 6, 12 months postoperatively. In order to evaluate if there is any association between surgically induced astigmatism on IOP results, patients were divided into 3 groups according to surgically induced astigmatism value in the first postoperative day: group 1 (22 eyes) with astigmatism from 0 to 3 CYL Results The mean preoperative IOP was: group 1 – 18.1mm Hg , group 2 – 21.75 mmHg, group 3 – 19.5mmHg . The mean IOP decreased to 14.3 mmHg, 13.8 mmHg, 11.8 mmHg at 12 months in group 1, 2, and 3 respectively. Mean astigmatism preoperatively was 0.6 CYL in group 1; 0.8 CYL in group 2 and 0.86 CYL in group 3. It was still in the same range at 1 week postoperatively. Thereafter the astigmatism underwent a spontaneous decline, reaching 0.75 CYL in group 1, 1.39 CYL in group 2 and 2.5 CYL in group 3 at 4 weeks. Six months after canaloplasty, mean astigmatism reached the preoperative range of 0.61 CYL in group 1, 0.82 CYL in group 2 and 0.98 CYL in group 3. Conclusion Patients with the highest postoperative astigmatism had the lowest IOP at 12 months. None of the patients from the group with the highest amount of postoperative astigmatism required antiglaucoma treatment or additional antiglaucoma procedures. The amount of surgically induced astigmatism on the first postoperative day correlate inversely with IOP at 12 months. Further studies are needed to fully assess that relation.
Ab interno trabeculectomy with the Trabectome® (NeoMedix, Tustin, CA, US) is a minimally invasive glaucoma surgery that has the capacity to significantly lower intraocular pressure (IOP) with a highly favorable safety profile compared with traditional glaucoma surgeries. Since the first results were reported in 2005, mostly for primary open-angle glaucoma, the indications have since expanded to include secondary open- and closed-angle glaucoma. Exclusion criteria are active neovascular and uveitic glaucoma, and glaucoma due to increased episcleral pressure. On average, IOP is typically lowered by 30–40 % into the midteens, while decreasing the number of medications by one. Postoperative IOP can be estimated using a calculator. Patients with a higher preoperative IOP have the largest IOP reduction. Transient hyphema is a common postoperative observation. In this article, we will review surgical technique, patient management, postoperative care, and outcomes
Purpose: The purpose of the study is to investigate the role of SLT in glaucoma patients who had previously undergone a canaloplasty. Methods A retrospective systematic review of outcomes of SLT in patients with a prior canaloplasty was performed using the Dean McGee Eye Institute database. Of the 54 patients identified from 2010 to August 2014, 37 were excluded because SLT was performed on a different eye, before the canaloplasty, or a major glaucoma surgery was done prior to SLT. A total of 17 patients and 19 eyes were analyzed. Failure of therapy was defined as a less than 20% reduction in IOP with no decrease in IOP medications after 2-4 weeks, increase in IOP medications, or need for future IOP-lowering surgery. Results 11 of the 19 underwent YAG goniopuncture prior to SLT. Of the 19 eyes, 5 had SLT done prior to canaloplasty. Average time between Canaloplasty and SLT was 17 months (range 7-30). IOP was decreased to 21 or less in 10 patients (53%), 18 or below in 7 patients (37%), 15 or below in 3 paients (16%). IOP was lowered by 20% in 3 patients (16%) and was sustained over 2.5 year follow up. Of the remainder 16 eyes, 8 required further surgical intervention, 2 required increase in medications, and 6 were continued to be monitored. Conclusion Based on this study, a greater than 20% reduction of IOP 2-4 weeks after SLT in canaloplasty creates a sustainable and beneficial effect on IOP. Future studies with a larger, less refractory treatment group would be beneficial.
Purpose Some are apprehensive about utilizing canaloplasty given its use of conjunctiva and potentially higher risk of failure of subsequent filter. Our goal was to investigate the efficacy of Ex-PRESS shunt surgery after failed canaloplasty. Methods A retrospective review was performed of 20 consecutive eyes requiring filtration surgery after failed canaloplasty. All patients had open angles. The primary outcome measure was surgical success. Secondary outcomes included visual acuity, intraocular pressure (IOP), number of medications, and complications. Results Mean follow-up time post-Ex-PRESS was 741 ± 334 days. Mean time from canaloplasty to Ex-PRESS shunt surgery was 250 +/- 135 days. Pre-operative IOP and number of medications were 31.7 +/-10.3 and 2.3 +/- 1.4, respectively. Surgical success at final follow-up was 75% with or without medications. At final follow-up, mean IOP and number of medications were 12.6 ± 5.4 and 0.8 +/- 1.1 . No major complications were reported. Conclusion Ex-PRESS shunt surgery after failed canaloplasty is efficacious and safe. Surgical success is similar to both tube versus trabeculectomy and primary Ex-PRESS shunt surgery data. Glaucoma specialists need not fear that good canaloplasty candidates will have worse outcomes should a subsequent filter be needed.
PURPOSE: To evaluate critically visual field (VF) improvement in participants in the Collaborative Initial Glaucoma Treatment Study (CIGTS). DESIGN: Prospective, comparative case series from a randomized clinical trial comparing trabeculectomy and
topical medications in treating open-angle glaucoma (OAG). METHODS: A total of 607 subjects with newly diagnosed OAG were identified for study. Baseline and follow-up VF tests were obtained and mean deviation (MD) change from baseline over follow-up was analyzed. Clinically substantial change (loss or improvement) was defined as change from baseline of ‡3 decibels in MD. Baseline factors were inspected to determine their association with VF improvement in repeated measures regression
models. RESULTS: The percentage of participants showing substantial VF improvement over time was similar to that showing VF loss through 5 years after initial treatment, after which VF loss became more frequent. Measures of better intraocular pressure (IOP) control during treatment were significantly predictive of VF improvement, including a lower mean IOP, a lower minimum IOP, and lower sustained levels of IOP over follow-up. Other predictive factors included female sex (odds ratio [OR] [ 1.73), visits 1 year prior to cataract extraction (OR [ 0.11), and an interaction between treatment and baseline MD wherein surgically treated subjects with worse baseline VF loss were more likely to show VF improvement. CONCLUSIONS: In the CIGTS, substantial VF loss and improvement were comparable through 5 years of follow-up, after which VF loss became more frequent. Predictive factors for VF improvement included several indicators of better IOP control, which supports the postulate that VF improvement was real.
Purpose: To demonstrate that a surgical resident can develop the skills needed to perform successful canaloplasties to lower intraocular pressure without undue risk to patients.
Patients and Methods: This study is a retrospective, interventional analysis of the first ten consecutive canaloplasty cases performed by a resident surgeon. All patients were diagnosed with primary open angle glaucoma, and the clinical parameters made them acceptable candidates for canaloplasty. Seven of the patients were phakic while three were pseudophakic. Canaloplasty alone was performed in the first five consecutive cases, whereas phacocanaloplasty was completed successfully in the remaining five patients. The surgical procedure was video recorded for post-operative analysis by the resident and attending surgeon. The canaloplasty procedure was subdivided into ten essential surgical steps, which were then timed and reviewed. The glaucoma specialist allowed the resident increasing levels of surgical independence as he gained proficiency in the procedure. Intraoperative complications were recorded. Post-operative intraocular pressures as well as the number of pressure controlling medications the patient used were compared to the pre-operative data.
Results: Post-operative IOP measures and mean number of glaucoma medications were found to be significantly lower than those obtained preoperatively. Post-operative IOP was reduced to 17.4 ± 6.1 mmHg from 24.2 ± 5.4 mmHg (p = 0.0061), and mean glaucoma medication usage reduced to 0.4 ± 0.9 from 2.7 ± 1.3 (p = 0.0078). On average, the total resident operative time was twice that of the representative glaucoma specialist (30 min 40 seconds ± 5 min 57 seconds vs. 16 min 30 seconds; p < 0.0001). Challenging steps were determined to be the following: performing the conjunctival peritomy, placement of the 10-0 polypropylene suture, cutting the deep scleral flap, placement of an appropriate slip knot, and conjunctival closure. The glaucoma specialist determined the resident was proficient in these steps after the sixth surgical case. More importantly, target post-operative intraocular pressures were adequately obtained in 9 out of 10 patients.
Conclusions: Under the supervision of an experienced surgeon, a resident physician developed the skills to perform the canaloplasty procedure effectively. Patients achieved adequate post-operative intraocular pressure lowering while reducing their burden of glaucoma medications.
When medical therapy fails to control intraocular pressure, the standard surgical approaches for treating glaucoma are trabeculectomy and aqueous shunt implantation. However, alternative surgical techniques and devices are being investigated in an effort to avoid the potentially serious complications associated with filtering procedures. In patients who have previously undergone incisional glaucoma surgery, surgical options may be particularly limited because of conjunctival scarring. One novel device that has gained significant interest is the Gold Shunt, a non-valved flat-plate drainage implant that diverts aqueous humor from the anterior chamber into the suprachoroidal space. Ideally, this ‘blebless’ procedure is less prone to the postoperative complications that can lead to failure in standard glaucoma surgeries and does not rely on conjunctival manipulation or integrity to form a bleb. This device profile reviews the current literature and evidence for Gold Shunt implantation in refractory glaucoma.
Micro-invasive glaucoma surgery with the Glaukos iStent® or iStent inject® (Glaukos Corporation, Laguna Hills, CA, USA) is intended to create a bypass through the trabecular meshwork to Schlemm’s canal to improve aqueous outflow through the natural physiologic pathway. While the iStent devices have been evaluated in ex vivo anterior segment models, they have not previously been evaluated in whole eye perfusion models nor characterized by computational fluid dynamics. Intraocular pressure (IOP) reduction with the iStent was evaluated in an ex vivo whole human eye perfusion model. Numerical modeling, including computational fluid dynamics, was used to evaluate the flow through the stents over physiologically relevant boundary conditions. In the ex vivo model, a single iStent reduced IOP by 6.0 mmHg from baseline, and addition of a second iStent further lowered IOP by 2.9 mmHg, for a total IOP reduction of 8.9 mmHg. Computational modeling showed that simulated flow through the iStent or iStent inject is smooth and laminar at physiological flow rates. Each stent was computed to have a negligible flow resistance consistent with an expected significant decrease in IOP. The present perfusion results agree with prior clinical and laboratory studies to show that both iStent and iStent inject therapies are potentially titratable, providing clinicians with the opportunity to achieve lower target IOPs by implanting additional stents.
In our previous studies of bovine eyes, herniations of the inner wall and JCT into collector channel ostia were observed after acute increases in IOP. But these herniations were partially eyes were a common feature even at 0 mmHg, suggesting that a normally reversible process of or completely reversed after reducing the IOP to normal levels. In contrast, the herniations in POAG hernia formation and dissolution becomes irreversible in POAG. It is important to recall that resistances in series are additive. As such, this previously unrecognized structural alteration may be an important factor contributing to the pathogenesis of POAG and elevated outflow resistance in POAG, even beyond whatever additional resistance is present in the trabecular meshwork
Aqueous humor outflow occurs through the conventional and unconventional pathway. With aging, the latter becomes less active so that the conventional pathway remains the primary mechanism of aqueous humor outflow. An abnormality of this pathway contributes significantly to disordered aqueous humor dynamics and consequent rise in intraocular pressure seen in primary open angle glaucoma and ocular hypertension. Recently, the ocular lymphatics have been implicated in aqueous humor outflow. Additionally, the trabecular meshwork is now understood to be a complex organization of structures, which are controlled by various biomechanical and biochemical mechanisms. Among others, these include the actinomyosin cytoskeletal system, extracellular matrix, intracellular signaling responses mediated by protein kinase C, Rho/Rho kinase, and other biologic factors. This review shall describe the various pathophysiologic mechanisms involved in aqueous humor dynamics
Pre-Descemet hematoma is a rare and early complication of a canaloplasty procedure that usually occurs during the first 24 hours after surgery and is preceded by a nonhemorrhagic Descemet membrane detachment that may occur during viscodilation of Schlemm canal. An early surgical approach avoids serious complications,and various techniques, both surgical and laser, have been described. Pre-Descemet hemorrhage can occur not only after the canaloplasty procedure but also as an intrasurgical complication. It can be successfully repaired within the same procedure with good anatomical and functional outcomes. Surgical removal of the hematoma through the corneal tunnel seems to be the best approach in eyes with a clear crystalline lens.
Surgery with the iStent (Glaukos Corporation, Laguna Hills, CA, USA), a trabecular bypass stent, has been added as an option for the treatment of mild to moderate glaucoma. It is a 1 mm titanium stent used to directly shunt aqueous from the anterior chamber into Schlemm’s canal. The published literature indicates that it can be used in open-angle glaucomas to achieve an IOP in the mid-teens. No vision threatening complications related to the device have been reported
PURPOSE. Our previous work indicated that a larger circumferential Young’s modulus (E) of trabecular meshwork (TM) correlated with a higher outflow facility (C) in normal human donor eyes. The current study investigated the influence of glaucomatous TM stiffness and cellularity on C. METHODS. Eight left eyes from glaucomatous human donors were perfused within 48 hours post mortem. Values of C were determined at pressures of 10, 20, 30, and 40 mm Hg. The TM was then dissected and imaged with optical coherence tomography to determine its crosssectional area. Uniaxial tensile stress was applied longitudinally to TM segments to determine stress-strain curves. E was calculated at zero strain, representing the circumferential stiffness of the TM at a relaxed state. Confocal images of DAPI-stained TM segments were used to determine cellularity after mechanical stretching.
RESULTS. C (lL/min/mm Hg) of glaucomatous eyes was 0.18 6 0.02 (mean 6 SE) at 10 mm Hg and decreased to 0.11 6 0.02 when the pressure was increased to 40 mm Hg. C measured at 30 and 40 mm Hg correlated with TM cellularity. E was 12.5 MPa and 1.4
(geometric mean and SE) and did not statistically correlate with postmortem time, age, C, or cellularity. CONCLUSIONS. Compared with data of normal eyes observed in a previous study, C in glaucomatous eyes was reduced significantly, and the amount of reduction increased with increasing the pressure. E of glaucomatous TM was approximately one-fifth that of normal TM. Prospective studies are needed to further investigate the influence of TM tensile stiffness on outflow regulation.
Conclusions: Trabeculectomy is associated with a stronger sustained IOP reduction and less need for postoperative medication as compared to canaloplasty, at the cost of a higher rate of early complications. If target pressure is attainable by moderate IOP reduction, canaloplasty may be considered for its relative ease of postoperative care and lack of bleb-related complications.
Purpose: To evaluate safety and clinical outcomes of a novel supraciliary device, the CyPass Micro-Stent, for surgical treatment of open-angle glaucoma when implanted in conjunction with cataract surgery.Patients and Methods: Subjects (n=142) with open-angle glaucomaand cataract underwent combined phacoemulsification, with intraocular lens insertion, and microstent implantation into the supraciliary space of study eyes (n=167). Two analysis cohorts were prespecified based upon medicated baseline intraocular pressure (IOP): Z21mm Hg (cohort 1, n=65) or <21mm Hg (cohort 2, n=102). Glaucoma medications were discontinued or tapered at surgery, and restarted at investigator discretion. The main postoperative outcome measures were adverse events, IOP changes,
and number of IOP-lowering medications.
Results: Mean±SD follow-up was 294±121 days. No major intraoperative or postoperative complications occurred. Preoperative baseline mean IOP was 20.2±6.0mm Hg and mean number of IOP-lowering medications was 2.0±1.1. Cohort 1 showed a 35% decrease in mean IOP and a 49% reduction in mean glaucoma medication usage; cohort 2 demonstrated a 75% reduction in mean medication usage while maintaining mean IOP<21 mm Hg. For all eyes, mean IOP at 12 months was 15.9±3.1mm Hg (14% reduction from baseline). Early and late postoperative IOP elevation occurred in 1.2% and 1.8% of eyes, respectively. Two subjects developed mild transient hyphema, and none exhibited prolonged inflammation, persistent hypotony, or hypotony maculopathy. Conclusions: CyPass Micro-Stent implantation, combined with cataract surgery, resulted in minimal complications and reduced IOP and IOP-lowering medication use at 12 months postoperatively.
Purpose of review: To review the current literature regarding the effectiveness and risks of new surgeries that can be combined with phacoemulsification in the management of cataract and glaucoma. Recent findings: Surgical options for concurrently managing cataract and glaucoma have expanded in recent years. Endoscopic cyclophotocoagulation, trabecular micro-bypass stent, ab interno trabeculectomy, and canaloplasty may be performed in conjunction with cataract extraction to provide additional intraocula rpressure (IOP) reduction. Studies evaluating these new glaucoma procedures combined with phacoemulsification generally include retrospective case series without a comparison group. Because cataract surgery alone is associated with IOP reduction, the relative contribution of the glaucoma procedure in lowering IOP cannot be determined in these studies. Randomized clinical trials are needed to better evaluate the efficacy and safety of newer glaucoma procedures in combination with cataract surgery. Summary: The newer glaucoma procedures appear less effective than trabeculectomy, but they are associated with a lower risk of surgical complications.
Background: Trabeculectomy (TET) is still the gold standard in incisional glaucoma surgery. It achieves an efficient intraocular pressure (IOP) reduction. Unfortunately postsurgical complications of the procedure are frequent. Canaloplasty is a non-penetrating procedure, which aims at restoration of the natural aqueous outflow pathways, without subconjunctival drainage. Aim: This study has compared both surgical procedures concerning IOP, defined success criteria, postoperative medication, visual acuity and postoperative complications/interventions. Patients and Methods: In a retrospective study 22 eyes after trabeculectomy and 22 eyes after canaloplasty were included. IOP, complete and qualified success, postoperative medication, visual acuity and complications/interventions were recorded at 6 month, 12 month and at last follow-up postoperatively. Results: The mean IOP in the trabeculectomy and canaloplasty groups decreased from 23.91 ± 10.68 mmHg to 10.82 ± 3.67 mmHg and from 23.68 ± 7.57 mmHg to 14.50 ± 3.80 mmHg, respectively. The postoperative complications and interventions between the two groups did not reveal a statistically significant difference. Complete success (IOP < 21 mmHg and 20 % IOP reduction from baseline without medication) was achieved in 18 eyes (81.8 %) after trabeculectomy and in 11 eyes (50.0 %) after canaloplasty (p = 0.026). Conclusion: Canaloplasty and trabeculectomy are safe and effective procedures in the treatment of open-angle glaucoma. Both surgical methods reduce the IOP and the postoperative medication to a statistically significant extent. Trabeculectomy attains higher long-term complete success rates accompanied by slightly increased early postoperative complication rates (n. s.), compared to canaloplasty
".....I share Dr Fellman's great enthusiasm for where the glaucoma surgical field is headed, but it is not likely that all novel glaucoma surgical procedures will turn out to be equally effective and those associated with greater efficacy, all other things being equal, may be more widely adopted. Although the word “miracle” does not come to mind, I concur with Dr Fellman's suggestion that the availability of a novel glaucoma procedure that allows a meaningful incremental benefit in terms of IOP lowering and
reduced necessity for medications beyond the effect of cataract surgery alone, represents an important advance in patient care; one that will have substantial public health benefit throughout the world. But this will only be the case if the procedure, no matter how elegant, meets some minimal efficacy standard that is considered acceptable to both the practitioner and the patient. It is generally good medical practice to provide a patient with information regarding the likelihood of both the risks and benefits of any operative procedure before, rather than after, the surgery is performed. Simply stating that a glaucoma procedure added on to phacoemulsification is likely to lower IOP and decrease dependence on glaucoma medications without providing estimates of the magnitude of such benefits owing to the glaucoma surgery may lead to patient disappointment postoperatively. In addition to being requisite for regulatory approval, good scientific evidence regarding the safety and efficacy of novel glaucoma procedures added to cataract surgery should be accumulated to share with patients faced with making decisions regarding whether to opt for cataract surgery alone, combined with traditional glaucoma filtration surgery, or with one of the novel adjunctive procedures........"
