Comparison of Surgical Outcomes Between Canaloplasty and Trabeculectomy at 12 Months' Follow-Up

Historical and Contemporary Debates in Schlemm's Canal-Based MIGS

Glaucoma is one of the primary causes of blindness worldwide. Canal opening surgery, a type of minimally invasive glaucoma surgery (MIGS) applied in cases of mild to moderate glaucoma, has gained increasing popularity in recent years due to its efficacy in reducing the intraocular pressure, its safety profile, the simplicity of its technique, and the reduced likelihood of compromised vision. Nevertheless, the existing body of histopathological studies remains insufficient for a comprehensive understanding of post-surgical wound healing. Consequently, debates persist among researchers regarding the mechanism through which Schlemm's canal opening surgery reduces the intraocular pressure, as well as the surgical techniques that may impact the outcomes and the factors influencing surgical success. As the history of MIGS is relatively short and lacks sufficient systemic reviews or meta-analyses evaluating the influence of individual factors, this review was conducted to illuminate the disparities in researchers' opinions at the current stage of research.

Long-term outcomes of canaloplasty and phaco-canaloplasty in the treatment of open angle glaucoma: a single-surgeon experience

PURPOSE

To evaluate and compare the long-term outcomes of canaloplasty and phaco-canaloplasty in the treatment of open angle glaucoma and assess the prognostic factors associated with surgical outcome.

METHODS

A 48-month retrospective analysis was performed on n = 133 open angle glaucoma eyes treated with canaloplasty and n = 57 open angle glaucoma eyes treated with phaco-canaloplasty by a single surgeon. Surgical success was defined according to six criteria, achieving a target intraocular pressure (IOP) ≤ 21, 18 or 15 mmHg on glaucoma medications (qualified success) or without any further treatment (complete success), including laser therapy or surgery. Kaplan-Meier survival analysis and Cox regression analysis were performed to evaluate surgical success and preoperative factors associated with surgical outcome. Surgical complications in the early postoperative period were compared between canaloplasty and phaco-canaloplasty.

RESULTS

Canaloplasty and phaco-canaloplasty significantly reduced postoperative IOP and number of glaucoma medications (p = 0.001 for both). Phaco-canaloplasty showed higher rates of cumulative surgical success over canaloplasty, but only for target IOP ≤ 21 and ≤ 18 (p = 0.018 and p = 0.011, respectively). A preoperative number of > 4 glaucoma medications predicted surgical failure. Phaco-canaloplasty was associated with a higher rate of IOP peaks in the first month compared with canaloplasty (40.4% vs 12.7%, p = 0.000).

CONCLUSION

Canaloplasty and phaco-canaloplasty demonstrated long-term efficacy in the treatment of open angle glaucoma, with phaco-canaloplasty showing higher rates of surgical success compared to canaloplasty, but not for target IOPs lower than 16 mmHg. Patients on more than 4 preoperative glaucoma medications may not be good candidates for canaloplasty and may benefit from other surgical options.

New suture probe canaloplasty combined with suprachoroidal collagen implantation

PURPOSE

To present the modified surgery technique of new suture probe canaloplasty with a specially prepared monofilament 4.0 polypropylene suture combined with suprachoroidal drainage (ScD) and collagen sheet implantation for non-penetrating glaucoma surgery.

METHODS

Prospective study with a twelve months follow-up. A standard 4/0 polypropylene suture (ProleneTM by Ethicon; thickness: approximately 250 m) is cut and shaped with an ophthalmic knife (MANI® Crescent Knife, Mani Inc 8-3 Kiyohara Industrial Park, Utsunomiya, Tochigi 321-3231, Japan) to create a blunt end without sharp or compressed edges. This improves suture probe canaloplasty by providing a more stable and smoother probing device. Schlemm's canal is prepared using the standard technique of canaloplasty with suprachoroidal drainage. Then, instead of using the canaloplasty microcatheter or the previously published 6/0 double-helix suture, Schlemm's canal is probed with the blunt ending of the 4/0 Prolene suture. After successful 360-degree probing, a doubled 10/0 polypropylene tension suture is threaded through the tip of the 4/0 suture. The 4/0 suture is then pulled back and the 10/0 tension sutures are tied at both ends to tension Schlemm's canal. A special collagen sheet (Ologen®) is placed in suprachoroidal space, and the scleral flap is firmly sewed.

RESULTS

115 eyes were included in this prospective study. In 113 cases the Schlemm's canal could completely be probed with the suture probe and canaloplasty with ScD and collagen sheet implantation succeeded. In two cases the intervention was transformed to 360-degree suture trabeculotomy due to an intraoperative cheese-wiring. Twelve months after successful new suture probe canaloplasty with ScD and Collagen Implantation the IOP had decreased by 37.1% (from 21.6 ± 6.0 mmHg with 3.3 different IOP lowering eye drops to 13.5 ± 3.5 mmHg with 1.0 eye drops). 16 Patients did not achieve sufficient IOP levels and underwent 360-degree suture trabeculotomy during the follow-up. One patient had to be treated with further glaucoma surgery to achieve a sufficient IOP level. Complications were hyphema, postoperative IOP elevation and transient hypotony. No serious or sight-threatening complications occurred.

CONCLUSION

New suture probe canaloplasty with ScD and collagen sheet implantation yields the opportunity to conduct a cost-effective canaloplasty easier and less complicated than with the previously described method with the twisted 6/0 suture. The safety profile and IOP lowering effect is comparable. In cases where complete probing fails, there is still the opportunity to switch to suture trabeculotomy over the majorly probed part of Schlemm's canal. The pressure lowering effect of the deep sclerectomy with ScD and suprachoroidal collagen sheet implant seems to have an additional impact on the sufficient pressure lowering procedure.

A Review of Canaloplasty in the Treatment and Management of Glaucoma

Aim

To review the published literature evaluating the safety and efficacy outcomes of canaloplasty performed in the treatment of glaucoma.

Background

Canaloplasty is a nonpenetrating glaucoma procedure involving combined 360° circumnavigation and viscodilation of Schlemm's canal. The procedure may be performed under an ab externo (with tensioning suture) or ab-interno (conjunctiva-sparing) approach. Given the wide variety of glaucoma procedure types and approaches, further investigation into the role of canaloplasty in ophthalmological practice is warranted. The objectives of this narrative review are to synthesize the existing literature in order to investigate indications, safety and efficacy outcomes, and the optimal place of canaloplasty in glaucoma treatment and management.

Review of results

A total of 60 articles were included in this review. Both ab externo and ab-interno canaloplasty (ABiC) were found to be significantly effective at reducing intraocular pressure (IOP) and glaucoma medication burdens in patients with mild-to-moderate open-angle glaucoma (OAG). These findings remained consistent regardless of phacoemulsification status. ABiC was found to exhibit a safety profile favorable compared to trabeculectomy and comparable to minimally invasive trabecular bypass implants.

Conclusion

Canaloplasty is a nonpenetrating surgical intervention that is highly effective in treating patients with mild-to-moderate OAG across a large variety of clinical scenarios.

Clinical significance

These findings support the clinical use of canaloplasty in ophthalmological practice, clarify its patient profile, and compare procedural outcomes to other minimally invasive glaucoma surgery (MIGS) devices on the market.

How to cite this article

Wagner IV, Towne C, Saade MC, et al. A Review of Canaloplasty in the Treatment and Management of Glaucoma. J Curr Glaucoma Pract 2024;18(2):79-85.

Descemet's Membrane Detachment during Phacocanaloplasty: Case Series and In-Depth Literature Review

This article presents three cases of Descemet's membrane detachment (DMD) occurring during 'ab externo' phacocanaloplasty procedures in three patients with uncontrolled primary open-angle glaucoma (OAG) and discusses the management of this condition by reviewing the available literature. Following a successful 360° cannulation of Schlemm's canal (SC), the microcatheter was withdrawn while an ophthalmic viscosurgical device (OVD) was injected into the canal. During passage through the inferonasal quadrant, a spontaneous separation of the posterior layer of the cornea was observed. Each case was managed differently after diagnosis, with the third case being drained intraoperatively based on experience gained from the previous cases. On the first postoperative day, slit-lamp biomicroscopy (BMC) revealed multiple DMDs in case one and a hyphema in the lower third of a deep anterior chamber. In the other two cases, a single DMD was observed. The second case developed hemorrhagic Descemet membrane detachment (HDMD), while the other two were non-hemorrhagic. In all three cases, anterior segment optical coherence tomography (AS-OCT) revealed the presence of retrocorneal hyperreflective membranes indicative of DMDs. These membranes were located in the periphery of the cornea and did not impact the visual axis. After evaluation, a small incision was made in the inferotemporal DMD of the first case. However, for the two remaining cases, a strategy of watchful waiting was deemed appropriate due to the location and size of the DMDs, as they did not affect the best-corrected visual acuity (BCVA). Over time, the patients demonstrated progressive improvement with a gradual reduction in the size of the DMDs.