Prior failed canaloplasty did not affect the mid-term surgical outcomes of subsequent trabeculectomy in our small cohort of patients.
Purpose: To describe the population at risk of having a severe bleb leak needing a surgical repair in the operating room and to study risk factors associated with severe bleb leak. Patients and Methods: In this case-control study, 17 cases were enrolled and paired with 51 controls. We studied all patients having a surgical revision in our center for a severe bleb leak between January 1 and December 31, 2008. Three controls were paired to
each case based on their surgery date. We then analyzed risk factors related to the patient, the intervention, and the postoperative follow-up. Results: Younger age was the only statistically significant risk factor for a severe bleb leak in our study. The odds of a severe bleb leak decreased as the age increased (P=0.0029). In comparing the risk for a severe bleb leak in younger (below 55 y) versus patients aged 75 years or older, the odds ratio was 21.0. There were no statistically significant differences between cases and controls with respect to: type of glaucoma, number or types of previous ocular
surgeries, number of preoperative topical medications, localization of the leak, localization of the wound (fornix or limbus-based), or the intraocular pressure on day 1 postoperative. Conclusions: Younger age at the time of trabeculectomy may be a risk factor for severe bleb leak. A trend was observed in which the patients under the age of 55 years were at greater risk for a severe bleb leak.
Background: Glaucoma is the second commonest cause of blindness worldwide. Non-penetrating glaucoma surgeries have been developed as a safer and more acceptable surgical intervention to patients compared to conventional procedures. Objectives: To compare the effectiveness of non-penetrating trabecular surgery compared with conventional trabeculectomy in people with glaucoma. Search methods: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 8), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to September 2013), EMBASE (January 1980 to September 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to September 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and theWHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en).We did not use any date or language restrictions in the electronic searches for trials.We last searched the electronic databases on 27 September 2013. Selection criteria: This review included relevant randomised controlled trials (RCTs) and quasi-RCTs on participants undergoing standard trabeculectomyfor open-angle glaucoma compared to non-penetrating surgery, specifically viscocanalostomy or deep sclerectomy, with or without adjunctive measures. Data collection and analysis: Two review authors independently reviewed the titles and abstracts of the search results. We obtained full copies of all potentially eligible studies and assessed each one according to the definitions in the ’Criteria for considering studies’ section of this review.We used standard methodological procedures expected by The Cochrane Collaboration. Main results: We included five studies with a total of 311 eyes (247 participants) of which 133 eyes (participants) were quasi-randomised. One hundred and sixty eyes which had trabeculectomy were compared to 151 eyes that had non-penetrating glaucoma surgery (of which 101 eyes had deep sclerectomy and 50 eyes had viscocanalostomy). The confidence interval (CI) for the odds ratio (OR) of success (defined as achieving target eye pressure without eye drops) does not exclude a beneficial effect of either deep sclerectomy or trabeculectomy (OR 0.98, 95% CI 0.51 to 1.88). The odds of success in viscocanalostomy participants was lower than in trabeculectomy participants (OR 0.33, 95% CI 0.13 to 0.81). We did not combine the different types of non-penetrating surgery because there was evidence of a subgroup difference when examining total success. The odds ratio for achieving target eye pressure with or without eye drops was imprecise and was compatible with a beneficial effect of either trabeculectomy or non-penetrating filtration surgery (NPFS) (OR 0.79, 95% CI 0.35 to 1.79). Operative adjuvants were used in both treatment groups; more commonly in the NPFS group comparedto the trabeculectomy group but no clear effect of their use could be determined. Although the studies were too small to provide definitive evidence regarding the relative safety of the surgical procedures we noted that there were relatively fewer complications with non-filtering surgery compared to trabeculectomy (17% and 65% respectively). Cataract was more commonly reported in the trabeculectomy studies. None of the five trials used quality of life measure questionnaires. The methodological quality of the studies was not good. Most studies were at high risk of bias in at least one domain and for many, there was lack of certainty due to incomplete reporting. Adequate sequence generation was noted only in one study. Similarly, only two studies avoided detection bias. We detected incomplete outcome data in three of the included studies. Authors’ conclusions: This review provides some limited evidence that control of IOP is better with trabeculectomy than viscocanalostomy. For deep sclerectomy, we cannot draw any useful conclusions. This may reflect surgical difficulties in performing non-penetrating procedures and the need for surgical experience. This review has highlighted the lack of use of quality of life outcomes and the need for higher methodological quality RCTs to address these issues. Since it is unlikely that better IOP control will be offered by NPFS, but that these techniques offer potential gains for patients in terms of quality of life, we feel that such a trial is likely to be of a non-inferiority design with quality of life measures.
Purpose: To introduce a minimally invasive, ab interno approach to a circumferential 360-degree trabeculotomy and to report the preliminary results. Design: Retrospective, noncomparative cases series. Participants: Eighty-five eyes of 85 consecutive patients who sought treatment at Glaucoma Associates of Texas with uncontrolled open-angle glaucoma and underwent gonioscopy-assisted transluminal trabeculotomy (GATT) for whom there was at least 6 months of follow-up data. Methods: Retrospective chart review of patients who underwent GATT by 4 of the authors (D.S.G., D.G.G., O.S., R.L.F.) between October 2011 and October 2012. The surgery was performed in adults with various openangle glaucomas.
Main Outcome Measures: Intraocular pressure (IOP), glaucoma medications, visual acuity, and intraoperative as well as postoperative complications.
Results: Eighty-five patients with an age range of 24 to 88 years underwent GATT with at least 6 months of follow-up. In 57 patients with primary open-angle glaucoma, the IOP decreased by 7.7 mmHg (standard deviation [SD], 6.2 mm Hg; 30.0% [SD, 22.7%]) with an average decrease in glaucoma medications of 0.9 (SD, 1.3) at 6 months. In this group, the IOP decreased by 11.1 mmHg (SD, 6.1 mmHg; 39.8% [SD, 16.0%]) with 1.1 fewer glaucoma medications at 12 months. In the secondary glaucoma group of 28 patients, IOP decreased by 17.2 mmHg (SD, 10.8 mmHg; 52.7% [SD, 15.8%]) with an average of 2.2 fewer glaucoma medications at 6 months. In this group, the IOP decreased by 19.9 mmHg (SD, 10.2 mmHg; 56.8% [SD, 17.4%]) with an average of 1.9 fewer medications (SD, 2.1) at 12 months. Treatment was considered to have failed in 9% (8/85) of patients because of the need for further glaucoma surgery. The cumulative proportion of failure at 1 year ranged from 0.1 to 0.32, depending on the group. Lens status or concurrent cataract surgery did not have a statistically significant effect on IOP in eyes that underwent GATT at either 6 or 12 months (P>0.35). The most common complication was transient hyphema, seen in 30% of patients at the 1-week visit. Conclusions: The preliminary results and safety profile for GATT, a minimally invasive circumferential trabeculotomy, are promising and at least equivalent to previously published results for ab externo trabeculotomy.
Background: In this study, a conjunctival-sparing ab interno approach for circumferential trabeculotomy, termed micro-invasive suture trabeculotomy (MIST) and its preliminary results are presented.
Design: Retrospective case-series in a university setting.
Participants: Thirty one patients with open-angle glaucoma with history of canaloplasty.
Methods: A conjunctival-sparing ab interno approach for circumferential trabeculotomy, termed micro-invasive suture trabeculotomy (MIST).
Main Outcome Measures: Mean decrease of intraocular pressure (IOP) and number of pressure-lowering medications. Results: Mean decrease of IOP was 11.1 mmHg (standard deviation [SD], 9.9 mmHg) at six months, 12.1 mmHg (SD, 10.5 mmHg) at 12 months and 13.5 mmHg (SD, 11.4 mmHg) at 24 months. The average percent lowering of IOP was 36.7% (SD, 32.8%) at six months, 41.4% (SD, 35.9%) at 12 months and 44.6% (SD, 37.7%) at 24 months. The number of pressure-lowering medications decreased by 1.1 (SD, 1.3) at month six, by 1.2 (SD, 1.5) at month 12, and by 1.3 (SD, 1.6) at month 24.
Conclusions: MIST is a promising approach for the treatment of open-angle glaucoma which is insufficiently controlled with canaloplasty. The procedure achieved significant and sustained lowering of the intraocular pressure and demonstrated an excellent safety profile. The main advantages of the procedure are: easy to learn, fast to perform, and sparing of the conjunctiva for further filtration surgery, if necessary.
A microcatheter filled with 1.25 μg of indocyanine green (ICG) diluted in 1mL of viscoelastic solution was placed into the Schlemm canal (SC) to enlarge the drainage canal; the dye was then injected into the SC. Near-infrared fluorescence real images of aqueous humor outflow structures in in vivo human eyes were obtained. A, Introduction of the flexible
microcatheter into the lumen of the SC. B, Infrared picture at the beginning of ICG injection. C, After injection of ICG plus viscoelastic, visualization of the SC, collector channels, and 3 aqueous veins (arrowheads). The fourth aqueous vein is masked by the microcatheter. D, Higher-magnification image showing in detail the aqueous vein morphology. The method
is simple and safe and makes possible the real visualization of the aqueous humor outflow system during canaloplasty
Minimally invasive glaucoma surgeries (MIGS) can improve the conventional, pressure-dependent outflow by bypassing or ablating the trabecular meshwork (TM), or creating alternative drainage routes into the suprachoroidal or subconjunctival space. They have a highly favourable risk profile compared to penetrating surgeries, and lower intraocular pressure with variable efficacy that may depend on the extent of outflow segments accessed. Since they are highly standardised procedures that use clear corneal incisions, they can elegantly be combined with cataract and refractive procedures to improve vision in the same session. There is a growing need for surgeons to become proficient in MIGS to address the increasing prevalence of glaucoma and cataracts in a well-informed, aging population. Techniques of visualisation and instrumentation in an anatomically highly confined space with semitransparent tissues are fundamentally different from other anterior segment surgeries, and present even experienced surgeons with a substantial learning curve. Here, we provide practical tips, and review techniques and outcomes of TM bypass and ablation MIGS.
Purpose: To determine improvement in outflow facility (C) in human anterior segments implanted with a novel Schlemm’s canal scaffold (Hydrus™ Microstent, Ivantis, Inc.) or two trabecular micro-bypasses (iStent®, Glaukos, Inc.). Methods: Human anterior segments were isolated from 12 pairs of eyes from donors with no history of ocular disease and then perfused at 50, 40, 30, 20 and 10 mmHg pressures for ten minutes each. Baseline C was calculated from perfusion pressures and flow rates. The scaffold was implanted into Schlemm’s canal of one anterior segment, and two micro-bypasses were implanted three clock-hours apart in the contralateral anterior segment. Outflow facility and resistance were compared at various standardized perfusion pressures and between each device. Results: Compared to baseline, C increased by 0.16±0.12 μl/min/mmHg (74%) with the scaffold, and 0.08±0.12 μl/min/mmHg (34%) with two micro-bypasses. The scaffold increased C at perfusion pressures of 50, 40, 30, and 20 mmHg (p < 0.005). Two micro-bypasses increased C at a perfusion pressure of 40 mmHg (p < 0.05). Conclusion: Both implants effectively increased outflow facility in human eyes ex vivo. The scaffold increased C by a greater percentage (73% versus 34%) and at a greater range of perfusion pressures (20 to 50 mmHg versus 40 mmHg) than the two micro-bypasses suggesting that the 8 mm dilation of Schlemm’s canal by the scaffold may have additional benefits in lowering the outflow resistance. The Hydrus Microstent scaffold may be an effective therapy for increasing outflow facility and thus reducing the intraocular pressure in patients with glaucoma.
Rebuttal: 1) blebs in CP are due to error or complication but even so very sporadic, 2) decision took into account all parameters, 3) Our resutls showed 49.4 % reduction after 2 years with mean post op IOP of 16.3 mmHg, with less risk for complications and easier management of follow-up. In closing, the aim of our short report was to show that canaloplasty can also be considered as a possible option in select patients with failed trabeculectomy, and that failed previous surgery is not always an absolute contraindication for canaloplasty, as commonly believed.
Canaloplasty is a relatively new surgical option in the treatment of open-angle glaucoma. This non-perforating technique uses a microcatheter connected to a flickering red light laser source, which is inserted within Schlemm’s canal. A 10-0 prolene suture is tied to the distal tip of the microcatheter, which is gently guided out of the canal in the opposite direction and then left tensioned while a small amount of viscoelastic agent is injected in Schlemm’s canal. The aim of this surgery is to facilitate aqueous outflow through natural pathways, with less risks of post-operative complications.
Purpose: To compare the direct cost of treating glaucoma patients with Trabectome, iStent, and endoscopic cyclophotocoagulation (ECP) versus topical medications in Ontario, Canada. Costs are projected over a 6-year period, and presented on a per-patient level from the perspective of the Ontario Health Insurance Plan (OHIP). Methods: The per-bottle cost of each medication was obtained from the 2011 Ontario Drug Benefit (ODB) formulary. A wastage adjustment fee was added to the cost, as was a pharmacy markup,and an ODB dispensing fee. Previously published medication prescription rates were used to determine the frequency with which each medication is prescribed. We estimated the overall cost by taking a weighted average of the cost of each class of glaucoma medications. The cost of each glaucoma device was determined by contacting local distributors.We then added the cost of disposables used during surgery (viscoelastic and keratome) to the cost of each procedure. Start-up costs for each device and surgeons’ fees were excluded from the overall cost. Results: At 6 years, treatment with the Trabectome offered a cumulative cost savings of $279.23, $1572.55, and $2424.71 per patient versus monodrug, bidrug, and tridrug therapy, respectively. A cumulative cost difference of $20.77, $1272.55, and $2124.71 per patient were found when comparing iStent versus monodrug, bidrug, and tridrug therapy, respectively. Treatment with ECP yielded a cost savings of $779.23, $2072.55, and $2924.71 per patient versus monodrug, bidrug, and tridrug therapy, respectively. Conclusions: Over a projected period of 6 years, the Trabectome, iStent, and ECP may all offer a modest cost savings to OHIP versus the cost of glaucoma medication. Further analysis of direct and indirect costs to patients as well as quality of life assessments will help further delineate the role of these treatments in the glaucoma treatment paradigm.
Purpose: To evaluate quality of life (QoL) with a new questionnaire after canaloplasty (CP) and trabeculectomy (TE).
Patients and methods: We assessed outcomes of surgery, rate of revision surgeries, patients’ mood, and influence of postoperative care on QoL, surgery interference with daily activities, and postsurgical complaints. Patients completed the QoL questionnaire 24 months after surgery.
Results: Patients who underwent CP (n=175) were compared to TE patients (n=152). In the CP group, 57% of patients expressed high satisfaction, while 41% of patients in the TE group said they were highly satisfied. The satisfaction difference was statistically significant (P=0.034). Significantly fewer second surgeries were needed after CP (8% CP versus 35% TE, P0.001). Patients were more positive in the CP group (54% CP versus 37% TE, P0.009). Stress related to postoperative care was lower in the CP group compared to the TE group (14% versus 46%). Difficulties with activities of daily living, such as reading, were much lower or even nonexistent after CP, and complaints like eye burning or stinging were significantly lower in the CP group Conclusions: Compared with TE, CP is associated with less QoL impairment and higher patient satisfaction after surgery. However, long-term data on intraocular pressure reduction after surgery are needed to confirm long-term patient satisfaction with this surgery.
Purpose: Canaloplasty is a safe and effective alternative in glaucoma surgery, avoiding the risk for hypotony and bleb-related complications. Two cases of hemorrhagic Descemet membrane detachment (DMD) after canaloplasty are reported in patients who did not have previous surgery. Results: Two patients with primary open-angle glaucoma underwent canaloplasty because of medically uncontrolled intraocular pressure (IOP). Canaloplasty was performed using a flexible microcatheter, viscoelastic material and a tensioning suture. The day after surgery, hemorrhagic DMD was observed in the inferior quadrants in both patients on slit-lamp biomicroscopy. Therapy: For the size and location (occlusion of the visual axis), aspiration of blood and descemetopexy with air tamponade were performed promptly. In both cases, a small translucent scar remained. Conclusions: Circumferential cannulation and viscodilation of the Schlemm canal increases the risk for DMD, which may be aggravated by blood reflux resulting from the tensioning suture and low postoperative IOP. Surgeons should be aware of this specific and potentially sight-threatening complication in classic canaloplasty. Immediate intervention is recommended for good visual prognosis.
Summary: Elimination of medications occurred in 7/21 (33%) eyes, Medications were reduced in 12/21 (57.1%) eyes, Number of meds remained the same in 2/21 (9.5%) eyes but IOP was lower, Canaloplastyappears to present a viable option for glaucoma control, despite previous failed glaucoma surgeries, Canaloplastyhas a role in advanced disease and across the spectrum of adult glaucomas
The elevated intraocular pressure (IOP) of primary open-angle glaucoma is caused by impaired outflow of aqueous humor through the trabecular meshwork. Within the juxtacanalicular region, alterations of both extracellular matrix homeostasis and the cellular tone of trabecular meshwork endothelial and the inner wall of Schlemm canal cells affect outflow. Newer pharmacologic agents that target trabecular meshwork and Schlemm canal cell cytoskeleton lower IOP. Aqueous drainage occurs nonhomogenously with greater flow going through certain portions of the TM and less going through other portionsda concept known as segmental flow, which is theoretically the result of outflow being dependent on the presence of discrete pores within Schlemmcanal. The limited long-term success of trabecular meshwork bypass surgeries implicates the potential impact of resistance in Schlemm canal itself and collector channels. Additionally, others have observed that outflow occurs preferentially near collector channels. These distal structures may be more important to aqueous outflow than previously believed.
Introduction: Micro-invasive glaucoma surgical implantation of trabecular microbypass stents, previously shown to be safe and effective for open-angle glaucoma (OAG) subjects during cataract surgery, was considered for evaluation as a sole procedure.
The aim of this study was to evaluate the safety and intraocular pressure (IOP)-lowering efficacy after ab interno implantation of two Glaukos Trabecular Micro-Bypass iStent inject second generation devices in subjects with OAG. This study was performed at sites in France, Germany, Italy, Republic of Armenia, and Spain.
Methods: In this pan-European, multi-center prospective, post-market, unmasked study, 99 patients with OAG on at least two topical ocular hypotensive medications who required additional IOP lowering to control glaucoma disease underwent implantation of two GTS400 stents in a stand-alone procedure. Patients were qualified if they presented with preoperative mean IOP between 22 and 38 mmHg after medication washout. Postoperatively, subjects were assessed at Day 1, Months 1, 3, 6, 7, 9, and 12. IOP, medication use and safety were assessed at each visit.
Results: Sixty-six percent of subjects achieved IOP B18 mmHg at 12 months without medication, and 81% of subjects achieved Month 12 IOP B 18 mmHg with either a single medication or no medication. Mean baseline washout IOP values decreased by 10.2 mmHg or 39.7% from 26.3 (SD 3.5)mmHg to 15.7 (SD 3.7) mmHg at Month 12. Mean IOP at 12 months was 14.7 (SD 3.1) mmHg in subjects not using ocular hypotensive medications. Reduction from preoperative medication burden was achieved in 86.9% of patients, including 15.2% with reduction of one medication and 71.7% with reduction of two or more medications. Postoperative complications occurred at a low rate and resolved without persistent effects.