Advances in Canaloplasty-Modified Techniques Yield Strong Pressure Reduction with Low Risk Profile

For decades, trabeculectomy (TE) was considered the gold standard for surgical treatment of open-angle glaucoma owing to its powerful intraocular pressure (IOP)-lowering potency. However, owing to the invasive nature and high-risk profile of TE, this standard is changing, and minimally invasive procedures are becoming more preferable. In particular, canaloplasty (CP) has been established as a much gentler alternative in everyday life and is under development as a full-fledged replacement. This technique involves probing Schlemm's canal with a microcatheter and inserting a pouch suture that places the trabecular meshwork under permanent tension. It aims to restore the natural outflow pathways of the aqueous humor and is independent of external wound healing. This physiological approach results in a significantly lower complication rate and allows considerably simplified perioperative management. There is now extensive evidence that canaloplasty achieves sufficient pressure reduction as well as a significant reduction in postoperative glaucoma medications. Unlike MIGS procedures, the indication is not only mild to moderate glaucoma; today, even advanced glaucoma benefits from the very low hypotony rate, which largely avoids a wipeout phenomenon. However, approximately half of patients are not completely medication-free after canaloplasty. As a consequence, a number of canaloplasty modifications have been developed with the goal of further enhancing the IOP-lowering effect while avoiding the risk of serious complications. By combining canaloplasty with the newly developed suprachoroidal drainage procedure, the individual improvements in trabecular facility and uveoscleral outflow facility appear to have an additive effect. Thus, for the first time, an IOP-lowering effect comparable to a successful trabeculectomy can be achieved. Other implant modifications also enhance the potential of canaloplasty or offer additional benefits such as the possibility of telemetric IOP self-measurement by the patient. This article reviews the modifications of canaloplasty, which has the potential to become a new gold standard in glaucoma surgery via stepwise refinement.

Long-Term Efficacy and Safety of Modified Canaloplasty Versus Trabeculectomy in Open-Angle Glaucoma

BACKGROUND

To evaluate the long-term efficacy and safety of modified canaloplasty versus trabeculectomy in open-angle glaucoma.

METHODS

In total, 210 subjects with open-angle glaucoma were included. 70 were treated with Mitomycin C-augmented modified canaloplasty with enhanced subconjunctival filtration and 140 with Mitomycin C-augmented trabeculectomy. Cases were matched 1:2 by sex and age.

RESULTS

In canaloplasty and trabeculectomy groups, 61.4% and 57.9% of participants were female. Mean age was 60.0 ± 13.9 and 63.0 ± 12.2 years, median follow-up time was 4.6 [IQR 4.3, 5.05] years and 5.8 [IQR 5.4, 6.3]. Strict success was achieved in 20.0% and 56.4%, complete success in 24.3% and 66.4%, and qualified success in 34.3% and 73.6% (each p < 0.001). Kaplan-Meier survival analysis showed a better survival probability for trabeculectomy than for canaloplasty (p < 0.001) and Cox regression analysis revealed an HR of 6.03 (95%-CI 3.66, 9.93, p < 0.001) after canaloplasty. Trabeculectomy showed superiority in terms of IOP decrease (9.2 ± 7.9 mmHg vs. 13.7 ± 10.4 mmHg, p = 0.002), use of AGM (50.0% vs. 10.7%, p < 0.001), and the number of revision surgeries (41.4% vs. 21.4%, p = 0.004). Occurrence of complications was similar in both groups (14.5% vs. 7.5%, p = 0.19).

CONCLUSIONS

Trabeculectomy showed superiority in efficacy and equality in safety compared to modified canaloplasty.