Conclusion: In this series, implantation of two trabecular micro-bypass second generation
stents in subjects with OAG resulted in IOP and medication reduction and favorable safety
Purpose: Schlemm’s canal (SC) inner wall is adjacent to the juxtacanalicular trabecular meshwork (TM) over their entire circumference. We seek to transfer reporter and therapeutic genes to these outflow-modulating tissues via canaloplasty surgery in live monkeys. Methods: A standard canaloplasty surgical approach was performed in cynomolgus monkeys using flexible canaloplasty catheters, modified for monkey eyes with a 175-mm outer diameter and an LED-lighted tip. A 6-0 prolene suture was used for the exact localization of SC. Trypan blue was injected during catheter withdrawal to
document catheter placement within SC and to determine ease of injecting fluid into SC. Before, during, and after the injection, the position of the catheter and the anatomic details were video-captured with an externally positioned noncontact endoscopic imaging system and 50 mHz ultrasound biomicroscopy (UBM). Results: A 360 catheterization and injection of dye into SC was achieved. Suture, catheter, and trypan blue were imaged with the endoscope camera system and the catheter was also visualized with UBM. Trypan blue was seen in the SC over 5 clock hours after a 1 clock-hour insertion of the catheter. Conclusions: A modified canaloplasty catheter device might be used for gene delivery to the SC/TM area without circumferential catheterization. Further studies comparing different delivery methods of the vector/ transgene into the SC using canaloplasty are needed.
In conclusion, canaloplasty is a promising surgical technique for delivering gene constructs designed to decrease outflow resistance in the TM/SC region. It might also be possible to perform combined surgical suture and genetic canaloplasty. Future experiments will compare vector/transgene expression in the TM/SC region after the one clock hour and circumferential insertions, determine the effects of cannulation and vector/transgene expression on SC structures and IOP, and monitor the extent and location of GFP transgene expression in that area and its relationship to IOP. The effect of paracentesis on the pressure gradient between SC and AC and its impact on vector/transgene expression in the TM/SC region should also be investigated. All these experiments will facilitate the applicability of localized gene therapy in SC and its clinical relevance.
Purpose: To study the changes in astigmatism after canaloplasty and to analyze its correlation with long-term intraocular pressure (IOP) results. Methods: Twenty-six eyes of 26 consecutive patients with primary open-angle glaucoma (n=14) and pseudoexfoliative glaucoma (n=12) undergoing canaloplasty were included in this retrospective study. Canaloplasty comprised of 360-degree catheterisation of Schlemm canal by means of a flexible microcatheter with distension of the canal by 2 tensioning 10-0 polypropylene sutures Primary outcome measures included IOP, glaucoma medication usage, astigmatism, and adverse events at 2, 4, 12, and 24 weeks postoperatively. Results: The mean preoperative IOP was 21.1±5.8mm Hg. The mean IOP decreased to 14.25 ±4.3mm Hg at 6 months. Mean astigmatism preoperatively was 0.77±0.5 D, which increased to 3.3±1.7D at 2 weeks postoperatively (Pr0.05; Wilcoxon-test). Thereafter, the astigmatism underwent a spontaneous decline, reaching 1.9±0.8D at 4 weeks and 1.2±0.74D at 12 weeks postoperatively. Best-corrected visual acuity did not change significantly. Six months after canaloplasty, mean astigmatism reached the preoperative range of 0.86±0.52 D. Astigmatism at 2 weeks correlated significantly and inversely with IOP at 6 months (r=0.59, P=0.005; Spearman). Conclusions: The change of astigmatism after canaloplasty follows a clear time course with a maximum at 2 weeks reaching preoperative values at 6 months. The amount of surgically induced astigmatism might be helpful to predict outcome of canaloplasty in terms of IOP reduction.
In conclusion, our study shows that TE is more effective than CP in diminishing posture-induced IOP changes. These results may be clinically relevant for patients requiring a greater IOP reduction or at a higher risk for glaucoma progression
Comments include1) literature shows bleb formation in some patients after CP, 2) decision to operate depends on state ON not of SC, 3) literature shows success repeat trab similar to repeat CP but pressure lowering insufficient
Preliminary analyses of intraoperative fluorscein canalograms videos indicate that flow characteristics through the episcleral and intrascleral viens may be key markers of angle surgery outcomes. As suggested by Grieshaber et al (2010), evaluation of aqueous hhumor dynamics may help assess canaloplasty outcome. We report the new observation of obstruction (i.e. minimal to no fluorescein reflux into the anterior chamber) at the TM in JG. This observation supports the clinical indications to "remove" the outflow obstruction (e.g. trabeculotomy). This surgeon's early experience showed the following: 1) post-operative mean IOPs clustered around 11.8 mmHg, which is comparable to the 3-year interim results (Lewis et al. 2011) and 2) canaloplasty is possible after failed trabeculectomy as previously reported (Brusini and Tosoni 2014). Additional analysis is underway to quantify fluorescein reflux into the anterior chamber, blood reflux into the anterior chamber and fluorescein diffusion pattern into the aqueous veins and deep scleral plexus to further elucidate mechanisms of outflow resistance.
Objective: To evaluate the safety and efficacy of circumferential viscodilation and tensioning of Schlemm’s canal (canaloplasty) in the treatment of uveitic glaucoma(UG).
Design: Pilot, retrospective,non comparative case series.
Participants: Nineteen uveitic eyes of 15 patients with UG. Methods: The main outcome measure was surgical success.Secondary outcome measures included intraocular pressure, usage of
ocular hypotensive medication,visual acuity,and sight-threatening complications. Patients were included when UG could not be
controlled despite maximum tolerated medical therapy. Exclusion criteria were peripheral anterior synechiae and previous
glaucoma surgery. Results: Mean follow-up time from canaloplasty was 2.6 +/- 1.1 years. Mean intraocular pressure decreased from 30.4 +/- 8.4 mmHg preoperatively to 13.8 +/- 5.0 mmHg at last follow-up(p <0.001). The mean number of ocular hypotensive medications decreased from 3.7 +/- 0.8 preoperatively to 0.4 +/- 1.0 at last follow-up (p <0.001). At last follow-up, the complete success, qualified success, and failure rates were 73.7%, 10.5%, and 15.8% ,respectively.No canaloplasty-related permanent sight-reducing complications occurred. Preoperative best corrected visual acuity decreased more than 1 Snellen line in 1 eye due to exacerbation of uveitis 18 months postoperatively. Conclusions: Canaloplasty appears to be a relatively safe and effective initial surgical intervention in UG.
As president and leader of the American Glaucoma Society, Dr Singh wears many hats that serve the glaucoma community. It is his job to point out areas of concern and express his opinion. However, the ability to perform cataract and microinvasive canal
surgery through the same incision is a long-awaited affair. The ability to improve vision, increase flow into the patient’s natural collector system (instead of a bleb), prevent detrimental postoperative IOP spikes (cataract surgery does not), and reduce IOP
and medication burden for several years is nothing short of a miracle for our patients. Even though we do not have an outcome marker to measure aqueous venous outflow, progress in this field is happening with much more to come. Dr Singh rightfully forecasts the “perfect storm” and we have heeded his warning. Our task is to be aware of his prediction and practice evidence-based medicine in tandem with the ethical standards of the Hippocratic oath
Canaloplasty is a new nonperforating surgical technique for open-angle glaucoma, in which a microcatheter is inserted within Schlemm’s canal for the entire 360 degrees. A 10-0 prolene suture, which is tied to the distal tip of the microcatheter, is then positioned and left tensioned in Schlemm’s canal, thus facilitating aqueous outflow through natural pathways. A small amount of viscoelastic agent is delivered in Schlemm’s canalwhile the catheter is withdrawn.Themid-termresults are very promising. Based on
our cohort of 214 patients, the percentages of eyes that obtained postoperative IOP≤ 21mmHg, ≤18mmHg, and ≤16mmHg with or without medical therapy after 2 and 3 years were 88.7%, 73.7%, and 46.2% (2 years); 86.2%, 58.6%, and 37.9% (3 years), respectively. The most frequent complications observed included hyphema; descemet membrane detachment; IOP spikes; and hypotony. The advantages of canaloplasty over trabeculectomy include (1) no subconjunctival bleb; (2) no need for antimetabolites; (3) fewer postoperative complications; and (4) a simplified follow-up. The disadvantages include the following: (1) a long and rather steep surgical learning curve; (2) the need of specific instruments; (3) average postoperative IOP levels tend not to be very low; and (4) impossibility to perform the entire procedure in some cases.
At the 2 year follow-up, both techniques were efficient in controlling IOP, providing mean values in the low-mid teens However canaloplasty enables a higher independence of medical treatment and higher complete success rates.
OBJECTIVE: To compare the safety and efficacy between canaloplasty and aqueous drainage pathway reconstruction surgery in patients with open-angle glaucoma (OAG).
METHODS: It is a retrospective case series study. Thirty-one eyes (25 patients) with OAG were divided into canaloplasty (n = 17; 54.8%) group or aqueous drainage pathway reconstruction (n = 14; 45.2%) group. The intraocular pressure (IOP), numbers of IOP-lowering medications and incidence of complications were recorded at 1 day, 1 week, 1, 3, 6 and 12 months after the operation. Independent-samples T test was used to compare the IOP, numbers of IOP-lowering medications before and 1, 3, 6, 12, 24 months after surgery between two groups. Kaplan-Meier Survival Analysis was used to analyze the success rate of these two surgical methods. Log rank test was used to compare the difference of cumulative success rate at 6, 12 months after surgery.
RESULTS: The mean IOP values were (24.7 ± 8.7) , (14.5 ± 2.5), (14.9 ± 2.5) , (14.9 ± 2.5), (14.7 ± 2.1) and (15.4 ± 2.3) mmHg (1 mmHg = 0.133 kPa) in canaloplasty group at before surgery, 1, 3, 6, 12 and 24 months after surgery. The same values were (28.5 ± 10.6), (14.3 ± 3.6), (14.2 ± 3.2), (14.3 ± 3.6), (15.9 ± 3.2) and (14.6 ± 0.7) mmHg in aqueous drainage pathway reconstruction group. There was no difference in the extent of IOP reduction between these two groups (preoperative: t = -1.1014, P = 0.278; postoperative 1 month: t = 0.696, P = 0.492;3 month: t = 0.594, P = 0.557; 6 month: t = 0.536, P = 0.596; 12 month:
t = -1.127, P = 0.273; 24 month: t = 0.455, P = 0.656). There were significant differences (P < 0.01) in post-surgery IOP lowering medication usage between these two groups, while pre-surgery medication usage were similar. The incidence of hyphema was significantly lower in aqueous drainage pathway reconstruction surgery group (2 eyes) than that in canaloplasty group (11 eyes).
CONCLUSIONS: Both canaloplasty and aqueous drainage pathway reconstruction could reduce IOP effectively for open-angle glaucoma. The incidence of complication was lower in the aqueous drainage pathway reconstruction group than canaloplasty group. However, long-term efficacy between these two groups is yet to be determined
Purpose: To present the mid-term results of a prospective multicenter study on canaloplasty surgery in chronic open-angle glaucoma. Materials and Methods: A total of 218 eyes from 197 patients with open-angle glaucoma under maximum tolerated medical therapy underwent canaloplasty within a time period of 42 months in 3 different Italian eye centers. All patients underwent a complete ophthalmic examination every 6 months. The follow-up ranged from 3 to 42 months. Results: The entire procedure according to standard protocol could not be performed in 20 eyes (9.2%). A total of 198 eyes from 178 patients with a mean follow-up of 23.1±10.6 months were taken into consideration. The preoperative mean intraocular pressure (IOP) was 28.4±7.5mm Hg. The mean IOP at the 2-year followup was 15.9±4.7mm Hg (range, 6 to 40mm Hg; paired t test; P=0.0001), with a mean reduction from baseline of 44% (range, 11.1% to 82.8%). After 2 years of follow-up, a qualified success rate based on postoperative IOPr21, r18, and r16mm Hg was obtained in 82 (92.1%), 75 (84.3%), and 61 (68.5%) eyes, respectively; a complete success for an IOPr21, r18, and r16mm Hg was obtained in 63 (70.8%), 60 (67.4%), and 53 (59.5%) eyes, respectively. The number of medications used preoperatively and at the 2-year follow-up was 3.2±0.9 and 1.1±1.3, respectively. The most frequently seen complications included: hyphema in 47 eyes (23.7%), Descemet membrane detachment in 11 eyes (5.5%), and IOP spikes >10mm Hg in 12 cases (6.1%). Conclusions: Canaloplasty is a quite difficult surgical technique; however, mid-term results are promising. Complications can sometimes occur, but are seldom serious. The main advantage of this promising bleb-less procedure is that physiological humor aqueous outflow is restored.
Conclusion: Canaloplasty reduced the intraocular pressure and postoperative antiglaucomatous medication in both groups statistically significant. Eyes having preoperative laser trabeculoplasty showed a tendency to higher resistance and misdirection of the microcatheter during canaloplasty. Laser induced scarring of the TMW may cause those difficulties while probing. There is no statistically difference between these two groups relating to postoperative IOP and intraoperative complications, which might be caused by the retrospective studydesign with a small studypopulation
Purpose: To compare the safety, efficacy, and postoperative management of canaloplasty in one eye versus trabeculectomy with mitomycin C in the contralateral eye in patients with open-angle glaucoma. Methods: This study was a consecutive case series of 30 eyes of 15 patients who had prior trabeculectomy with mitomycin C (group II) and later were treated with canaloplasty (group I) in the felloweye. Primary outcome measures included intraocular pressure (IOP) and glaucoma medication after 6- and 12-month follow-up. Secondary outcome measures were number of postoperative interventions, hospitalization, and follow-up visits. Methods: This study was a consecutive case series of 30 eyes of 15 patients who had prior trabeculectomy with mitomycin C (group II) and later were treated with canaloplasty (group I) in the fellow eye. Primary outcome measures included intraocular pressure (IOP) and glaucoma medication after 6- and 12-month follow-up.Secondary outcome measures were number of postoperative interventions, hospitalization, and follow-up visits. Results: Mean preoperative IOP±SD was 26.73±6.4mm Hg in group I and 26.3±10.9mm Hg in group II (P=0.9), which decreased to 13.21±2.83mm Hg for canaloplasty (P<0.0001)and 11.64±5.2mm Hg for trabeculectomy (P<0.0005) including 3 patients with hypotony at 12 months. Glaucoma medication decreased from 2.5 in group I and 2.7 in group II to no medication in group I and 0.36±0.74 supplemental medication in group II 12 months postoperatively (P<0.0001). Best corrected visual acuity (±SD) was logMAR 0.06±0.09 (group I) and 0.28±0.56 (group II) before and logMAR 0.07±0.09 (group I) and 0.31±0.58 (group II) after surgery. In group I, 2 interventions were necessary. In group II, 8 eyes needed 112 interventions for filtering bleb management. Although canaloplasty took significantly longer to perform, trabeculectomy group required a longer initial postoperative hospitalization (mean 10.4 vs. 5.4 d, P<0.0001) and more postoperative follow-up visits (mean 3.9 vs. 8.5, P<0.001). Conclusions: Canaloplasty and trabeculectomy were both effective in lowering IOP. However, less follow-up visits and significantly fewer complications and interventions were favorable for canaloplasty.
Laser goniopuncture is a complementary adjunct to nonfiltering glaucoma surgery such as deep sclerectomy, viscocanalostomy, and canaloplasty, contributing to intraocular pressure control and the avoidance of additional incisional surgery. Goniopuncture is associated with a low complication rate and demonstrates minimal inflammation, hemorrhage, and hypotony when performed correctly. This article provides a detailed description of how to perform this procedure and methods of preventing and addressing complications.
Commercial non-degradable glaucoma implants are often associated with undesired hypotony, fibrosis, long termfailure, and damage of adjacent tissues,which may be overcome by a multifunctional polymeric microstent for suprachoroidal drainage. This study reports the design and fabrication of such deviceswith tailorable internal diameters (50–300μm) by solvent-free, continuous hot melt extrusion fromblends of poly[(ε-caprolactone)-coglycolide] and poly(ε-caprolactone) [PCL]. A spatially directed release was supported by bilayered microstents with an internal drug-free PCL layer, and a quantitative description of release kinetics with diclofenac sodium as model drug was provided. Furthermore, the slow degradation pattern (N1 year) was analyzed and potential effects of 1–5wt.% drug loading on material properties were excluded. Translational aspects including sterilization by γ-irradiation on dry ice, in vitro biocompatibility, and in vivo implantation were addressed. The promising results support further functional analysis of long-termin vivo performance and suppression of disadvantageous capsule formation.
Purpose: To report 3-year results evaluating the effect on safety and efficacy of canaloplasty to treat open-angle glaucoma when combined with cataract surgery.
Patients and Methods: This was a retrospective subset analysis of a prospective, international, multicenter study evaluating 133 eyes of 133 adult, open-angle glaucoma patients who underwent canaloplasty with tensioning suture placement. Eighty-two phakic eyes that received canaloplasty alone were compared with 51 eyes that
underwent cataract surgery before or during canaloplasty. Results: Phakic eyes that received combined cataract-canaloplasty surgery (phacocanaloplasty) had a mean±SD baseline IOP of 23.5±5.2mm Hg and mean glaucoma medication usage of 1.5±1.0 decreasing to a mean IOP of 13.6±3.6mm Hg on 0.3±0.5 medications at 3 years postoperatively. Pseudophakic eyes undergoing canaloplasty had a mean baseline IOP of
23.9±5.2mm Hg on a mean of 1.8±0.8 glaucoma medications decreasing to 15.6±3.5mm Hg on 1.1±0.8 medications at 3 years. In phakic eyes, reductions in IOP were significantly greater and less postoperative IOP lowering medication was needed after
undergoing phacocanaloplasty compared to eyes which had canaloplasty alone.
Conclusions: Clear corneal phacoemulsification performed before or in combination with canaloplasty is a safe and effective surgical procedure to reduce IOP in adult patients with open-angle glaucoma.
Canaloplasty surgery was carried out, and patients were followed-up for 3 months where all clinical indices were assessed. Additional SLT procedure was conducted to those who failed to achieve the target reduction of IOP. Patients were followed-up again for approximately 3 months for confirmation of success. Six eyes of 4 patients were consecutively recruited in the current study (2 bilateral and 2 unilateral). TheCombining both interventions, the mean overall decrease in IOP from its baseline value of 23.5 ± 3.9 mm Hg to its final value of 13.8 ± 1.7 mm Hg was 9.7 mm Hg (41.3%), which was statistically significant
Canaloplasty, a recently developed nonpenetrating glaucoma surgical approach, may restore physiological outflow routes in primary open-angle glaucoma with less risk of
severe postoperative complications than trabeculectomy. Since the inner wall of
Schlemm’s canal (SC) is directly in contact with the trabecular meshwork (TM) for 3608
and the catheter device used in canaloplasty allows viscoelastic to be injected into the
entire length of SC, canaloplasty might also be used to perform SC/TM-targeted
delivery of transgene vectors for glaucoma gene therapy. This hypothesized new
method for transgene delivery may give the transgene access to the entire inner wall
of SC and the whole juxtacanalicular region of the TM and allow the transgene to be
expressed in both the TM and SC without affecting the cornea, iris, and ciliary body.
This strategy might have a greater trabecular outflow resistance-decreasing effect
than either the genetic or surgical approach alone.
.......Although all novel glaucoma procedures seem better with cataract surgery, some are undoubtedly better than others. Purists may insist that evaluation of any novel glaucoma procedure being proposed as an adjunct to cataract surgery should also be studied as a stand-alone glaucoma operation so as to not conceal the possible lack of efficacy of the novel therapy, with adjunctive phacoemulsification. Nevertheless, it is hard to argue against the benefit of a safe glaucoma procedure that can lower IOP 2e3 mmHg beyond phacoemulsification alone in a substantial proportion of those being treated, regardless of how ineffective the procedure may be as a stand-alone operation. There should be some minimum standard for additivity, comparable with that used in assessing glaucoma medications used adjunctively with gold standards such as prostaglandin analogs, for us to adopt novel glaucoma operative procedures combined with cataract surgery. Just as adding third and fourth glaucoma medications for IOP lowering may not be justified from a riskebenefitecost standpoint, proceeding with glaucoma surgical option with a very low likelihood of additivity to cataract surgery alone will, at the very least, unnecessarily add to health care costs, and in the worse case, put patients at risk that is not justified by the potential benefit.
Purpose: To assess risk factors for failure in canaloplasty. Methods: Nonrandomized prospective study involving 51 eyes of 51 patients with medically uncontrolled primary open-angle glaucoma undergoing canaloplasty. Visual acuity, intraocular pressure (IOP) and slit-lamp examinations were performed before and after surgery at 1 and 7 days, and at 1 month and every 3 months thereafter. Factors like age, gender, preoperative IOP and microhyphema on day 1 were evaluated. Results: The mean follow-up was 20.6 (SD 8.3) months. The mean preoperative IOP was 26.8 (SD 5.2) mmHg; the mean postoperative IOP was 8.4 (4.2) mmHg at day 1 and 12.7 (1.7) mmHg at month 24. Microhyphema was found in 40 patients (85.1%) on day 1 after surgery. The height of microhyphema was 1.8 mm ± 0.4 (SD) (range 1–2.5), and the time of resorption was 6.6 days ± 2.8 (SD) (range 3–14) on average. No recurrence of hyphema has been observed. IOP < 16 mmHg without medications depended significantly on the presence of microhyphema (hazard ratios, HR 0.03, 95% CI 0.01–0.25, p < 0.001), but not on age (HR 1.00, 95% CI 0.91–1.09, p = 0.32), preoperative IOP (HR 0.98, 95% CI 0.85–1.12, p = 0.80), cup-to-disc ratio (HR 0.15, 95% CI 0.00–20.01, p = 0.45) and gender (HR 0.24, 95% CI 0.05– 1.12, p = 0.07). Factors like preoperative IOP, age, gender, cup-to-disc ratio were not associated with microhyphema. There were no significant differences between patients with versus without microhyphema in regard to age, preoperative IOP, morphological and functional glaucomatous damage, number of medications and postoperative day 1 IOP. However, patients with microhyphema had significantly fewer Nd:YAG goniopunctures after surgery than patients without microhyphema (p < 0.001). Conclusion: Microhyphema the first postoperative day seems to be a significant positive prognostic indicator in uneventful canaloplasty in regard to IOP reduction, possibly representing a restored and patent physiologic aqueous outflow system.
Purpose: To evaluate the safety and preliminary efficacy of intraoperative mitomycin C (MMC) in conjunction with canaloplasty for the treatment of open-angle glaucoma.
Methods: Observational case series. A microcatheter was used to viscodilate the full circumference of Schlemm canal and to place a trabecular meshwork tensioning suture. Low dosage MMC was applied beneath the superficial scleral flap before dissecting the
second, deep scleral flap and accessing Schlemm canal. Qualifying preoperative intraocular pressures (IOPs) were at least 16mm Hg with a historical maximum IOP of at least 21mm Hg. Primary outcome measures including visual acuity and adverse events are
reported for a 12-month postoperative period. Secondary outcome measures included IOP and glaucoma medication usage.
Results: In 20 eyes of 20 consecutive patients, adverse events were generally transient and not sight threatening. With the use of MMC, there was an increased rate of hypotony as compared with reported results of prior canaloplasty studies. The mean logMAR
best corrected visual acuity at baseline was 0.07±0.12 with a mean of 0.09±0.13 at 12 months (P=0.679). Mean IOP decreased from a preoperative value of 23.4±4.3mm Hg on 2.2±1.2 antiglaucoma medications to 13.4±4.3mm Hg on no medications at 12 months. At all intervals, IOP and medication use results were significantly reduced versus baseline (P<0.001).
Conclusions: The adjunctive use of MMC in canaloplasty is safe and effective.
Purpose: To study the impact of benzalkonium chloride (BAK) exposure from eye drops on subsequent time to trabeculectomy failure.
Patients and Methods: Retrospective chart review of 128 glaucoma patients who had undergone a trabeculectomy between 2004 and 2006. The number and type of ophthalmic drops used preoperatively and relevant demographics were recorded. Surgical
failure criteria included inadequate pressure lowering or need for postoperative ocular antihypertensives, laser trabeculoplasty, 5-fluorouracil needling, or repeated surgery. Patients were examined for these criteria over a minimum postoperative period of 2
years. Data were assessed using Kaplan-Meier and Cox regression models. Results: Complete surgical success was achieved in 47.7% of patients. Patients received between 1 and 8 BAK-containing drops daily, with a median of 3. Time to surgical failure in patients receiving higher preoperative daily doses of BAK was shorter than in patients who had less BAK exposure (P=0.008). Proportional hazard modeling identified uveitic and neovascular glaucoma as significant confounders of the univariate model (P=0.024), although the main effect of BAK exposure was maintained with a hazard ratio of 1.21 (P=0.032). The number of different medications used to control intraocular pressure did not significantly affect survival time in a secondary Cox model (P=0.948).
Conclusions: Increased preoperative exposure to ophthalmic solutions preserved with BAK is a risk factor for earlier surgical failure, independent of the number of medications used. This study extends earlier findings of potential adverse effects of ophthalmic preservatives on surgical outcomes to the modern pharmacopeia used in the medical management of glaucoma.
Background: Cataract and glaucoma are both common comorbidities among older patients. Combining glaucoma surgery with minimal invasive phacoemulsification (phaco) is a considerable option to treat both conditions at the same time, although the combination with filtration surgery can produce a strong inflammatory response. Combined non-penetrating procedures like canaloplasty have shown to reduce intraocular pressure (IOP) comparable to trabeculectomy without the risk of serious bleb-related complications. The purpose of this retrospective study was to compare the outcomes of phacotrabeculectomy and phacocanaloplasty. Methods: Thirty-nine eyes with concomitant cataract and glaucoma who underwent phacotrabeculectomy (n = 20; 51.3%) or phacocanaloplasty (n = 19; 48.7%) were included into this trial on reduction of IOP, use of medication, success rate, incidence of complications and postsurgical interventions. Complete success was defined as IOP reduction by 30% or more and to 21 mmHg or less (definition 1a) or IOP to less than 18 mmHg (definition 2a) without glaucoma medication. Results: Over a 12-month follow-up, baseline IOP significantly decreased from 30.0 ± 5.3 mmHg with a mean of 2.5 ± 1.2 glaucoma medications to 11.7 ± 3.5 mmHg with a mean of 0.2 ± 0.4 medications in eyes with phacotrabeculectomy (P < .0001). Eyes with phacocanaloplasty had a preoperative IOP of 28.3 ± 4.1 mmHg and were on 2.8 ± 1.1 IOP-lowering drugs. At 12 months, IOP significantly decreased to 12.6 ± 2.1 mmHg and less glaucoma medications were necessary (mean 1.0 ± 1.5 topical medications; P < .05). 15 patients (78.9%) with phacotrabeculectomy and 9 patients (60.0%) in the phacocanaloplasty group showed complete success according to definition 1 and 2 after 1 year (P = .276). Postsurgical complications were seen in 7 patients (36.8%) of the phacocanaloplasty group which included intraoperative macroperforation of the trabeculo-Descemet membrane (5.3%), hyphema (21.1%) and bleb formation (10.5%). Although more complications were observed in the phacotrabeculectomy group, no statistically significant difference was found. Conclusions: Phacocanaloplasty offers a new alternative to phacotrabeculectomy for treatment of concomitant glaucoma and cataract, although phacotrabeculectomy yielded in better results in terms of IOP maintained without glaucoma medications.
Purpose: To identify changes in visual acuity and intra-ocular pressure (IOP) 12 months after the development of bleb-related infection.
Methods: Data obtained from 146 eyes of 146 patients with bleb-related infection were analyzed as a part of the Japan Glaucoma Society Survey of Bleb-related Infection. Multiple logistic regression analysis was conducted to identify factors associated with poor
prognosis in visual acuity and increased IOP and for being stage III. Results: The logMAR increased by a mean of 0.140, 0.440, 1.099 and 1.122 at 12 months postinfection for stage I, II, IIIa and IIIb infections, respectively. The logMAR was significantly worse at 6 and 12 months postinfection in stage IIIb (p = 0.002 andp = 0.003, respectively; Wilcoxon signed-rank test) and at 6 months postinfection instage IIIa (p = 0.036). The IOP was significantly elevated following infection in bothstage IIIa and stage IIIb (p = 0.028 and p = 0.008 at 6 and 12 months, respectively, forstage IIIa; p = 0.002 and p = 0.005 for stage IIIb). The multiple logistic regressionanalysis revealed that being stage III and positive culture were significant risk factors for poor outcome for visual acuity (Odds ratio: 9.26 and 6.29, respectively) and that beingstage III was a prognostic factor for increased IOP (Odds ratio: 8.33). Pseudophakia oraphakia was significantly associated with stage III and stage IIIb infections (Odds ratio:2.85 and 6.30). Conclusions: Stage III bleb-related infection causes significant visual loss and IOPelevation within 12 months after development. Therefore, preventative measuresshould be taken, especially in cases that are pseudophakic or aphakic.
PURPOSE: To report the risk of endophthalmitis and other long-term complications in patients randomized to trabeculectomy in the Collaborative Initial Glaucoma Treatment Study. DESIGN: A longitudinal cohort study using data collected from a multicenter, randomized clinical trial. METHODS: Long-term postoperative complications in
the 300 patients randomized to trabeculectomy in the Collaborative Initial Glaucoma Treatment Study were tabulated. Kaplan-Meier analyses were used to estimate the time-related probabilities of blebitis, hypotony, and endophthalmitis.
RESULTS: Two hundred eighty-five patients were included in the final trabeculectomy cohort after accounting for declining treatment assignment and other early events. Patients were followed up for an average of 7.2 years. One hundred sixty-three patients (57%) received 5-fluorouracil during surgery. Of the 247 patients with at least 5 years of follow-up, 50required further treatment for glaucoma. Cataract extractionwas performed in 57 patients (20%). Forty patients(14%) required bleb revision at least once. Bleb-related complications included bleb leak (n [ 15), blebitis (n [ 8), and hypotony (n [ 4). Three patients werenoted to have endophthalmitis, although the diagnosisin 2 patients was presumptive. The occurrences of blebitis, hypotony, or endophthalmitis were not significantly associated with 5-fluorouracil use. The Kaplan-Meiercalculated risks of blebitis and hypotony at 5 years wereboth 1.5%, whereas the risk of endophthalmitis was1.1%. CONCLUSIONS: The potential efficacy of trabeculectomy must be weighed against the long-term risk ofcomplications, especially endophthalmitis, when selecting treatments for patients with open-angle glaucoma.We report a low 5-year risk of endophthalmitis (1.1%) and other bleb-related complications in the trabeculectomy cohort of the Collaborative Initial Glaucoma Treatment Study.
Purpose: To study the efficacy and the safety of ultrasound biomicroscopy assisted canaloplasty in the treatment of open-angle glaucoma (OAG). Methods: A prospective study of uncontrolled open-angle glaucoma patients, or patients with cataracts associated with controlled or uncontrolled OAG under maximal medical therapy who had been subjected to canaloplasty alone or combined with cataract surgery, respectively. Complications, Goldmann intraocular pressure (IOP) and mean number of drugs(ND) were evaluated at 1 day, 1 week, 1 month, and every 3 months. Results: Thirty five surgeries were performed (11 canaloplasties, 24 phaco-canaloplasties). The mean IOP (mmHg) dropped from 24.5± 5.1, in canaloplasty, and from 19.8 ± 6.4, in phacocanaloplasty, preoperatively, to medium-low levels at all follow-up periods (13.5 ± 1.0 and 11.0 ± 4.2, at 1 year in canaloplasty and phaco-canaloplasty, respectively). The number of grugs used dropped from 3.3 ± 0.5 before surgery to less than of 1 in all follow-up periods (0.5 ± 0.8 at 1 year). The complications were 2 microruptures of the trabeculodescemetic window, 5 entries in the collector channels, 5 choroidal space/anterior chamber passages, 10 hyphemas, 3 hypotonies, one peripheral Descemet detachment, one intracorneal hematoma, two peripheral anterior synechia, one internal iris prolapse, and two suture extrusions to the anterior chamber. Conclusions: Ultrasound biomicroscopy assisted Canaloplasty, alone or combined, provided a sustained IOP reduction to medium-low levels, led to a decrease in the number of drugs and had a good safety profile, making this a good alternative to trabeculectomy.
We thank Maurizio Gismondi and Paolo Brusini for their interest in our case and the interesting comments. We agree that the procedure to remove the intracorneal hematoma should be performed as soon as possible in orderto avoid permanent tattooing. In our case, the reason for an unsatisfying best-corrected visual acuity was not clearly distinguishable between a strong fibrinous reaction in the anterior chamber, mydriasis, or the intracorneal hematoma. Therefore the intervention was performed 4 days
postoperatively after the intracorneal hematoma showed no tendency of reabsorption. Since this case, we have seen further patients with similar complications during viscocanaloplasty, where the procedure was successfully performed immediately after or during surgery. Using the same technique, intracorneal viscoelastics (Healon GV®, (Abbott Laboratories Inc., Abbot Park, Illinois, USA) were successfully removed intraoperatively.
Objective: To evaluate the efficacy and safety of current trabeculectomy surgery in the United Kingdom. Design: Cross-sectional, multicenter, retrospective follow-up.
Participants: A total of 428 eyes of 395 patients.
Methods: Consecutive trabeculectomy cases with open-angle glaucoma and no previous incisional glaucoma surgery from 9 glaucoma units were evaluated retrospectively. Follow-up was a minimum of 2 years.
Main Outcome Measures: Surgical success, intraocular pressure (IOP), visual acuity, complications, and interventions. Success was stratified according to IOP, use of hypotensive medications, bleb needling, and resuturing/ revision for hypotony. Reoperation for glaucoma and loss of perception of light were classified as failures. Results: Antifibrotics were used in 400 cases (93%): mitomycin C (MMC) in 271 (63%), 5-fluorouracil (5-FU) in 129 (30%), and no antifibrotic in 28 (7%). At 2 years, IOP (mean standard deviation) was 12.4 4 mmHg, and 342 patients (80%) achieved an IOP 21 mmHg and 20% reduction of preoperative IOP without IOP-lowering medication, whereas 374 patients (87%) achieved an IOP 21 mmHg and 20% reduction of preoperative IOP overall. An IOP 18 mmHg and 20% reduction of preoperative IOP were achieved by 337 trabeculectomies (78%) without IOP-lowering treatment and by 367 trabeculectomies (86%) including hypotensive medication. Postoperative treatments included suture manipulation in 184 patients (43%), resuturing or revision for hypotony in 30 patients (7%), bleb needling in 71 patients (17%), and cataract extraction in 111 of 363 patients (31%). Subconjunctival 5-FU injection was performed postoperatively in 119 patients (28%). Visual loss of >2 Snellen lines occurred in 24 of 428 patients (5.6%). A total of 31 of the 428 patients (7.2%) had late-onset hypotony (IOP 2 Snellen lines. Bleb leaks were observed in 59 cases (14%), 56 (95%) of which occurred within 3 months. Two patients developed blebitis. Bleb-related endophthalmitis developed in 1 patient within 1 month postoperatively and in 1 patient at 3 years. There was an endophthalmitis associated with subsequent cataract surgery.
Conclusions: This survey shows that good trabeculectomy outcomes with low rates of surgical complications can be achieved, but intensive proactive postoperative care is required
The authors indicate four key issues which, in their opinion, represent the most stimulating challenges in the field of glaucoma today, and describe the present approaches and the developments that can be expected or advised in the near future: (1) Glaucoma is often undiagnosed or diagnosed too late. Accurate detection is crucial to correctly recognize and treat affected subjects, thus reducing the disability and the social burden of the disease. Is glaucoma screening advisable and cost-effective? What strategies can be implemented to achieve an earlier diagnosis? (2) What role can genetics play in glaucoma clinics? (3) What are the fundamentals and the limits of medical hypotensive and nonhypotensive treatment of glaucoma today, and what novelties could be introduced in the next few years? (4) What are the current and future options for glaucoma surgery? Should we aim at reducing aqueous production or at enhancing aqueous outflow? What are the success figures and the pros and cons of ab externo procedures with external filtration (trabeculectomy, nonpenetrating techniques and glaucoma drainage devices) and of ab externo techniques with internal filtration (viscocanalostomy and canaloplasty)? Will microinvasive procedures ever play a role in the treatment of the disease? These questions and the possible future developments in the management of glaucoma are discussed critically, based on the current clinical state of the art, on a review of the literature, and on an everyday experience in a busy university hospital glaucoma service.
The article by Freiberg et al (1) reports an interesting case of intracorneal hematoma after canaloplasty. We published an analogous case in 2011 in Cornea, which
reported a similar surgical approach (2). Descemet membrane detachment is unusual, but can occur in cases after canaloplasty. In our cohort of 198 eyes, such a finding was observed in 11 eyes (5.5%) (3). The mechanism that leads to this complication, as correctly suggested by the authors, is probably related to the injection of a highmolecular-
weight viscoelastic material in the Schlemm canal, especially if this maneuver is done while advancing the microcatheter with some encountered obstacle in the Schlemm canal. In these cases, the viscoelastic tends to break the Schwalbe line, producing a detachment
of the Descemet membrane. The detachment can be filled by blood arising from the Schlemm canal. Usually the blood tends to reabsorb within a few weeks without any visual impairment. However, when the intracorneal hematoma is symptomatic, it is advisable to
remove the blood by partial-thickness paracentesis, without interrupting the Descemet membrane (2). This procedure should be performed as soon as possible in order to avoid the settling of blood, which can lead to permanent tattooing of the corneal tissue.
Purpose: To evaluate efficacy and survival rates of intraocular pressure (IOP)-lowering effect obtained with phacoemulsification (phaco) alone or in combination with canaloplasty (PCP) chronic uveitis, angle-closure glaucoma, and advanced-stage or patients with open-angle glaucoma (OAG). Methods: Retrospective chart review of consecutive cases at the Department of Ophthalmology, Indiana University. Visual acuity (VA), IOP, number of medications (Meds), failures, and survival rates of IOP-lowering effect were analyzed. Inclusion criteria were: patients older than 18 years with OAG and cataract. Exclusion criteria were: no light perception vision, prior glaucoma surgery, end-stage OAG. Failure criteria were: IOP>21mm Hg or <20% reduction, IOP<6mm Hg, further glaucoma surgeries, and loss of light perception vision. Results: Thirty-seven patients underwent phaco and 32 patients had PCP. Follow-up was 21.8±10.1 versus 18.8±9.6 months for phaco and PCP, respectively (P=0.21). Age (y) (74.7±9.8 vs. 76.1±8.3, P=0.54), sex (P=81), and laser status (P=0.75) were similar between the groups. Preoperatively, mean±SD logMAR VA (0.5±0.7 vs. 0.5±0.5, P=0.77), IOP (16.2±4.6 vs. 18.2±5.1, P=0.13), and Meds (1.4±1.1 vs. 1.3±0.7, P=0.75) were similar for phaco and PCP, respectively. At 24-month phaco (n=17) and PCP (n=11), respectively, mean±SD were: logMAR VA 0.2±0.2 versus 0.4±0.7, P=0.29; IOP 14.1±4.0 versus 12.9±3.8, P=0.43; and Meds 1.5±1.2 versus 0.3±0.5 P=0.005. Rates of successful IOP lowering without medications for phaco versus PCP at 12 months were 34% versus 75%, respectively (P=0.003) Conclusions: A combination of canaloplasty with phaco results in a decreased number of glaucoma medications and increased survival rate of IOP-lowering effect compared with phaco alone.
Currently, there are numerous choices for the treatment of pediatric glaucoma depending on the type of glaucoma, the age of the patient, and other particularities of the condition discussed in this review. Traditionally, goniotomy and trabeculotomy ab externo have been the preferred choices of treatment for congenital glaucoma, and a variety of adult procedures adapted to children have been utilized for other types of pediatric glaucoma with variable results and complications. More recently, seton implantations of different types have become more popular to use in children, and newer techniques have become available including visualized cannulation and opening of Schlemm’s canal, deep sclerectomy, trabectome, and milder more directed cyclodestructive procedures such as endolaser and transcleral diode laser cyclophotocoagulation.This paper reviews the different surgical techniques currently
available, their indications, results, and most common complications to allow the surgeon treating these conditions to make a more informed choice in each particular case. Although the outcome of surgical treatment in pediatric glaucoma has improved significantly, its treatment remains challenging.