How Could Medical and Surgical Treatment Affect the Quality of Life in Glaucoma Patients? A Cross-Sectional Study

BACKGROUND

To evaluate and compare the visual function and the quality of life (QoL) in glaucomatous patients treated with topical medical therapy (TMT) alone, canaloplasty (CP), or trabeculectomy (TB).

METHODS

A total of 291 eyes of 167 patients with primary open-angle glaucoma or secondary pseudoexfoliative glaucoma in TMT or surgically treated with CP or TB were included. Eligibility criteria for surgical patients included not needing TMT after surgery. Each patient underwent a visual field assessment and peripapillary retinal nerve fiber layer (pRNFL) optical coherence tomography and filled out the Glaucoma Symptoms Scale (GSS) questionnaire and the 25-Item National Eye Institute Visual Functioning Questionnaire (25-NEI-VFQ). Comparison between the QoL level of the three groups and its correlation with optic nerve's anatomical and functional status was the primary outcome.

RESULTS

CP patients reported the best general vision (p = 0.01), a lower incidence of eye burning (p = 0.03), and the lowest annoyance level of non-visual symptoms (p = 0.006). QoL positively correlated with pRNFL thickness, whereas no correlation was found with visual field damage.

CONCLUSION

CP provides a better QoL when compared both to TB and TMT, regardless of glaucoma stage. pRNFL seems to provide additional information for predicting change in QoL.

A Novel and Reversible Experimental Primate Ocular Hypertension Model: Blocking Schlemm's Canal

INTRODUCTION

The purpose of this study was to establish a novel and reversible experimental ocular hypertension primate model by blocking Schlemm's canal.

METHODS

A model was induced in adult cynomolgus monkeys (n = 4) by blocking Schlemm's canal with an inserted microcatheter (200 μm diameter); it was removed 6 weeks later from one monkey to reverse the elevated intraocular hypertension. All animals were monitored for 11 months; weekly measurements of intraocular pressure and biweekly examinations with spectral domain optical coherence tomography and disc photography were performed. Histopathology of the eye and retinal ganglion cell counts were completed at the end of the study.

RESULTS

The intraocular pressure of the blocked eyes was significantly higher than that of the contralateral eyes at 1 month after the blockage (p < 0.001); the mean intraocular pressure was similar to the contralateral eye from 1 week to 11 months after the microcatheter was removed in monkey A (p = 0.170). The mean intraocular pressure of the blocked eyes of the remaining monkeys was significantly higher than that of the contralateral eyes throughout the follow-up period (p < 0.001). The fundus imaging showed decreases in the retinal nerve fibre layer thickness, and localized defects were observed in two blocked eyes. A histological examination demonstrated that the number of retinal ganglion cells in the blocked eyes of monkeys A, B, and C was significantly decreased compared with the control.

CONCLUSION

Schlemm's canal blockage alone in the monkey model produces sustained elevation of intraocular pressure, which presents a novel animal model for studying the pathogenesis of glaucoma.

[Modifications of canaloplasty : Strong pressure-lowering effect with a low risk profile]

Trabeculectomy still achieves the strongest intraocular pressure (IOP) reduction of all glaucoma surgical techniques, but with the drawback of a significant risk profile. Against this background, canaloplasty has established itself as a much gentler alternative which achieves sufficient IOP reduction and enables a significant reduction in postoperative glaucoma medication. However, approximately half of patients are not completely medication free. In response, a number of modifications have been developed with the goal of further enhancing the IOP-lowering effect of canaloplasty, but without the risk of serious complications. By combining canaloplasty with the newly developed suprachoroidal drainage, a uveoscleral drainage is created in addition to the trabecular outflow improvement, which seems to have an additive effect. Thus, for the first time, an IOP-lowering effect comparable to successful trabeculectomy can be achieved. Numerous other modifications with implants also enhance the potential of canaloplasty or offer other additional benefits such as the possibility of telemetric IOP self-measurement by the patient. The additional creation of a subconjunctival drainage with or without use of cytostatic drugs also seems promising. Ab interno procedures, on the other hand, have limited pressure-lowering potential but may provide some additional benefit in mild glaucoma and in the setting of cataract surgery.