Purposes: To describe a case of hemorrhagic Descemet membrane detachment following canaloplasty and to discuss its management using neodymium:yttrium-aluminum-garnet (Nd:YAG) laser Descemet membranotomy. Methods: Interventional case report. Results: A 71-year-old woman with chronic open-angle glaucomadeveloped a hemorrhagic Descemet detachment after combined phacoemulsification, intraocular lens insertion, and canaloplasty. The hematoma did not improve with initial expectant management. Two and a half weeks after surgery, the Nd:YAG laser was applied to create a break in the Descemet membrane in the region of the hematoma. The intracorneal blood quickly dissipated into the anterior chamber. Visual acuity improved to 20/20. The endothelial cell count was 2342 cells per square millimeter 4 years after the surgery. Pachymetry did not show any long-term alterations as a result of the Nd:YAG treatment. Conclusions: Hemorrhagic Descemet detachment is an uncommon complication after canaloplasty. Nd:YAG Descemet membranotomy is a successful means of clearing the hematoma and thus can prevent further complications, such as corneal blood staining.
Purpose: To study the epidemiology and risk factors of early- and late-onset postoperative endophthalmitis (PE) and severe blebitis following trabeculectomy. Methods: Retrospective, single-centre, observational study with a case–control design in part. Patients sustaining PE and severe blebitis following trabeculectomy or a combined trabeculectomy with a cataract extraction procedure
performed from 1990 through 2008 and diagnosed from 1990 through 2012 were recorded at St Erik Eye Hospital. Incidence data were calculated with help from the hospital records. Notes data of cases and of six randomly selected but procedure matched control patients for each case were compared. Results: The joint rate of infection was 0.46% or 34 incidents in 7402 procedures. The frequency of early (occurring <6 weeks after surgery) onset PE was 0.19%, late PE was 0.19% and severe blebitis was 0.08%. Dominating aetiologies were staphylococci and streptococci. Overall, the infection severely impaired the visual function. Combined cataract and fistulating operations were less prone to develop late infections, p = 0.04, but no other decisive factors were identified in the case–control study. Data collection for all trabeculectomy surgeries from 1998 and onward identified an increased rate for late infection with the use of mitomycin C (MMC), 8 in 1171 surgeries or 0.7%, versus no such use, 0 case of late PE in 2136 surgeries, p < 0.001. Conclusions: Postoperative endophthalmitis is a devastating complication after trabeculectomy. The use of MMC increases the risk for delayed infection. Early PE after trabeculectomy is clearly more common than PE after cataract surgery. Developing efficacious prophylactic antibiotic regimens to reduce early PE after penetrating filtering procedures should be a major priority in ophthalmic surgery.
IMPORTANCE To date, only a few studies have directly compared nonpenetrating surgery (NPS) and trabeculectomy (TE). Therefore, there is no strong evidence as to which surgical technique leads to the best results in terms of ocular hypotensive effect and safety. OBJECTIVE To compare the hypotensive effect and safety of NPS and TE in terms of intraocular pressure (IOP) reduction and incidence of complications. DATA SOURCES The MEDLINE and EMBASE: Databases were searched for studies potentially eligible in any language published up to March 31, 2013. STUDY SELECTION Systematic review and meta-analysis of comparative studies of 2 or more surgical techniques (1 of which had to be TE), including patients with open-angle glaucoma. DATA EXTRACTION AND SYNTHESIS The considered interventions were TE, deep sclerectomy (DS), viscocanalostomy, and canaloplasty. MAIN OUTCOMES AND MEASURES The primary outcomewas the mean between-group difference in the reduction in diurnal IOP from baseline to the 6- or 12-month follow-up evaluation.We also considered the incidence of complications, expressed as relative risk. RESULTS Eighteen articles, accounting for 20 comparisons, were selected for data extraction and analysis. Analysis of the 6-month follow-up data showed that the pooled estimate of the mean between-group difference was −2.15mmHg (95%CI, −2.85 to −1.44) in favor of TE. There was no difference between the NPS subgroups. In the subgroup antimetabolite analysis, the addition of mitomycin C to TE and DS decreased the difference in the reduction in IOP (TE and DS without mitomycin C: −2.65mmHg [95%CI, −3.90 to −1.39]; TE and DS with mitomycin C: −0.83mmHg [95%CI, −2.40 to 0.74]). In the subgroup analysis by implant addition, no significant difference induced by DS with or without drainage devices was detected (test for subgroup differences: χ2 1 = 0.24; P = .62). The absolute risk of hypotony, choroidal effusion, cataract, and flat or shallow anterior chamber was higher in the TE group than in the NPS group. CONCLUSIONS AND RELEVANCE Trabeculectomy seems to be the most effective surgical procedure for reducing IOP in patients with open-angle glaucoma. However, as expected, it was associated with a higher incidence of complications when compared with NPS.
In a 71-year-old patient with bilateral open-angle glaucoma, intracorneal blood was found after a canaloplasty procedure in the right eye. Six weeks after surgery on ultrasound biomicroscopy examination, liquified blood and blood clots could be observed nasally in the deep corneal stroma close to the Descemet's membrane. The intracorneal blood was washed out with balanced saline solution following deep corneal incision and lamellar dissection. Descemet's membrane was reattached with air injection into the anterior chamber. Two months later, visual acuity improved to 20/50, intraocular pressure was 16 mm Hg without medication and confocal microscopy showed deep stromal folds and limited endothelial cell loss. Viscoelastic entering the cornea at Schwalbe's line and reflux of blood from the collector channels to Schlemm's canal can account for corneal hematoma. Even six weeks after canaloplasty, successful blood removal could be fulfilled without rupturing the Descemet's membrane.
Purpose. Primary open-angle glaucoma (POAG), a chronic, degenerative optic neuropathy, requires persistent decrease of intraocular pressure so as to prevent visual impairment and blindness. However, long-term use of topical ocular medications may affect ocular surface health. Purpose of this study was to evaluate the influence of BAK-preserved prostaglandin analog treatment on the ocular surface health in patients with newly diagnosed POAG. Methods. 40 newly diagnosed POAG patients were included in this prospective study. Intraocular pressure (IOP), tear break-up time (TBUT), and ocular surface disease index (OSDI) were assessed at baseline and 3-month after starting treatment with BAK-preserved travoprost 0.004%. Results. IOP decreased in all
patients from baseline to 3-month final visit (23.80 ± 1.73mmHg versus 16.78 ± 1.27mmHg; P < 0.001). Mean TBUT decreased from11.70±1.86 seconds at baseline to 8.30 ± 1.29 seconds at 3-month final visit (<0.001).Mean OSDI score increased from31.63 ± 18.48 to 44.41 ± 16.48 (P < 0.001). Conclusions.This study showed that BAK-preserved travoprost 0.004%is an effective medication in newly diagnosed POAG patients, but its long-termusemay negatively influence ocular surface health by disrupting the tear film
stability. Further studies are needed to better understand the clinical effects of different preservative types and concentrations on the ocular surface
Traditional glaucoma surgery has been challenged by the advent of innovative techniques and new implants in the past few years. There is an increasing demand for safer glaucoma surgery offering patients a timely surgical solution in reducing intraocular pressure (IOP) and improving their quality of life.Thenewprocedures and devices aimto lower IOPwith a higher safety profile than fistulating surgery (trabeculectomy/drainage tubes) and are collectively termed “minimally invasive glaucoma surgery (MIGS).”The main advantage of MIGS is that they are nonpenetrating and/or bleb-independent procedures, thus avoiding the major complications of fistulating surgery related to blebs and hypotony. In this review, the clinical results of the latest techniques and devices are presented by their approach, ab interno (trabeculotomy, excimer laser trabeculotomy, trabecular microbypass, suprachoroidal shunt, and intracanalicular scaffold) and ab externo (canaloplasty, Stegmann Canal Expander, suprachoroidal Gold microshunt). The drawback of MIGS is that some of these procedures produce a limited IOP reduction compared to trabeculectomy. Currently, MIGS is performed in glaucoma patients with early to moderate disease and preferably in combination with cataract surgery.
PURPOSE: To report 5-year treatment outcomes in the Tube Versus Trabeculectomy (TVT) Study. DESIGN: Multicenter randomized clinical trial. METHODS: SETTINGS: Seventeen clinical centers. STUDY POPULATION: Patients 18 to 85 years of age who had
previous trabeculectomy and/or cataract extraction with intraocular lens implantation and uncontrolled glaucoma with intraocular pressure (IOP) >18 mm Hg and 21 mm Hg or not reduced by 20%, IOP <5 mm Hg, reoperation for glaucoma, or loss of light perception vision). RESULTS: A total of 212 eyes of 212 patients were enrolled, including 107 in the tube group and 105 in the trabeculectomy group. At 5 years, IOP (mean +/- SD) was 14.4+/- 6.9 mm Hg in the tube group and 12.6+/- 5.9 mm Hg in the trabeculectomy group (P = .12). The number of glaucoma medications (mean +/- SD) was 1.4 +/- 1.3 in the tube group and 1.2 +/- 1.5 in the trabeculectomy group (P = .23). The cumulative probability of failure during 5 years of follow-up was 29.8% in the tube group and 46.9% in the trabeculectomy group (P = .002; hazard ratio = 2.15; 95% confidence interval =1.30 to 3.56). The rate of reoperation for glaucoma was 9% in the tube group and 29% in the trabeculectomy group (P = .025). CONCLUSIONS: Tube shunt surgery had a higher success rate compared to trabeculectomy with MMC during 5 years of follow-up in the TVT Study. Both procedures were associated with similar IOP reduction and use of supplemental medical therapy at 5 years. Additional glaucoma surgery was needed more frequently after trabeculectomy with MMC than tube shunt placement.
Purpose—The purpose of this study was to visualize the aqueous outflow system in three dimensions (3D) in living human eyes, and to investigate the use of commercially available Spectral-domain optical coherence tomographic (SD-OCT) systems for this purpose. Design—This was a prospective observational study. Participants and/or Controls—One randomly determined eye in each of six normal healthy subjects was included. Testing—3D SD-OCT imaging of the aqueous humor outflow structures was performed with two devices: Cirrus HD OCT (Carl Zeiss Meditec, Inc., Dublin CA) and Bioptigen SDOIS (Bioptigen, Inc., Research Triangle, NC). Main Outcome Measures—3D virtual castings of Schlemm’s canal (SC) and more distal outflow structures created from scan data from each device . Results—Virtual casting of SC provided visualization of more aqueous vessels branching from SC than could be located by interrogating the 2D image stack. Similarly, virtual casting of distal structures allowed visualization of large and small aqueous outflow channel networks that could not be appreciated with the conventional 2D visualization. Conclusions—The outflow pathways from SC to the superficial vasculature can be identified and tracked in living human eyes using commercially available SD-OCT.
Purpose: Aim of the study was to assess the development of filtering blebs after canaloplasty. Methods: Twenty eyes of 20 consecutive patients receiving canaloplasty were included. All eyes were examined clinically (slit lamp), and by anterior segment optical coherence tomography and high-frequency ultrasound biomicroscopy to detect filtering blebs. Preoperative and postoperative intraocular pressure (IOP) and medications were recorded. No antimetabolites were used at any time. Two success criteria were defined to assess a possible correlation of bleb formation and success: (1) IOP </=21mm Hg and minimum 20% IOP reduction without medication and (2) IOP <18mm Hg without medication. Results: No filtering blebs were detected clinically. One patient had a filtering bleb-like structure as detected by anterior segment optical coherence tomography and ultrasound biomicroscopy. Mean IOP decreased significantly from 22.15±9.5mm Hg preoperatively to 13.3±9.9mm Hg at last follow-up (at 245±120.0 d). The number of medications was reduced significantly from 3.15±1.2 preoperatively to 0.55±0.94 postoperatively. Complete success rate was 65% for both success criteria.
Conclusions: Filtering blebs occur rarely after canaloplasty. In canaloplasty, IOP reduction seems to be independent of subconjunctival aqueous drainage, thus, avoiding the problems of conjunctival scarring
BACKGROUND: The aim of this study was to evaluate the intraocular pressure (IOP)-lowering effect of cataract surgery combined with canaloplasty compared to canaloplasty alone. METHODS: A total of 43 patients underwent canaloplasty without cataract surgery (group K) and 20 patients underwent canaloplasty with cataract surgery (group K+P). The IOP-lowering effect was measured 4-6 weeks, 3, 6 and 12 months postoperatively.
RESULTS: The mean presurgical IOP was 18.26 ± 6.07 mmHg in group K and 16.95 ± 3.46 mmHg in group K+P. In group K the mean IOP was 13.08 ± 5.67 mmHg (28% reduction) 4-6 weeks postoperatively, 13.25 ± 4.51 mmHg (27%) 3 months postoperatively, 12.4 ± 3.25 mmHg (32%) 6 months postoperatively and 12.5 ± 2.45 mmHg (32%) 12 months postoperatively. The mean IOP in group K+P was 11.41 ± 4.87 mmHg (33%) 4-6 weeks postoperatively, 10.4 ± 4.88 mmHg (39%) 3 months postoperatively, 11.0 ± 2.89 mmHg (35%) 6 months postoperatively and 13.0 ± 1.94 mmHg (23%) 12 months postoperatively (no statistical significant difference between the two groups).
CONCLUSIONS: Combined cataract-canaloplasty surgery has no significant additional IOP-lowering effect compared to canaloplasty alone.
Purpose: To report the surgical outcome of canaloplasty for primary open angle glaucoma (POAG) in Caucasian patients during a 2-year follow-up period. Methods: Caucasian patients consecutively treated by canaloplasty with 360 degree catheterization of Schlemm’s canal for medically uncontrolled POAG between January 2008 and January 2009 at the Department of Ophthalmology, Radboud University Nijmegen Medical Centre, were included in this retrospective, non-comparative case series. All surgery was performed by one of two highly trained glaucoma surgeons. Patients were followed for 2 years postoperatively. Changes in intraocular pressure (IOP), visual acuity (VA), postoperative medications, and complications within the study period were recorded. Failure was based on IOP above 18 mmHg or below 5 mmHg or by the need for re-operation. Results: We included 53 eyes (26 right, 27 left) of 50 Caucasians with POAG, mean age 67.4 ± 8.8 years. 15 and 38 eyes were operated on by surgeon 1 and 2, respectively. VA remained stable in 73.6% and increased or decreased for more than 2 lines in 13.2% of cases. At baseline, all study eyes had a mean IOP of 26.7 ± 6.6 mmHg with 3.0 ± 1.1 glaucoma medications on average. Mean IOP decreased to 14.8 mmHg and 15.0 mmHg with 0.7 and 0.8 medications at mean after 1 and 2 years, respectively. Mean IOP after 2 years was 15.6 ± 3.0 mmHg and 13.5 ± 1.5 mmHg in phakic and pseudophakic eyes, respectively. Visual acuity remained Absolute success after 1 and 2 years was 73.6% and 72.7%, respectively. Complete success rates after 1 and 2 years were 92.5% and 90.9%, respectively. There were no cases of severe visual loss, hypotony or other devastating complications during the follow-up period. Reoperation for IOP regulation was necessary in two cases. Conclusion: Canaloplasty achieved a significant reduction of IOP and of antiglaucomatous medication in Caucasian patients with POAG at 24 months postoperatively with a high success rate and an excellent safety profile.
Purpose: To compare the safety and efficacy of canaloplasty with viscocanalostomy when performed in both eyes of patients with bilateral open-angle glaucoma. Patients and Methods: This comparative case series investigated 30 eyes of 15 adult patients with bilateral primary open-angle glaucoma who had canaloplasty performed in one eye and viscocanalostomy performed in the contralateral eye. Qualifying preoperative intraocular pressures (IOP) were at least 18mm Hg with historical IOPs of at least 21mm Hg. In canaloplasty, a microcatheter was used to viscodilate the full circumference of Schlemm canal in conjunction with the placement of a trabecular meshwork tensioning suture. Primary outcome measures included IOP, glaucoma medication usage, and adverse events. Results: With a follow-up period of 18 months, both the canaloplasty and viscocanalostomy groups showed statistically significant reductions in mean IOP (P<0.01) and number of supplemental medications (P<0.01) as compared with preoperative values. In the canaloplasty cohort, eyes had a mean IOP of 14.5±2.6mm Hg on 0.3±0.5 medications at 18 months postoperatively as compared with preoperative levels of 26.5±2.7mm Hg on 2.1±1.0 medications. In the viscocanalostomy cohort, eyes had a mean IOP of 16.1±3.9mm Hg on 0.4±0.5 medications at 18 months as compared with preoperative levels of 24.3±2.8mm Hg on 1.9±0.8 medications (P=0.02). No patient in either cohort experienced significant complications. Conclusions: Canaloplasty and viscocanalostomy were safe and effective in the surgical management of open-angle glaucoma. Canaloplasty procedures showed superior efficacy to viscocanalostomy in the reduction of IOP (P=0.02) and both procedures demonstrated excellent safety profiles.
Ab externo Schlemm’s canal (SC) surgery (e.g. viscocanalostomy and canaloplasty) is a valuable alternative to glaucoma filtration surgery. It targets the abnormally high resistance to outflow in the trabecular meshwork and reestablishes the physiologic outflow system. In viscocanalostomy, viscoelastic substance is injected to dilate SC which in turn leads to microdisruptions of the inner wall. In canaloplasty, the additional intracanalicular suture stent keeps the canal patent and enhances the circumferential flow. A prerequisite for these procedures to work is the integrity of the distal outflow system, which can be evaluated by two clinical tests before surgery: provocative gonioscopy with blood reflux and fluorescein channelography. Ab externo SC surgery is suitable for open-angle glaucoma, but also for angle closure glaucoma in combination with cataract extraction. IOP reduction to the mid-teens for viscocanalostomy, and to the lower teens for canaloplasty can be expected. The majority of complications seen in filtering surgery are largely eliminated by the nonpenetrating and bleb-independent approach. Postoperative care is minimal as no bleb management like needling is required, and hypotony-related complications are largely avoided by the intrinsic resistance of the physiologic outflow system. For its efficacy and high safety profile, ab externo SC surgery will continue to play an increasing role and will change the current concept of glaucoma surgery towardsearlier intervention. Surgeons will be well advised to implement these antimetabolite-free procedures into their armamentarium to meet the expectations of the demanding glaucoma patient.
Discussion: Previous published reports have demonstrated the effects of canaloplasty and phacocanaloplasty through 12, 24, and 36 months post-op [1-4]. In this study, both canaloplasty and trabeculectomy alone were effective in reducing IOP in adult patients with open-angle glaucoma with IOP outcomes favoring trabeculectomy (p=0.005). However, in this series, eyes undergoing canaloplasty had a more favorable safety profile, visual acuity outcome, and required significantly fewer postoperative interventions. As with any retrospective comparison, one obvious issue is the introduction of selection bias influencing the results. Lower IOP targets and more severe disease are well understood reasons to select a standard trabeculectomy over any less invasive procedure, including canaloplasty. Besides number of medications and the IOP at baseline, severity of disease was not measured in this study. Patients with more severe disease may have been more likely to be selected for trabeculectomy and comparative IOP results may be affected by this possible selection bias. The results on average of an endpoint IOP 2 mmHg higher in the canaloplasty cohort with the same number of topical medications is a reasonable expectation compared with other trial data comparing trabeculectomy and canaloplasty. Conclusion: Canaloplasty safely and effectively lowers IOP without intentional bleb formation, requires less postoperative management than trabeculectomy, and has fewer postoperative complications
Purpose: To determine the safety and efficacy of circumferential trabeculotomy for congenital glaucomas using an illuminated microcatheter. Methods: This was a retrospective chart study involving 11 eyes from 7 patients with primary or secondary congenital or juvenile glaucoma who underwent circumferential trabeculotomy performed with an illuminated microcatheter over a 2-year period. Data from eyes with 6 or more months of follow-up intraocularpressure (IOP) data were included in the analysis. Mean IOP was determined along with a survival analysis. Unqualified success was defined as an IOP<21mm Hg and at least a 30% reduction in IOP without the use of IOP-lowering agents and a qualified success when medications were needed to reach this goal. Results: Mean IOP (mm Hg) was reduced from 33.8±6.3 preoperatively to 18.3±3.5 at the final postoperative visit
(P-value<0.001). Length of follow-up was 8 to 12 months (mean of 11 mo). A qualified success was seen in 90.1% of eyes and an
unqualified success in 81.8%. If eyes with previous angle surgery were excluded, the unqualified success was 87.5% and the qualified success was 100%. Transient hyphema was seen in all cases. No long-term surgical complications were seen. Conclusions: Circumferential trabeculotomy performed with an illuminated microcatheter provided significant IOP lowering in all
patients with unqualified success in the majority of eyes and no significant complications. Further study with even longer follow-up
Elevated IOP in clinical practice is usually seen in glaucoma or ocular hypertension. Glaucoma affects 60 million people worldwide and 8.4 million are bilaterally blind from this chronic disease.1 Options for reducing IOP rely on pharmacological agents, laser treatments and surgery which may be penetrating or non-penetrating. The last twenty years has seen significant changes in all of these strategies. This review aims to cover these clinical options and introduce some of the new technologies currently in development for the clinical lowering of IOP.
Canaloplasty is a recent non penetrating glaucoma surgical procedure where Schlemm's canal is dilated and trabecular meshwork distended by tensioning polypropylene suture. The aim of this study was to visualize the iridocorneal angle after the canaloplasty procedure by means of two different ultrasound biomicroscopy (UBM) units. Ten eyes of nine patients with primary open angle glaucoma (average age 62 years) underwent canaloplasty (six eyes) or canaloplasty combined with phacoemulsification and in-the-bag intraocular lens implantation (4 eyes). Both 50 MHz (Paradigm P45) and 80 MHz (i-UltraSound) systems were used. All procedures were performed by the same surgeon. UBM examination was performed 3 to 12 (mean 7 +/- 3.1) months after surgery. No, mild and good trabecular meshwork distension by suture tensioning was graded as 0, 1 and 2 according to the higher resolution 80 MHz images. Both ultrasound systems could show intrascleral lake and trabecular meshwork distension, which was graded as 0, 1 and 2 in 10%, 30% and 60% of eyes, respectively. Schlemm's canal could be imaged with the 80 MHz transducer only. The overall qualified success of canaloplasty (80%) was apparently correlated with suture tensioning (r=0.64). In our experience, after canaloplasty the 80 MHz but also 50 MHz technology can show trabecular meshwork distension. A greater number of eyes are needed to assess the correlation between intraocular pressure decrease and suture tensioning.
Canaloplasty appears to be associated with a lower impairment of QoL after surgery and to be a surgical method with a higher patient satisfaction rate, when compared to TET. However we need to await long term results from the surgical effect on the
lowering of the intraocular pressure in orderto confirm long-term patient satisfaction with this new type of surgery.
Purpose: To report the incidence and management of Descemet membrane detachment (DMD) after canaloplasty.
Methods: Review of all patients who developed DMD aftercanaloplasty at Tulane Glaucoma Services was performed. Visual acuity, intraocular pressure, and number of glaucoma medications up to 1 year of follow-up were included in the analysis.
Results: The incidence of DMD was 7.4% (12 eyes of 162). Eightythree percent (10/12) of the DMDs involved the inferior quadrants and measured <3mm. Intracorneal hemorrhage within DMD occurred in 58% (7/12), whereas 42% (5/12) developed DMD with intracorneal viscoelastic (Healon GV) alone. Two patients had large detachments measuring 5 to 6mm extending into the visual axis. DMD resolved completely with or without drainage except
for 1 patient who developed corneal decompensation, needing penetrating keratoplasty.
Conclusions: DMD with or without intracorneal hemorrhage is not an infrequent complication of canaloplasty and can occasionally lead to corneal decompensation.
Purpose of review: Over the past several years, numerous clinical trials in glaucoma have contributed to our understanding of the medical and surgical treatment of the disease. The goal of this review is to summarize the findings and conclusions of what the authors feel are the key clinical trials in glaucoma. Recent findings: One of the major findings of Low-Pressure Glaucoma Treatment study was that patients randomized to the brimonidine group were statistically less likely to have progressive visual field loss than those randomized to the timolol group, even though there was no significant difference between the intraocular pressure (IOP)-lowering effect of these two drugs. The Ocular Hypertension Treatment Study has effectively demonstrated that patients with ocular hypertension should be risk stratified prior to initiation of treatment and that it appears to be relatively safe to delay treatment in low-risk patients. The 3-year canaloplasty study demonstrates the long-term safety and efficacy of this surgery. However, it also demonstrates that canaloplasty can deliver a modest IOP reduction and therefore is likely more suited for patients with mild damage and a higher target IOP. The 1-year results from the Ahmed Baerveldt Comparison Study do not demonstrate a clear superiority of one implant over the other. These findings are consistent with prior retrospective studies in the literature.
Summary: These four studies have furthered our understanding of the field of glaucoma and provided key insights into the medical and surgical management of patients with this complex disease.
Purpose: To report the observation of a perilimbal and/or episcleral vessel fluid wave seen during trabectome surgery, newly termed episcleral venous fluid wave. Patients and Methods: In 4 consecutive patients undergoing phacotrabectome
surgery, the authors observed the nasal perilimbal and episcleral collector vessels for an anticipated wave of fluid adjacent
to the trabeculotomy site. The wave of fluid was elicited during the irrigation and aspiration phase of cataract surgery at the time of low intraocular pressure with no infusion (foot pedal position 0) to maximum irrigation (foot pedal position 2), creating a maximal
pressure gradient for balanced salt solution (BSS) to surge into the anterior chamber and potentially out of the newly cleaved canal
venous collector system Results: During the anterior chamber surge of BSS, the authors observed in 4 cases, 2 types of fluid waves, one episcleral and sectorial in distribution and the other through the perilimbal conjunctival vessels. There was a correlation between the location of retrograde reflux of blood into the anterior chamber during the low-pressure phase and a wave of BSS into the immediate adjacent collector.
Conclusions: The authors believe the fluid wave signifies intraoperative structural patency of the conventional outflow system
from the anterior chamber to the episcleral and conjunctival distal collectors. The fluid wave is a sign that the collector system is at
least anatomically functional, however, not necessarily physiologically functional. The presence or absence of a fluid wave may
better explain canal-based surgical outcomes and could be a prognostic indicator for success after a trabectome surgery.
Purpose: This review article addresses the different aspects that influence the choice and sequence of surgical treatment in patients with coexisting openangle glaucoma and cataract. The effect of phacoemulsification on the intraocular pressure (IOP) and on a preexisting bleb is discussed and phacotrabeculectomy and trabeculectomy are compared.
Moreover, the most recent surgical pressure lowering techniques in combination with phacoemulsification are reviewed: iStent, Trabectome, Hydrus, Cypass and Canaloplasty.
Methods: Medline database was used to search for relevant, recent articles.
Conclusion: A sustained IOP decrease of 1.5 mmHg can be expected after a phacoemulsification in patients with open-angle glaucoma. The higher the preoperative pressure, the greater the IOP lowering will be. A phacoemulsification on a trabeculectomized eye will often lead to reduced bleb function and an IOP rise of on average 2 mmHg after 12 months. Compared to a trabeculectomy, phaco-trabeculectomy will have a less IOP lowering effect and a higher complication rate. iStent and Trabectome combined with phacoemulsification can decrease the IOP with 3 to 5mmHg, with a low complication rate. The combination of Cypass and Hydrus with phaco-surgery may have a more significant IOP lowering effect but long term results are not yet published. Combining Canaloplasty with phacoemulsification is a more challenging surgery but if a tension suture can be placed, an IOP decrease around 10 mmHg might be expected.
PURPOSE To compare circumferential trabeculotomy performed with an illuminated microcatheter with standard goniotomy for the treatment of congenital glaucoma. METHODS The short-term results of catheter-assisted trabeculotomy with an illuminated microcatheter were retrospectively compared with those of goniotomy in patients treated for congenital glaucoma. Success with either approach was defined as an intraocular pressure (IOP) \21 mm Hg with at least a 30% reduction from preoperative pressure levels at 12-month follow-up. Complete success was defined when the target IOP levels were reached without the use of antiglaucoma medication, and qualified success was defined when antiglaucoma drops were required to meet this level of IOP. RESULTS A total of 24 eyes of 20 patients were included. Microcatheter-assisted circumferential trabeculotomy demonstrated a 91.6% qualified and 83.3% unqualified success rate with 12-month follow-up that exceeded the 53.8% qualified and 46.2% unqualified success rate of conventional goniotomy. CONCLUSIONS In congenital glaucoma, during the first year after surgery, trabeculotomy performed with an illuminated microcatheter appears to be more effective than ab interno goniotomy.
No complications were seen in either group; however, the follow-up was relatively short.
Purpose. This is a case report of intracorneal hematoma after canaloplasty and clear cornea phacoemulsification Methods. A 75-year-old woman presented with primary open angle glaucoma and visually significant cataract. Canaloplasty and clear corneal phacoemulsification were performed. Postoperatively she had an intracorneal hematoma, which was removed through a clear corneal tunnel. Results. Preoperative best-corrected visual acuity (BCVA) was 20/40 in the right eye and mean intraocular pressure (IOP) was 20 mmHg. Uneventful canaloplasty, clear corneal phacoemulsification, and implantation of a posterior chamber intraocular lens were performed. One day after the operation, BCVA was 20/400 in the right eye. The IOP was 8 mmHg. Anterior segment examination revealed a nasally located intrastromal hematoma between corneal stroma and Descemet membrane. The intracorneal hematoma was removed through a clear corneal tunnel. Six months postoperatively, BCVA was 20/25 in the right eye. The IOP with one medication was 17 mmHg. Conclusions. This operation was a minimally invasive technique to remove intrastromal hematocornea after viscocanaloplasty
Aim To assess the epithelial features of the bulbar conjunctiva using in vivo confocal microscopy in patients with glaucoma undergoing canaloplasty.
Methods Thirty consecutive patients with glaucoma were enrolled. Canaloplasty was considered successful if the preoperative intraocular pressure (IOP) was reduced by one-third. The conjunctiva was examined using confocal laser-scanning microscopy 1 week before (baseline) and 12 weeks after surgery. The mean density (MMD, cysts/mm2) and mean area (MMA, mm2) of conjunctival microcysts and IOP were measured. Anterior segment optical coherence tomography was performed to evaluate post-operative trabecular distension and scleral modifications at the surgery site. Results Twelve weeks after surgery, canaloplasty was successful in 23 patients (group 1) but unsuccessful in 7 (group 2). At baseline, IOP was 28.162.98 and 28.362.81 mm Hg, MMD was 10.6164.31 and 11.3565.6 and MMA was 2845.026411.85 and 2700.566518.85 in groups 1 and 2, respectively (p>0.05). Twelve weeks after canaloplasty, mean IOP was 13.264.48 (p<0.05) and 24.663.48 mm Hg in groups 1 and 2, respectively. In group 1, MMD and MMA were 37.86621.4 and 11997.8468630.35, respectively, a fourfold increase compared to baseline (p<0.001); no significant differences were found in group 2. Conjunctival bleb was not documented in any case.
Conclusions Conjunctival microcysts were evident in all glaucomatous eyes prior to surgery, and tended to increase in density and surface area after successful canaloplasty. These findings indicated enhanced aqueous humour filtration across the sclera and conjunctiva after canaloplasty.
Purpose: Long-term antiglaucomatous drug administration may cause irritation, dry eye, allergy, subconjunctival fibrosis, or increased risk of glaucoma surgery failure, potentially due to the preservative benzalkonium chloride (BAK), whose toxic, proinflammatory, and detergent effects have extensively been shown experimentally. We hypothesize that BAK also influences trabecular meshwork (TM) degeneration.
Methods: Trabecular specimens were examined using immunohistology and reverse transcriptase–polymerase chain reaction. A trabecular cell line was stimulated by BAK and examined for apoptosis, oxidative stress, fractalkine and SDF-1 expression, and modulation of their receptors. An experimental model was developed with BAK subconjunctival injections to induce TM degeneration. Mass spectrometry (MS) imaging assessed BAK penetration after repeated instillations in rabbit eyes.
Results: Trabecular specimens showed extremely low densities of trabecular cells and presence of cells expressing fractalkine and fractalkine receptor and their respective mRNAs. Benzalkonium in vitro induced apoptosis, oxidative stress, and fractalkine expression and inhibited the protective chemokine SDF-1 and Bcl2, also inducing a sustained intraocular pressure (IOP) increase, with dramatic apoptosis of trabecular cells and reduction of aqueous outflow. MS imaging showed that BAK could access the TM at measurable levels after repeated instillations.
Conclusion: BAK enhances all characteristics of TM degeneration typical of glaucoma—trabecular apoptosis, oxidative stress, induction of inflammatory chemokines—and causes degeneration in acute experimental conditions, potentially mimicking long-term accumulation. BAK was also shown to access the TM after repeated instillations. These findings support the hypothesis that antiglaucoma medications, through toxicity of their preservative, may cause further long-term trabecular degeneration and therefore enhance outflow resistance, reducing the impact of IOP-lowering agents.
Purpose—To evaluate the outcomes of 360-degree suture trabeculotomy in childhood glaucoma with poor prognosis. Subjects and Methods—A nonrandomized, retrospective chart review was performed on pediatric patients (under 18 years old) treated with a 360-degree suture trabeculotomy for glaucoma. The cases were categorized into the following groups: (1) primary congenital glaucoma with birth-onset presentation accompanied by corneal clouding noted at birth, (2) primary congenital glaucoma with onset or presentation after 1 year of age, (3) primary congenital glaucoma with prior failed goniotomy surgery, (4) infantile-onset glaucoma following congenital cataract surgery, and (5) infantile-onset glaucoma with associated ocular/systemic anomalies. Results—A total of 45 eyes of 33 patients were analyzed. The mean preoperative intraocular pressure (IOP) was 34.3 ± 6.7 mm Hg on an average of 1.5 medications. Median age at time of surgery was 7 months. Mean final IOP (median last follow-up or failure, 12 months) was 22.2 ± 7.1 mm Hg on an average of 1.5 medications. The probability of success according to time after surgery was 87% at 6 months, 63% at 1 year, and 58% at 2 years. Kaplan-Meier analysis of Groups 1-4 versus Group 5 failed to demonstrate a statistically significant difference (p = 0.13). Of 5 eyes with port wine mark–related glaucoma, 2 had a large (>50%), persistent postoperative hyphema and concurrent vitreous hemorrhage. Conclusions—Children with a wide range of ocular pathologies can be successfully treated with 360-degree suture trabeculotomy. Further evaluation of this surgical technique in primary congenital glaucoma and open-angle glaucoma following congenital cataract surgery is warranted.
Canaloplasty is a method of lowering intraocular pressure (IOP) by which a flexible, beacon tipped microcatheter equipped with an ophthalmic viscosurgical device (OVD) delivery system is used to catheterize and introduce a suture into Schlemm’s canal. Ligation of this suture provides tension on the canal and facilitates aqueous outflow. Canaloplasty is designed to be a blebless procedure that requires no antifibrotic agents and has been shown to safely and effectively lower IOP in patients with open-angle glaucoma (OAG) with minimal complications. Most importantly, no blebrelated adverse events are associated with this procedure. When contemplating surgical management of OAG, canaloplasty may be considered.
Background: To report 3-year results investigating the safety and efficacy of canaloplasty, a procedure involving circumferential viscodilation of Schlemm’s canal and tensioning of the inner canal wall to treat open-angle glaucoma.
Methods: This was a prospective, multi-center, interventional study of 109 eyes of 109 adult, open-angle glaucoma patients undergoing canaloplasty or combined cataract-canaloplasty surgery. Qualifying preoperative intraocular pressures (IOP) were at least 16 mmHg with historical IOPs of at least 21 mmHg with or without medical therapy. A flexible microcatheter was used to viscodilate the full circumference of the canal and to place a trabecular tensioning suture. Primary outcome measures included IOP, glaucoma medication usage, and adverse events. Results Eyes with canaloplasty showed a mean baseline IOP of 23.0 ± 4.3 mmHg and mean glaucoma medication usage of 1.9±0.7 medications, which decreased to a mean IOP of 15.1±3.1 mmHg on 0.9±0.9 medications at 3 years postoperatively. Eyes with combined cataract-canaloplasty surgery showed a mean baseline IOP of 24.3±6.0 mmHg on 1.5±1.2 medications, which decreased to a mean IOP of 13.8±3.2 mmHg on 0.5±0.7 medications at 3 years. Intraocular pressure and medication use results for all study eyes were significantly decreased from baseline (p <0.00001) at all intervals. Late postoperative complications included cataracts (19.1%) and transient IOP elevation (1.8%). Conclusions: Canaloplasty demonstrated significant and sustained IOP reductions accompanied by an excellent short- and long-term safety profile in adult patients with open-angle glaucoma.
Purpose: To review the prevalence, diagnosis, causes, and treatment of ocular surface disease (OSD) in patients with ocular hypertension or primary open-angle glaucoma.
Methods: A review of the literature pertaining to OSD and glaucoma.
Results: Recent studies indicate that OSD demonstrates an overall prevalence in glaucoma of 42% (range 20–59%) and is severe in 36% (range 14–66%). Further, the prevalence appears to increase with the greater the number of glaucoma drugs prescribed. Symptoms and signs are non-specific to the anterior surface of the eye and are thought to result from allergic, toxic, or pro-inflammatory conditions. However, the specific causes remain incompletely described, but may result from the benzalkonium chloride (BAK) preservative or occasionally the ocular hypotensive active molecule itself. Additionally, anterior segment ocular diseases might be causative, such as allergy, blepharitis, dry eye, and eyelid anatomical abnormalities. Treatment may consist of using preservative-free or non-BAK preserved glaucoma medications. Also, although unproven specifically in glaucoma patients, treatment of associated diseases of the anterior surface might reduce signs and symptoms. Conclusions: OSD is common in treated glaucoma patients causing symptoms and signs that may impact on a patient’s quality of life. Treatment is directed towards any underlying disease process and the use of preservative-free or non-BAK-preserved glaucoma preparations.
BACKGROUND: Canaloplasty provides a new option in non-penetrating glaucoma surgery. The aim of this study is to examine its early postsurgical safety and efficacy.
PATIENTS AND METHODS: This was a retrospective study of canaloplasties performed at our institution in 2009 (n=46, 13 of which were combined with cataract surgery). The mean follow-up was 6.0±3.4 months. The most important parameters examined were intraocular pressure (IOP), number of topical medications, postoperative complications, and required additional surgery.
RESULTS: Mean presurgical IOP: 18.2±5.8 mmHg on a mean of 2.3±1.2 applied topical medications. Mean postsurgical IOP: 12.3±5.1 mmHg at 3 months, 11.7±3.0 mmHg at 6 months, and 12.6±2.4 mmHg at 12 months. Number of postsurgical medications: 0.8±1.1 at 3 months, 1.2±1.3 at 6 months, and 1.0±1.1 at 12 months. The most frequent postoperative complications were transient hypotension (32.6%), bleb leakage (26.1%), and microhyphema (23.9%). Revision surgery was required in 8.7% of all patients.
CONCLUSIONS: Canaloplasty showed a good IOP-reducing effect. Complications occurred mostly temporarily and were of a controllable nature.
Surgical intervention is mandatory in the case of documentation of the progression of glaucomatous optic neuropathy despite the administration of maximal tolerated medical therapy, and in cases where compliance is poor. Minimal complications, good long-term intraocular pressure (IOP) control, and precisely titrated target IOPs resulting in avoidance of visual impairment are the primary goals of surgical intervention. This article is an attempt to provide a broad overview of the therapeutic options available to the glaucoma surgeon. The available surgical modalities have undergone modifications and refinements
over time, with a view to improve patient outcomes and visual recovery, yet are fraught with intra- and postoperative complications. The risk and benefits of each of the available surgical options must be critically evaluated and customized to fit the needs of the particular patient. There is insufficient evidence at present to establish the superiority of any of these surgeries over the other.