Clinical application of the CO2 laser in Ab externo Schlemm's canal surgery

Purpose

This study aimed to investigate the clinical application of laser as a knife in Ab externo Schlemm's canal (SC) surgery and compare the efficacy and safety of the CO₂ laser with the conventional procedure using a surgical knife.

Methods

Patients who underwent either canaloplasty or trabeculotomy with CO₂ laser system which was used to locate and ablate the outer wall of SC at the time interval between May 2020 and May 2021 were identified, their medical files were reviewed, and their results were compared with conventional surgery group who underwent canaloplasty or trabeculotomy with conventional surgical knife at the same time period. The following datas were conducted and compared: age, sex, intraocular pressure (IOP), number of drugs, best-corrected visual acuity (BCVA), mean deviation and pattern standard deviation of visual field examination, SC opening related complications.

Results

A total of 49 patients (49 eyes) were included in this study, including 23 in the Laser surgery group and 26 in the conventional surgery group. Time for SC opening was 49.33 ± 25.23 s and 116.50 ± 31.79 s for laser surgery group and conventional surgery group, respectively. This difference between the two groups was statistically significant (P < 0.01). Hemorrhage occurred in five eyes during ablation for the laser surgery group and in 24 eyes for the conventional surgery group. In addition, anterior chamber penetration occurred in two cases for the laser surgery group and in six cases for the conventional surgery group. The success rate of identifying and opening outer wall of SC was 91.30% (21 eyes) for the laser surgery group and 76.92% (20 eyes) for the conventional surgery group. The difference between preoperative and postoperative intraocular pressure for each group was statistically significant (P < 0.01), and there were no statistically significant differences across the two groups in terms of postoperative IOP (P = 0.238) and BCVA (P = 0.389).

Conclusion

Compared with the conventional procedure using a surgical knife, CO₂ laser-assisted ablation of the outer wall of SC was less time-consuming and less technically challenging. CO₂ laser-assisted ablation also resulted in fewer complications. Furthermore, it had a shorter learning curve and a higher success rate of identifying and opening SC.

Unmet needs in glaucoma therapy: The potential role of hydrogen sulfide and its delivery strategies

Glaucoma is an optic neuropathy disorder marked by progressive degeneration of the retinal ganglion cells (RGC). It is a leading cause of blindness worldwide, prevailing in around 2.2% of the global population. The hallmark of glaucoma, intraocular pressure (IOP), is governed by the aqueous humor dynamics which plays a crucial role in the pathophysiology of the diesease. Glaucomatous eye has an IOP of more than 22 mmHg as compared to normotensive pressure of 10-21 mmHg. Currently used treatments focus on reducing the elevated IOP through use of classes of drugs that either increase aqueous humor outflow and/or decrease its production. However, effective treatments should not only reduce IOP, but also offer neuroprotection and regeneration of RGCs. Hydrogen Sulfide (H₂S), a gasotransmitter with several endogenous functions in mammalian tissues, is being investigated for its potential application in glaucoma. In addition to decreasing IOP by increasing aqueous humor outflow, it scavenges reactive oxygen species, upregulates the cellular antioxidant glutathione and protects RGCs from excitotoxicity. Despite the potential of H₂S in glaucoma, its delivery to anterior and posterior regions of the eye is a challenge due to its unique physicochemical properties. Firstly, development of any delivery system should not require an aqueous environment since many H₂S donors are susceptible to burst release of the gas in contact with water, causing potential toxicity and adverse effects owing to its inherent toxicity at higher concentrations. Secondly, the release of the gas from the donor needs to be sustained for a prolonged period of time to reduce dosing frequency as per the requirements of regulatory bodies. Lastly, the delivery system should provide adequate bioavailability throughout its period of application. Hence, an ideal delivery system should aim to tackle all the above challenges related to barriers of ocular delivery and physicochemical properties of H₂S itself. This review discusses the therapeutic potential of H₂S, its delivery challenges and strategies to overcome the associated chalenges.

Clinical outcomes of penetrating canaloplasty in patients with traumatic angle recession glaucoma: a prospective interventional case series

BACKGROUND/AIM

To evaluate the clinical outcomes of penetrating canaloplasty in traumatic angle recession glaucoma at 1 year.

METHODS

Patients with angle recession glaucoma underwent penetrating canaloplasty, a new Schlemm's canal-based internal drainage procedure, which creates a direct canal for flow of aqueous humour from the anterior chamber to the ostia of Schlemm's canal via a window created at the corneal scleral bed without use of antimetabolites. Postoperative intraocular pressure (IOP), number of glaucoma medications, and procedure-related complications were evaluated. Success was defined as an IOP ≤21 mm Hg without (complete) or with (qualified) use of glaucoma medication.

RESULTS

Forty eyes in 40 patients with angle recession glaucoma underwent successful circumferential catheterisation. The mean patient age was 42±13 years. In patients with penetrating canaloplasty that was deemed to be completely successful, the mean IOP decreased from a preoperative value of 37.8±12.3 mm Hg on 3.3±1.2 anti-glaucoma medications to 18.5±6.4 mm Hg on 1.2±1.4 medications, 14.9±4.6 mm Hg on 0.1±0.5 medications, 15.7±5.4 mm Hg on 0.1±0.4 medications and 14.8±3.6 mm Hg on 0.1±0.5 medications at 1, 3, 6 and 12 months postoperatively (p<0.05). Complete success was achieved in 35/40 eyes (87.5%) at 6 months and in 34/38 (89.5%) at 12 months. Hyphema (18/40, 45.0%) and transient IOP elevation (≥30 mm Hg, 9/40, 22.5%) were the most common postoperative complications.

CONCLUSION

Penetrating canaloplasty significantly reduces IOP and has a high success rate in angle recession glaucoma.

TRIAL REGISTRATION NUMBER

ChiCTR1900020511.

Challenges in the complex management of post-keratoplasty glaucoma

Glaucoma is a serious complication after corneal transplantation and itself a common cause for graft failure and leading cause of vision loss post-keratoplasty due to corneal endothelial decompensation. Endothelial keratoplasty procedures like Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) may be superior to penetrating keratoplasty (PK) regarding the incidence of elevated intraocular pressure (IOP) and development of glaucoma. There are indications that regardless of the method of keratoplasty, some corneal diseases like pseudophakic bullous keratopathy, corneal perforation, and graft rejection have a higher risk for developing post-keratoplasty glaucoma than keratoconus and corneal dystrophies and likewise respond less to IOP lowering therapy. In this review, the pathophysiology of post-keratoplasty glaucoma, the diagnostic tools with focus on different devices, and their limitations with regard to measuring IOP and the treatment modalities are presented.

Canaloplasty in Pigmentary Glaucoma: Long-Term Outcomes and Proposal of a New Hypothesis on Its Intraocular Pressure Lowering Mechanism

This study presents the long-term results on canaloplasty in a group of patients affected by pigmentary glaucoma, and studies the progression of the disease after surgery. Material and methods: Twenty-nine eyes of 25 patients with pigmentary glaucoma in maximum tolerated medical therapy with significant visual field damage progression underwent canaloplasty and were followed up to 11 years (mean 59.8 ± 30.1 months). All patients underwent a complete ophthalmic examination every 6 months. Results: The pre-operative mean intraocular pressure (IOP) was 31.8 mmHg ± 10.9 (range 21–70) with an average of 3.3 medications. After 1, 2, 3, and 4 years, the mean IOP was 15.9 ± 4.0, 14.4 ± 7.3, 14.1 ± 2.1, and 15.7 mmHg, respectively, with 0.4, 0.5, and 0.7 medications, respectively. Four patients underwent trabeculectomy after 3 to 30 months due to uncontrolled IOP. Gonioscopy showed a significant reduction of pigment in trabecular meshwork in all cases, starting from the sixth month. In some cases, the pigment was almost completely reabsorbed after two years, suggesting an accelerated transit and escape of the granules through the trabecular spaces. Conclusions: Canaloplasty seems to be a reasonable option in treating patients affected by progressive pigmentary glaucoma. The reabsorption of pigment granules from the trabecular meshwork could, at least in part, explain the relatively high success rate observed after this surgical procedure.

Hemorrhagic Descemet's Membrane Detachment in Nonpenetrating Glaucoma Surgery

PURPOSE

To describe 5 representative cases of hemorrhagic Descemet's membrane (DM) detachment in glaucoma surgery that had different origins, mechanisms and treatments.