Purpose: To report a case of an intracorneal hematoma after canaloplasty. Methods: Interventional case report of a surgical method used to resolve an intracorneal hematoma complication after canaloplasty. Results: A 45-year-old man with uncontrolled pigmentary openangle glaucoma underwent canaloplasty for glaucoma in the left eye. The patient previously underwent radial keratotomy for myopia in the same eye in 1997. Visual acuity was 20/20 without corrective lenses; intraocular pressure was 25 mm Hg with maximal medical therapy. During the surgical procedure, the canaloplasty microcatheter encountered an obstacle at the 6-o’clock position. During catheterization, a high-weight viscoelastic substance is normally injected in the canal. This probably caused a limited detachment of the Descemet membrane. On the day after surgery, slit-lamp biomicroscopy showed a large intracorneal hematoma that threatened the visual axis. A partial-thickness paracentesis was then performed on day 2 to remove the hematoma. Conclusions: Intracorneal hematoma is a rare complication of canaloplasty for glaucoma. The blood can be removed without interrupting the Descemet membrane by partial-thickness paracentesis.
This case report presents canaloplasty as a bleb-free surgical option for lowering intraocular pressure in cases with postoperative conjunctival scarring
PURPOSE: To report 3-year results of the safety and efficacy of canaloplasty, a procedure involving circumferential viscodilation and tensioning of the inner wall of Schlemm canal to treat open-angle glaucoma.
SETTING: Multicenter surgical sites. DESIGN: Nonrandomized multicenter clinical trial.
METHODS:This study comprised adult open-angle glaucoma patients having canaloplasty or combined cataract-canaloplasty surgery. Qualifying preoperative intraocular pressures (IOPs) were at least 16 mm Hg with historical IOPs of at least 21 mm Hg. A flexible microcatheter was used to viscodilate the full circumference of the canal and to place a trabecular tensioning suture. Primary outcome measures included IOP, glaucoma medication use, and adverse events.
RESULTS:Three years postoperatively, all study eyes (n = 157) had a mean IOP of 15.2 mm Hg ± 3.5 (SD) and mean glaucoma medication use of 0.8 ± 0.9 compared with a baseline IOP of 23.8 ± 5.0 mm Hg on 1.8 ± 0.9 medications. Eyes with combined cataract-canaloplasty surgery had a mean IOP of 13.6 ± 3.6 mm Hg on 0.3 ± 0.5 medications compared with a baseline IOP of 23.5 ± 5.2 mm Hg on 1.5 ± 1.0 medications. Intraocular pressure and medication use results in all eyes were significantly decreased from baseline at every time point (P<.001). Late postoperative complications included cataract (12.7%), transient IOP elevation (6.4%), and partial suture extrusion through the trabecular meshwork (0.6%).
CONCLUSION:Canaloplasty led to a significant and sustained IOP reduction in adult patients with open-angle glaucoma and had an excellent short- and long-term postoperative safety profile.
Purpose: To assess the safety and efficacy of canaloplasty (360-degree viscodilation and tensioning of the Schlemm canal) in Whites with open-angle glaucoma (OAG).
Methods: In a prospective study, 32 consecutive patients with medically uncontrolled OAG underwent primary canaloplasty with a follow-up time of more than 1 year. Laser goniopuncture was performed if postoperative intraocular pressure (IOP) was above 16 mmHg. IOP, number of antiglaucomatous medications, bestcorrected visual acuity, and intraoperative and postoperative complications were recorded. Complete success was defined as an IOP r21, 18, and 16mm Hg without medications, and qualified success with or without medications, respectively. Results: The mean IOP dropped from 27.3±5.6mm Hg preoperatively to 12.8±1.5mm Hg at 12 months and 13.1±1.2mm Hg at
18 months (P<0.001). The complete success rate of an IOP r21, 18, and 16mm Hg was 93.8% [95% confidence interval (CI) 0.86- 1.0], 84.4% (95% CI 0.73-0.98), and 74.9% (95% CI 0.61-0.92), respectively, at 12 months. Laser goniopuncture was performed on 6 eyes (18.1%) 3.3±2.1 months postoperatively. The mean IOP was 20.6±4.2mm Hg before and 14.2±2.2mm Hg after goniopuncture. The number of medications dropped from 2.7±0.5 before surgery to 0.1±0.3 after surgery (P<0.001). The postoperative best-corrected visual acuity at last visit (0.38±0.45; range: 0 to 1.8) was comparable with that of preoperative values (0.36±SD 0.37; range: 0 to 1.6) (P=0.42). In all but 1 eye, canaloplasty was completed. Minor intraoperative or postoperative complications like Descemet membrane detachment in 2 eyes, elevated IOP in 1 eye, and suprachoroidal passage of the catheter in 4 eyes were encountered. In 1 eye, circumferential cannulation of the Schlemm canal was impossible.
Conclusions: Canaloplasty seems to be a promising and effective surgical procedure in Whites with OAG. Postoperative IOP levels are in the low-to-mid-teens. The procedure can be regarded as safe, but has its own profile of complications
Purpose: To compare operative outcomes of patients after canaloplasty and trabeculectomy through 12 months’ follow-up.
Design: Retrospective, nonrandomized, comparative case series.
Participants: We included 33 eyes of 33 patients who underwent canaloplasty and 46 eyes of 46 patients who underwent trabeculectomy with 12 months’ of postoperative follow-up.
Methods: Patients with open-angle glaucoma who underwent either canaloplasty or trabeculectomy with mitomycin C to control the intraocular pressure (IOP) between January 2007 and December 2008 were included. All surgeries were performed by a single surgeon (R.S.A.).
Main Outcome Measures: Change in IOP, visual acuity (VA), postoperative medications, failure based on IOP ( 18 or 4 mmHg at 1 year) or second operative procedure (any eye requiring reoperation) and complication rates at 12 months.
Results: There were no differences in demographics, previous surgery, or preoperative and postoperative VA between the groups. The mean percentage reduction in IOP from preoperative values at 12 months after surgery was 32% ( 22%) for the canaloplasty group compared with 43% ( 28%) for the trabeculectomy group (P =0.072, Student t test). The median reduction in the number of medications at 12 months’ follow-up was 3
in the trabeculectomy group and 2 in the canaloplasty group (P =0.064). A higher percentage of patients treated with canaloplasty than trabeculectomy (36% vs. 20%) required postoperative medications, although this did not attain significance (P =0.12). Failure based on IOP (IOP >18 or >4 mmHg at 12 months) was 12.1% (4/33
patients) for the canaloplasty group and 4.3% (2/46 patients) for the trabeculectomy group (P = 0.23, Fisher exact test). There was no difference in surgical failure rates between the canaloplasty (n =5; 15%) and trabeculectomy (n =5; 11%) groups (P =0.74).
Conclusions: Canaloplasty and trabeculectomy both achieved significant reduction in IOP at 12 months.
Purpose: To report surgical results of canaloplasty surgery for primary open-angle glaucoma (POAG) in Japanese patients.
Methods: Eleven eyes of 9 POAG patients underwent canaloplasty surgery at Toyama University Hospital. Three eyes of 3 patients underwent canaloplasty alone and 8 eyes of 6 patients underwent canaloplasty combined with cataract surgery. Canaloplasty was performed with a 10-0 polypropylene tensioning suture and an iTrackTM 250A microcatheter. All patients were followed up for 12 months. Changes in intraocular pressure (IOP) and postoperative complications were examined. Results: Mean preoperative IOP was 23.4 ± 5.5 mm Hg. Mean number of antiglaucoma drops was 2.8 ± 0.6 before canaloplasty and decreased to 1.2 ± 0.8 at 12 months after canaloplasty (p < 0.01). Mean IOP decreased postoperatively, being 13.7 ± 2.8 mm Hg at 1 month, 12.8 ± 3.5 mm Hg at 3 months, 14.0 ± 4.4 mm Hg at 6 months, and 15.0 ± 4.1mm Hg at 12 months. The most frequent postoperative complication was mild hyphema (45.5%), which disappeared within 14 days after surgery.
Conclusions: Canaloplasty may be an alternative surgery for POAG patients to reduce IOP to a value of approximately 15mm Hg.
The aim of glaucoma surgery is to lower the intraocular pressure in order to reduce the risk of further glaucomatous progression, particularly in cases refractory to topical therapy. Although effective in reducing intraocular pressure, these procedures are not without complications, with endophthalmitis being one of the most serious. A PubMed review of the literature wasperformed for trabeculectomy, glaucoma drainage device procedures (Ahmed, Baerveldt and Molteno implants) and non-penetrating glaucoma surgery (deepsclerectomy and viscocanalostomy) for reports of postoperative infection, including blebitis and endophthalmitis. The literature on infections relating to non-penetrating glaucoma surgery is sparse compared with penetrating surgery, but this may be a reflection of the relatively shorter follow-up duration and comparatively smaller body of data available on nonpenetrating procedures. Overall, there is not enough evidence, in terms of well-constructed randomised clinical trials with sufficiently large sample sizes and long follow-up durations, to be able to make informed comparisons of the risk of postoperative endophthalmitis and infection between the various glaucoma operations. This review article summarises the incidences of endophthalmitis from the literature and discusses the major risk factors for postoperative infection.
OBJECTIVE: An attempt has been made to evaluate transient anterior chamber haemorrhage after canaloplasty. METHOD: In the period from November 2008 to October 2009 a total of 21 eyes in 17 patients underwent canaloplasty for primary open angle glaucoma in our clinic. At the end of surgery all eyes left the surgical table with an intraocular pressure (IOP) of 5 - 10 mmHg and a deep anterior chamber without any bleeding.
RESULTS: The IOP on day 1 after surgery was 9.6 mmHg in average. By that time 15 of 21 eyes showed anterior chamber haemorrhage with a hyphaema between 0.5 - 2 mm in height. Eyes without hyphaema showed an IOP of > 15 mmHg at the same time. In no case was there further haemorrhage, the blood was absorbed in all cases within a maximum of 1 week without further complications.
CONCLUSION: In contrast to trabeculectomy, where the natural anterior chamber water outflow is by-passed via an artificial fistula, canaloplasty attempts to re-establish the physiological anterior chamber water draining system by means of a 360 degree viscocanalostomy and a thread mediated dilation of Schlemm's canal and its collector channels. If the anterior chamber pressure temporarily lowers the level of the venous capillary pressure, it is consistent with a patent piping system when a reverse flow with blood reflux into the anterior chamber can be observed as long as a minimal physiological pressure gradient from the anterior chamber in the direction of channel Schlemm's canal has been restored. Thus, in the authors opinion, anterior chamber haemorrhage shows the desired consistency of the water draining system and should therefore logically be expected after each successful operation in all cases where hypotony in the postoperative period occurs.
PURPOSE To evaluate the efficacy of achieving a 360degree ab externo trabeculectomy using an illuminated ophthalmic microcatheter for the treatment of primary congenital glaucoma. METHODS This retrospective, consecutive case series included 16 eyes of 10 patients <3 years of age at the time of surgery and diagnosed with primary congenital glaucoma. All patients underwent a trabeculectomy via microcatheter with the intent of catheterizing the full circumference of Schlemm’s canal and rupturing the entire canal in a single procedure. The main outcome measure was the success rate of achieving a complete 360 as compared to a partial trabeculectomy. Secondary outcome measures included intraocular pressure
(IOP), glaucoma medication usage, and adverse events. Clinical examination data are reported up to 12 months postoperatively. RESULTS Of 16 eyes included, 12 (75%) achieved a complete 360 trabeculectomyusing the microcatheter; 4 of 16 eyes (25%) achieved a partial trabeculectomy. For all treated eyes the postoperative reduction in IOP from baseline was statistically significant at the 1-, 3-, and 6-month follow-up visits (p <0.001). At 6 months, IOP was significantly lower in the complete as compared to the partial trabeculectomy cohort (p = 0.03). CONCLUSIONS A complete or partial trabeculectomy was safely completed in eyes with primary congenital glaucoma using a microcatheter with an illuminated, atraumatic tip.
PURPOSE. To assess the aqueous outflow pathway in primary open-angle glaucoma (POAG) through provocative gonioscopy and channelography with a flexible microcatheter and fluorescein tracer during canaloplasty.
METHODS. One eye each was randomly selected from 28 consecutive black African POAG patients undergoing canaloplasty. Provocative gonioscopy was performed at the beginning of surgery, and blood reflux from collector channels into Schlemm’s canal (SC) was semiquantitatively evaluated. During canaloplasty, a flexible microcatheter injected fluorescein tracer stepwise into SC. The outflow pathway parameters of interest were blood reflux, transtrabecular passage of fluorescein, and episcleral vein filling.
RESULTS. Mean age, intraocular pressure (IOP), and cup-to-disc ratio were 45.9 years (SD +/- 13.3), 41.0 mm Hg (SD+/- 11.9), and 0.78 (SD+/- 0.22), respectively. Mean IOP (P <0.001) and episcleral venous egress (P = 0.01) correlated significantly with blood reflux, but cup-to-disc ratio (P = 0.71), age (P =0.70), and fluorescein diffusion (P =0.90) did not. A multinomial regression model showed that higher IOP (P < 0.001, OR, 1.687; 95% CI, 1.151–2.472) was strongly associated with poor blood reflux, independent of the patient’s age (P = 0.383, OR, 0.942; 95% CI, 0.823–1.078). No correlation was found between preoperative IOP, transtrabecular passage, episcleral venous egress, and cup-to-disc ratio. The mean IOP was 17.5 mm Hg (SD +/- 3.7) 6 months after surgery. The level of IOP after surgery correlated with the grade of blood reflux and episcleral venous egress (P <0.001).
CONCLUSIONS. High mean IOP may be associated with poor blood reflux and filling of SC. A collapsed canal, probably secondary to high IOP, may be an underestimated sign in black
African patients with POAG. The quality of blood reflux and episcleral venous egress may both be predictive of the level of IOP after surgery. Provocative gonioscopy and channelography may reflect the function of the outflow pathway and may be
helpful in assessing the surgical outcome of canaloplasty.
Prostaglandin F2 alpha (PGF2a) analogues including bimatoprost and travoprost are used worldwide, often as first line topical treatments for glaucoma. We present 2 cases of a newly described side effect of both these topical agents in terms of periorbital fat atrophy. This visually noticeable side effect had features demonstrable on MRI scanning. The periorbital fat atrophy is most apparent with uniocular use and both doctors and patients need to be aware of this side effect before commencing treatment. The effects, however, appear to be reversible with treatment cessation.
Purpose: To compare the safety and efficacy of two polypropylene (Prolene) sutures for tensioning of the inner wall of Schlemm’s canal (SC) in black African patients with primary open-angle glaucoma (POAG) undergoing canaloplasty.
Methods: In a prospective randomised trial of 90 patients, canaloplasty was performed with a flexible microcatheter (iTrack-250A) and sodium hyaluronidate 1.4% (Healon GV). After complete circumferential dilatation of the SC, a Prolene suture, either 6–0 Prolene (group 1) or 10–0 Prolene (group 2), was retracted through the SC and tightened leaving tension on the canal and trabecular meshwork. Nd:YAG laser goniopuncture was not performed postoperatively. Results The mean preoperative intraocular pressure (IOP) was 42.7mmHg±12.5 (SD) in group 1 and 45.0mmHg±12.1 (SD) in group 2 (P=0.70). The mean postoperative IOP without medications was 18.4mmHg±7.1 (SD) in group 1 and 16.4mmHg±6.6 (SD) in group 2 at 1 month (P=0.10), 19.2mmHg±6.4 (SD) in group 1 and 16.4mmHg±4.9 (SD) at 15 months (P=0.04). Pressures equal or less than 21, 18, and 16mmHg without medications (complete success) at 12 months were 51.0% (95% confidence interval (CI) 0.35–0.73), 34.1% (95% CI 0.21–0.56), and 21.2% (95% CI 0.11–0.42) in group 1, and 76.9% (95% CI 0.62–0.96), 68.8% (95% CI 0.54–0.89), and 53.6% (95% CI 0.38–0.76) in group 2, respectively. In the Cox regression analysis, IOP <18mmHg without medications depended significantly on the type of Prolene (hazard ratio (HR) 2.60, 95% CI 1.24–5.46, P=0.01) and age (HR 1.3, 95% CI 1.03–1.86, P=0.03), but not on preoperative IOP (HR 1.01, 95% CI 0.99–1.04, P=0.16) and gender (HR 0.67, 95% CI 0.34–1.33, P=0.26). No filtering bleb was observed. Intra- and postoperative complications were similarly rare in the two groups and included partial ‘cheese-wiring’ (2), Descemet’s rupture (2), and hyphaema (3). Conclusions: In this clinical trial, IOP reduction was substantial in canaloplasty and slightly greater in combination with 10–0
Prolene than 6–0 Prolene sutures at an equally low complication rate. Younger age, but not the level of IOP at surgery, had a positive effect on the amount of IOP reduction, thus suggesting that an early surgical intervention to re-establish physiological outflow offers the best prognosis.
The coincidence of cataract and glaucoma is increasing due to population development. Trabeculectomy is still the most commonly used procedure in combined glaucoma-cataract surgery. However, a two-step approach, starting with cataract surgery should be preferred to minimize the risk of secondary filtering bleb scarring. Postoperative fibrin exudation and the complication rate are more pronounced after combined trabeculectomy compared to combined trabeculotomy and non-penetrating glaucoma surgery. Canaloplasty is a new innovative non-penetrating glaucoma procedure. The results after canaloplasty show an even lower intraocular pressure (IOP) after combined procedures compared to canaloplasty alone. Long-term results have to confirm a sustained decrease of IOP. Surgery of the chamber angle combined with cataract surgery has hardly any complications and preserves the conjunctiva. It also allows medication to be saved and more invasive surgery to be postponed.
Background: The aim of this study is to present a new approach to visualize the aqueous outflow system during glaucoma surgery using a flexible microcatheter and fluorescein, called channelography. Patients and Methods: Schlemm’s canal was unroofed in a standard nonpenetrating dissection technique in patients undergoing canaloplasty. A flexible microcatheter (iTrack™ 250A) was introduced into the canal and advanced 360°. Fluorescein sodium tracer was injected through the microcatheter during cannulation and the aqueous outflow pathway was video-recorded and evaluated. Results: In the early phases, episcleral veins which were thinner, branched and fairly straight originating from the limbus could clearly be distinguished from ciliary veins which were thicker, tortuous vessels leaving posterior to the limbus. The filling quality of the episcleral veins varied among glaucoma patients. The permeability of the trabecular meshwork/inner wall of Schlemm’s canal determined by fluorescein diffusion into the anterior
chamber differed in this regard as well. In the late phases, the sclera stained with fluorescein, and no details were detectable. Conclusions: This qualitative in-vivo method was simple, safe, and enabled us to visualize the details of the aqueous outflow system during canaloplasty. Filling characteristics of episcleral venous network as well as trans-trabecular diffusion may reflect the clinical status of the outflow pathway in glaucoma patients, and may be helpful in the prediction of the surgical outcome in canaloplasty
Open angle glaucoma (OAG) necessitating surgery has traditionally been treated with filtering procedures using antifibrotics. Unfortunately, such filtering procedures are not without the risk of postsurgical complications. Increasing interest in blebless surgery has led to innovative surgical procedures aimed at rejuvenating the natural trabeculo canalicular outflow pathway. Circumferential catheterization with suture tensioning of Schlemm's canal has emerged as a safe and effective way to surgically treat OAG.
PURPOSE: o evaluate 2-year postsurgical safety and efficacy of canaloplasty (circumferential viscodilation and tensioning of the inner wall of Schlemm canal) to treat open-angle glaucoma (OAG).