METHODS

Clinical records of patients that had undergone a nonpenetrating glaucoma surgery, with a diagnosis of hemorrhagic DM detachment were reviewed for demographic data, clinical findings and treatment applied.

RESULTS

Five patients with hemorrhagic DM detachment were included in this case series. They all had different causes, namely a massive hemorrhage at the end of a canaloplasty procedure, a needling maneuver, autologous blood injection, Swan syndrome, and frequent eye rubbing. Hematoma evacuation was performed in 4 eyes, 1 of them from under the scleral flap of the deep sclerectomy and 3 of them through a surgical or laser perforation in DM. Air tamponade was done in most of these cases. One of these cases required transcorneal suture fixation. One case was observed expectantly. All cases successfully recovered but peripheral corneal stain was persistent in 2 cases.

CONCLUSION

Hemorrhagic DM detachment is a rare but potential vision-threatening complication in glaucoma surgery. Different mechanisms may cause the bleeding and there are several techniques available to approach this complication. Pre-Descemet hematoma should be drained to avoid permanent corneal stain and air/gas tamponade may help to prevent recurrences.

Efficacy and Safety of Trabeculectomy Versus Nonpenetrating Surgeries in Open-angle Glaucoma: A Meta-analysis

PURPOSE

The purpose of this study was to conduct a meta-analysis on the efficacy and safety of trabeculectomy (TE) and nonpenetrating glaucoma surgery (NPGS) techniques in patients with primary open-angle glaucoma, pseudoexfoliation glaucoma, pigmentary glaucoma, and normal-tension glaucoma.

METHODS

All studies were identified by searching electronic sources (PubMed, Medline, Scopus, and Embase) until February 5, 2018. Primary outcome was mean intraocular pressure (IOP) reduction at 6, 12, and 24 months. Complications, number of antiglaucomatous medications, and visual outcomes were also evaluated.

RESULTS

Twenty-one studies were included. Ten studies compared TE with deep sclerectomy (DS), 5 with viscocanalostomy (VC), 1 study with both DS and VC, and 5 with canaloplasty (CP). TE was superior to DS, VC, and CP in reducing IOP at 6 and 12 months, and to DS at 24 months. When comparing TE to VC and to CP at 24 months, there was no significant difference in IOP reduction. Hypotony, choroidals, anterior chamber shallowing or flattening, and cataract formation or progression were more associated with TE than with NPGSs. TE was more effective in reducing antiglaucomatous medications than VC and CP.

CONCLUSIONS

TE is more effective in reducing IOP. TE presents a higher risk of complications as compared with NPGS, except for hyphema.

Estimation of risk-benefit ratio and comparison of post-operative efficacy results between trabeculectomy and canaloplasty

PURPOSE

To estimate a risk-benefit ratio by comparing the efficacy of canaloplasty to trabeculectomy exclusively in pseudophakic eyes with primary open angle glaucoma.

PATIENTS AND METHODS

One hundred four eyes that underwent ab externo canaloplasty and 136 eyes that underwent trabeculectomy with mitomycin C 0.02% and collagen matrix implantation were retrospectively compared. The efficacy was evaluated by evaluating the absolute success rate (5 ⩽ intraocular pressure ⩽ 15 mmHg) and the qualified success rate (intraocular pressure ⩽15 mmHg) using the Kaplan-Meier survival analysis. A meta-analysis to evaluate the relative risk of both procedures in relation to post-operative interventions was performed.

RESULTS

Mean intraocular pressure was significantly lower in both groups. Intraocular pressure decreased by 32.17% in the canaloplasty group and by 55.04% in the trabeculectomy group at 12 months (analysis of variance, p < 0.001). Medication use was lower in both groups (analysis of variance, p < 0.001) by the 12th month. The absolute success rate for canaloplasty was 20.19% of eyes compared to 52.21% of eyes with trabeculectomy (p < 0.0001). The qualified success rate was not statistically different between groups (p = 0.15). The relative risk ratio was not statistically different between groups (relative risk of 0.01 and weight of 49.65% for group A and relative risk of 0.0005 and weight of 50.35% for group B; p = 0.5). The hospitalization length was longer in trabeculectomy-treated patients (t-test, p < 0.0001).