SETTING: Multicenter surgical sites. METHODS: This international prospective study comprised adult OAG patients having glaucoma surgery or combined glaucoma-cataract surgery. Qualifying preoperative intraocular pressure (IOP) was at least 16 mm Hg and historical IOP, at least 21 mm Hg. The full circumference of the canal was viscodilated and a trabecular tensioning suture placed with a microcatheter. Primary outcome measures included IOP and glaucoma medication use.
RESULTS: At 24 months, all 127 eyes (127 patients) had a mean IOP of 16.0 mm Hg +/- 4.2 (SD) and mean glaucoma medication use of 0.5 +/- 0.8 (baseline values 23.6 +/- 4.8 mm Hg and 1.9 +/- 0.8 medications). Eyes with canaloplasty alone had a mean IOP of 16.3 +/- 3.7 mm Hg and 0.6 +/- 0.8 medications (baseline values 23.2 +/- 4.0 mm Hg and 2.0 +/- 0.8 medications). Eyes with combined glaucoma-cataract surgery had a mean IOP of 13.4 +/- 4.0 mm Hg and 0.2 +/- 0.4 medications (baseline values 23.1 +/- 5.5 mm Hg and 1.7 +/- 1.0 medications). The IOP and medication use results at all time points were statistically significant versus baseline (P <.001). The late postoperative follow-up identified 3 patients with elevated IOP. No other serious ocular or nonocular complications were reported.
CONCLUSION: Canaloplasty was safe and effective in reducing IOP in adult patients with OAG.
Purpose of review: Outflow procedures for glaucoma surgery have remained popular in the last decade, including trabeculectomy, glaucoma drainage devices, and deep sclerectomy/viscocanalostomy. In the last few years, the surgical armamentarium for glaucoma has vastly increased. Surgeons are using more procedures aimed at creating bleb-free surgery. Schlemm’s canal surgery is experiencing a renaissance. This article
concentrates on three of the more commonly performed canal procedures:
trabeculotomy ab interno (Trabectome), Canaloplasty, and trabeculotomy ab externo. Recent findings: Trabeculotomy ab interno performed with the Trabectome has been shown to lower intraocular pressure (IOP) almost 40% by 12 months with minimal complications. Trabectome alone, as well as combined with cataract surgery, appears to lower IOP quite well. Canaloplasty has also been shown to lower IOP by 38%and combined with cataract surgery, IOP was lowered 44% at 24 months. Trabeculotomy lowers IOP well, especially in older adults. Phacotrabeculotomy lowers IOP to 21mmHg or less in 84% of patients with supplemental use of medications, and in 36% of patients without at 3 years.
Summary: Canal surgery has proven to be an alternative to traditional glaucoma surgery, lowering IOP relatively well. Surgeons must be comfortable with the anatomy and proceed
with the procedure in eyes that are amenable to various new surgical advances.
Purpose: To compare outcomes across Trabectome, iScience (canaloplasty), trabeculectomy, and aqueous shunts regarding intraocular pressure (IOP), adjunctive medications, and complications after glaucoma-only and combined glaucoma-phacoemulsification surgeries for open-angle glaucomas.
Method: A literature review compares success rates, complications, efficacy, and limitations of traditional and novel glaucoma surgical procedures.
Results: Trabectome and canaloplasty provide modest IOP reduction with minimal intraoperative or postoperative complications. Results of Baerveldt glaucoma implant IOP reduction are comparable to trabeculectomy, but typically this shunt requires more postoperative IOP-lowering medication to achieve a success rate comparable to trabeculectomy.
Conclusion: Trabeculectomy is still the most effective IOP-lowering procedure performed today but continues to have the highest serious complication rates. Trabectome and canaloplasty are reasonable surgical therapy choices for patients in which IOPs in the mid-teens seem adequate.
Abnormally high resistance to aqueous humor drainage via the trabecular meshwork and Schlemm’s canal is highly correlated with the development of primary open-angle glaucoma. Contractility of the actomyosin system in the trabecular cells or inner wall endothelium of Schlemm’s canal is an important factor in the regulation of outflow resistance. Cytoskeletal agents, affecting F-actin integrity or actomyosin contractility, or gene therapies, employing overexpression of caldesmon or Rho-A inhibition, can decrease outflow resistance in the drainage pathway. In this review, we discuss the mechanisms underlying these and similar effects on trabecular outflow resistance in living animals and/or in cultured ocular anterior segments from enucleated animal or human eyes
The goal of glaucoma surgery should be the preservation of visual function, the avoidance of sight-threatening complications and the preservation of the quality of life of the patient. Curiously, the majority of glaucoma surgeons still consider trabeculectomy the best surgical option for their patients, despite evidence that trabeculectomy cannot meet these goals.
Objective: Patients undergoing primary Canaloplasty for open angle glaucoma, under the care of the two authors, were entered into a common data base. The two authors also pooled their results at three years, from a prospective audit of patients undergoing Viscocanalostomy, from the same sites, in order to provide a comparison of the successes and complications of the two procedures.
Patients and methods: Surgery was carried at: Warrington Hospital, Warrington, UK; Spire Cheshire Hospital, Stretton, UK; Augencentrum Porz, Cologne, Germany and University Eye Hospital Padua, Italy, between May 1997 and May 2008.
Ninety seven eyes of 75 patients underwent Canaloplasty with a mean age of 67 years (range 41 to 85 years) and a mean follow up of 19 months (range 6 months to 3 years). One hundred and twenty eyes of 92 patients had undergone Viscocanalostomy with a mean age of 68 years (range 26 to 92 years) and a mean follow up of 22 months (range: 3 months to 3 years).
Results: There were no statistically significant differences in the mean pre-operative IOP and number of medications between groups. Both Canaloplasty and Viscocanalostomy groups showed a statistically significant reduction in IOP (t = 19.25. p < 0.05 and 15.54. p < 0.05 respectively) and number of medications (t = 21.18 p < 0.05 and 23.04 p < 0.05 respectively) from pre-operative levels. There was a statistically significant difference in favour of the Canaloplasty group in post-operative reduction of both IOP and number of medications compared with the Viscocanalostomy group (Mann-Whitney U 3940.5 and 4109.5 p = < .001 respectively). Of the 97 eyes that underwent Canaloplasty, using the criteria of success as ≤ 21 mm Hg, a success rate of 97% with medication and 92% with no medication was achieved. When success is defined at ≤ 17 mm Hg, the success rate was 87% with medication and 83% with no medication. For the 120 eyes undergoing Viscocanalostomy, using the criteria of success as ≤ 21 mm Hg, a success rate of 96% on medication and 55% with no medication was achieved. However, when success is defined at ≤ 17 mm Hg the success rate drops to 68% on medication and 42% with no medication. There was a statistically significant difference between groups in favour of the Canaloplasty group in the number of patients achieving a post-operative IOP of 17mm Hg or less (t = 2.55 p = .001).
Conclusions: The results reported here show that both Viscocanalostomy and Canaloplasty are safe and effective surgical procedures for the management of Primary Open Angle Glaucoma with fewer complications than the current literature states for trabeculectomy. Moreover, when the results of these two groups of similar patients are compared, Canaloplasty produced significantly better results than Viscocanalostomy.
PURPOSE. To understand how hydrodynamic and morphologic changes in the aqueous humor outflow pathway contribute to decreased aqueous humor outflow facility after acute elevation of intraocular pressure (IOP) in bovine eyes.
METHODS. Enucleated bovine eyes were perfused at 1 of 4 different pressures (7, 15, 30, 45 mm Hg) while outflow facility was continuously recorded. Dulbecco PBS + 5.5 mM glucose containing fluorescent microspheres (0.5 µm, 0.002% vol/vol) was perfused to outline aqueous outflow patterns, followed by perfusion-fixation. Confocal images were taken along the inner wall (IW) of the aqueous plexus (AP) in radial and frontal sections. Percentage effective filtration length (PEFL; IW length exhibiting tracer labeling/total length of IW) was measured. Herniations of IW into collector channel (CC) ostia were examined
and graded for each eye by light microscopy. RESULTS. Increasing IOP from 7 to 45 mm Hg coincided with a twofold decrease in outflow facility (P < 0.0001), a 33% to 57% decrease in PEFL with tracer confined more to the vicinity of CC ostia, progressive collapse of the AP, and increasing percentage of CC ostia exhibiting herniations (from 15.6%+/- 6.5% at 7 mm Hg to 95%+/-2.3% at 30 mm Hg [P <10 -4], reaching 100% at 45 mm Hg).
CONCLUSIONS. Decreasing outflow facility during acute IOP elevation coincides with a reduction in available area for aqueous humor outflow and the confinement of outflow to the vicinity of CC ostia. These hydrodynamic changes are likely driven by morphologic changes associated with AP collapse and herniation of IW of AP into CC ostia.
PURPOSE: To evaluate the safety and efficacy of circumferential viscodilation and tensioning of the inner wall of Schlemm's canal in a new surgical procedure for the treatment of open-angle glaucoma (OAG). SETTING: Fourteen clinical sites in the United States and Germany.
METHODS: In this international multicenter prospective study of adult patients with OAG having glaucoma surgery, patients with qualifying preoperative intraocular pressure (IOP) of at least 16 mm Hg or higher and open angles were eligible. Evaluation was performed at baseline and 1 day, 1 week, and 1, 3, 6, and 12 months preoperatively. After a nonpenetrating dissection technique to expose Schlemm's canal was performed, a flexible microcatheter (iTrack 250A, iScience Interventional) was used to dilate the full circumference of the canal by injecting sodium hyaluronate 1.4% (Healon GV) during catheterization. A suture loop was placed in the canal to apply tension to the trabecular meshwork. High-resolution ultrasound imaging was used to assess Schlemm's canal and anterior segment angle morphology, including distension of the trabecular meshwork caused by the tensioning suture. Data analysis was performed in 2 groups: Group 1, in which patients met all inclusion criteria, and Group 2, made up of Group 1 patients who had successful suture placement.
RESULTS: Group 1 comprised 94 patients and Group 2, 74 patients. The mean baseline IOP in Group 1 was 24.7 mm Hg+/-4.8 (SD) on a mean of 1.9+/-1.0 medications per patient. In Group 2 (patients with sutures), the mean IOP was 16.1+/-4.7 mm Hg 3 months postoperatively, 15.6+/-4.0 mm Hg at 6 months, and 15.3+/-3.8 mm Hg at 1 year. Medication use dropped to a mean of 0.6+/-0.9 per patient at 12 months. Suture tensioning was an apparent contributing factor in achieving surgical success. Patients with measurable trabecular meshwork distension from suture tension had a mean IOP of 15.9+/-5.2 mm Hg at 6 months and 14.5+/-3.0 mm Hg at 12 months. Surgical and postsurgical adverse events were reported in 15 of 94 patients (16%) and included hyphema (3), elevated IOP greater than 30 mm Hg (3), Descemet's tear (1), hypotony (1), choroidal effusion (1), and exposed closure suture with eyelid edema and erythema epiphora (1); 4 patients were subsequently converted to trabeculectomy.
CONCLUSION: Circumferential viscodilation and tensioning of Schlemm's canal was a safe and effective surgical procedure to reduce IOP in adult patients with OAG.
PURPOSE: To evaluate the efficacy and safety of primary viscocanalostomy for medically uncontrolled juvenile open-angle glaucoma (JOAG). DESIGN: Prospective, noncomparative, interventional case-series study. METHODS: The study included 20 eyes of 20 consecutive patients with medically uncontrolled JOAG who were treated by viscocanalostomy at one institution. No surgical or laser procedure preceded viscocanalostomy. Surgical outcome was defined as an overall success by the following criteria: no visual field deterioration, no opticneuropathy progression, postoperative intraocular pressure IOP 30% compared with baseline values with or without medication. When medications were not required, success was defined as complete. Cases that did not fulfill the aforementioned criteria and cases in which a surgical revision or further goniopuncture was performed were defined as a failure. RESULTS: Gender distribution was similar. Fourteen eyes belonged to the white race; five eyes belonged to the black race, and one eye belonged to Arab ethnicity. Mean age ( SD) at operation was 33.77 6.16 years, with the mean preoperative IOP ( SD) at 22.9 4.77 mm Hg. Thirty-six months after operation, 16 cases (80%) were considered an overall success. In 11 cases (55%), success was complete. Four cases (20%) were considered failures. No serious complications were documented either during or after operation. In two cases (10%), we documented a spontaneously reabsorbed microhyphema. Trabeculo-Descemet-membrane microperforation occurred in two cases (10%). In two other cases (10%),
Trabeculo-Descemet-membrane perforation occurred and was accompanied by iris prolapse that needed peripheral iridectomy. CONCLUSION: Primary viscocanalostomy can efficiently and safely reduce intraocular pressure in cases of medically uncontrolled JOAG and provide a rational alternative to conventional surgical modalities.
Purpose: To describe a new aqueous outflow model involving a mechanical pump.
Materials and Methods: Laboratory materials include human and monkey eyes; methods include the dissecting microscope, light microscopy, scanning electron microscopy, transmission electron microscopy, and tracer studies. Clinical methods involve human subject slit lamp, gonioscopy, and operating microscope examination. Results: Laboratory evidence demonstrates that aqueous outflow tissues are responsive to intraocular pressure induced deformation. Deformation occurs in response to small pressure gradients. Laboratory evidence also demonstrates the presence of valves discharging aqueous to Schlemm’s canal. The laboratory model predicts pulsatile aqueous discharge in vivo. Clinical in vivo evidence demonstrates pulsatile aqueous flow from the anterior chamber into Schlemm’s canal, from Schlemm’s canal into collector channels, and from Schlemm’s canal into aqueous and episcleral veins, all synchronous with the ocular pulse.
Conclusions: Aqueous outflow tissue deformation caused by normal intraocular pressure transients induces pulsatile one-way discharge of aqueous to the vascular system. The model identifies biomechanical coupling of intraocular pressure with aqueous outflow tissue deformation and also sites of high flow capable of inducing shear stress. These mechanotransduction mechanisms, well characterized as a means of controlling pressure and flow in the vascular system, also provide a means of regulatory feedback to control intraocular pressure and aqueous flow.
The optimal treatment for bleb-related infections is evolving but consensus is that a high degree of vigilance and aggressive treatment are key to minimizing the potentially blinding nature of this complication. It is important to note that those glaucoma procedures that provide the lowest intraocular pressure are often those that predispose to bleb-related infections
Objectives: To determine the incidence of late-onset bleb-related complications following trabeculectomy with mitomycin and to report the management and outcome of bleb leaks following trabeculectomy with mitomycin. METHODS:A retrospective medical record review of all patients who underwent trabeculectomy with mitomycin from June 1, 1991, through April 30, 1998, at our institution was performed. The Kaplan-Meier survival method was used to estimate the probability of (1) endophthalmitis, (2) blebitis, (3) a bleb leak, and (4) the combined outcome (the first occurrence of a bleb leak, blebitis, or endophthalmitis). This survival analysis included only the first trabeculectomy in an eye, with at least 3 months of follow-up during the study period. A separate description of bleb leak management and outcome was performed. RESULTS:Two hundred thirty-nine eyes of 198 patients were included in the survival analysis. The average follow-up was 2.7 (range, 0.3-7.3) years. Twenty eyes (8%) from 19 patients experienced a bleb leak; the adjusted incidence was 3.2% per patient-year. Five eyes (2%) had an episode of blebitis. Eight eyes (3%) experienced an episode of endophthalmitis; the follow-up adjusted incidence (number of events per patient-year) was 1.3%. Twenty-seven eyes (11%) from 26 patients had at least 1 of the complications of a bleb leak, blebitis, or endophthalmitis; the adjusted incidence was 4.4% per patient-year. A Kaplan-Meier analysis estimated the 5-year probability of developing a bleb leak, blebitis, or endophthalmitis to be 17.9%, 6.3%, and 7.5%, respectively. Two hundred fifty-eight trabeculectomies in 242 eyes of 198 patients were included in the description of bleb leak management and outcome. Bleb leaks occurred in 22 eyes (9% of the 258 trabeculectomies). Seventeen eyes were successfully treated with office-based measures, and 4 ultimately underwent surgical bleb revision. One eye without infection continued to leak after 11 months of office-based therapy. CONCLUSIONS:There is significant morbidity associated with a trabeculectomy with mitomycin. The incidence of a bleb leak or an infection continues at a fairly constant rate over time, such that at 5 years, up to 23% of all patients might develop one of these complications. An isolated bleb leak seems to be a relatively benign condition, as three quarters resolve with office-based methods.
Objective: To determine the risk factors for late-onset infection following glaucoma filtration surgery. Methods: We performed a case-control study comparing 131 cases of late-onset infection collected from 27 surgeons at 10 centers with 500 controls matched for date of surgery and surgeon. The criterion for the presence of infection was severe anterior chamber reaction occurring later than 4 weeks after surgery. An opaque bleb and positive culture results were not required for diagnosis. Risk factors were identified by univariate and multivariate logistic regression analyses.
Results: Some of the risk factors that were statistically significant in the multivariate model after adjusting for age, race, and sex were (1) performance of a fullthickness rather than a guarded procedure (risk ratio [RR], 13.1; 95% confidence interval [CI], 2.12-80.9), (2) filtration surgery performed without concurrent cataract surgery (RR, 2.25; 95% CI, 1.24-4.08), (3) use of mitomycin (RR, 2.48; 95% CI, 1.06-5.83), (4) intermittent use of antibiotics after surgery (RR, 2.10; 95% CI, 1.09- 4.02), and (5) continuous use of antibiotics after surgery (RR, 5.94; 95% CI, 2.09-16.9). Conclusions: Eyes undergoing full-thickness procedures or filtration surgery without cataract extraction are at increased risk for late infection. Intraoperative mitomycin and episodic or continuous antibiotic use after the postoperative period are associated with an increased risk of infection.
The aqueous in freshly killed cynomolgus monkeys ivas replaced hy a solution of JS5I-albumin and j:"I-diodone (iodopyracet). An inflow of this solution into the anterior chamber was produced by a horizontal buret placed above the eye, and at the same time the eye was continuously washed through with the radioactive solution at a high rate by a push-pull arrangement. Fluid was collected from the denuded anterior sclera in 1 minute samples over a period of 25 minutes. The same type of experiments was performed with JS5I—gamma globulin and J3JI-albumin. In the effluent, albumin and gamma globulin reached an apparently steady concentration after 1 minute, while throughout the experiments the diodone concentration in the effluent remained lower than expected from a bulk flow through well-defined channels. The low concentration was due to a rapid diffusion of diodone into the tissues of the limbus region. The labeled albumin entered the uvea and the sclera in such amounts as to indicate that about 20 per cent of the labeled fluid had passed out by way of unconventional uveoscleral routes. The results suggest that more than 90 per cent of the conventional drainage was carried by pores with an apparent diameter of more than 0.16 µ.
IN previous studies of this region (Ashton 1951, 1952), it has been shown that the canal of Schlemm and its efferent connections may be clearly demonstrated by Neoprene latex casts, prepared by direct injection of the canal followed by enzyme digestion of the ocular tissues. Over 200 casts have now been studied by this technique and while the preparations in the main confirm the anatomical accounts of earlier workers, who used serial sections or injections of ink and gelatin followed by clearing, they have the advantage of showing the exact anatomy of the canal in its entirety and in a stereoscopic way that can be readily appreciated. The study has revealed some minor but important deviations from the classical descriptions and these will be discussed in a subsequent communication dealing in detail with the structure and connections of the canal itself. It is the purpose of this paper to describe the arterial relationships of Schlemm's canal as observed in cast preparations.
An anatomical study of six aqueous veins by means of Neoprene casts has already been reported (Ashton, 1951); it was shown that two arose directly from Schlemm's canal while the remaining four communicated with it indirectly via anastomotic branches between the superficial and deep scleral plexuses. All the aqueous veins were of the striated or laminated variety. It has now been possible to study the anatomy of a pure aqueous vein by the same technique and the purpose of this paper is to report the findings.