CONCLUSION

The trabeculectomy group showed better results in terms of absolute success rate. However, canaloplasty may provide a better risk-benefit ratio in terms of qualified success rate, hospitalization time, and required post-operative interventions, since canaloplasty yielded equal or superior results compared to trabeculectomy.

C3 Transferase-Expressing scAAV2 Transduces Ocular Anterior Segment Tissues and Lowers Intraocular Pressure in Mouse and Monkey

Glaucoma is a lifelong disease with elevated intraocular pressure (IOP) as the main risk factor, and reduction of IOP remains the major treatment for this disease. However, current IOP-lowering therapies are far from being satisfactory. We have demonstrated that the lentivirus-mediated exoenzyme C3 transferase (C3) expression in rat and monkey eyes induced relatively long-term IOP reduction. We now show that intracameral injection of self-complementary AAV2 containing a C3 gene into mouse and monkey eyes resulted in morphological changes in trabecular meshwork and IOP reduction. The vector-transduced corneal endothelium and the C3 transgene expression, not vector itself, induced corneal edema as a result of actin-associated endothelial barrier disruption. There was a positive (quadratic) correlation between measured IOP and grade of corneal edema. This is the first report of using an AAV to transduce the trabecular meshwork of monkeys with a gene capable of altering cellular structure and physiology, indicating a potential gene therapy for glaucoma.

Open-Angle Glaucoma: Burden of Illness, Current Therapies, and the Management of Nocturnal IOP Variation

Glaucoma is a chronic, debilitating disease and a leading cause of global blindness. Despite treatment efforts, 10% of patients demonstrate loss of vision. In the US, > 80% of glaucoma cases are classified as open-angle glaucoma (OAG), with primary open-angle (POAG) being the most common. Although there has been tremendous innovation in the surgical treatment of glaucoma as of late, two clinical variants of OAG, normal-tension glaucoma (NTG) and severe POAG, are especially challenging for providers because patients with access to care and excellent treatment options may progress despite achieving a “target” intraocular pressure value. Additionally, recent research has highlighted the importance of nocturnal IOP control in avoiding glaucomatous disease progression. There remains an unmet need for new treatment options that can effectively treat NTG and severe POAG patients, irrespective of baseline IOP, while overcoming adherence limitations of current pharmacotherapies, demonstrating a robust safety profile, and more effectively controlling nocturnal IOP.

Funding The Rapid Service Fees were funded by the corresponding author, Tanner J. Ferguson, MD.

360° ab-interno trabeculotomy in refractory primary open-angle glaucoma

Purpose

The purpose of this study was to evaluate the safety and efficacy of microinvasive glaucoma surgery (MIGS) with 360° ab-interno trabeculotomy using the TRAB360 device as a stand-alone procedure in patients with refractory primary open-angle glaucoma (POAG) and preoperative IOP ≥18 mmHg.

Setting

This study evaluated patients treated in a tertiary-referral clinical practice setting.

Design

This study is a retrospective analysis of 81 eyes.

Methods

Patients with refractory open-angle glaucoma underwent stand-alone 360° ab-interno trabeculotomy using the TRAB360 device. Effectiveness was determined by reduction in medicated IOP and the use of medications from baseline. Safety was determined by the rate of adverse events and secondary surgical interventions. The time points assessed were baseline and postoperative day 1, week 1, and months 1, 3, 6, and 12. A subgroup analysis was performed on eyes with medicated preoperative IOP values of ≥25 mmHg.

Results

The reductions in IOP from 1 day to 12 months postoperatively were statistically significant compared to baseline values. The mean reduction in IOP at 12 months was 7.3±6.7 mmHg from baseline. At 12 months, 59% eyes achieved ≥20% reduction in IOP and IOP <18 mmHg with the same or fewer numbers of IOP-lowering medications compared with those at baseline. The mean number of IOP-lowering medications was reduced from 1.7±1.3 at baseline to 1.1±1.0 at 12 months. At 12 months, 67% of eyes with preoperative IOP values of ≥25 mmHg achieved ≥20% reduction in IOP and IOP <18 mmHg with the same or fewer numbers of IOP-lowering medications compared with those at baseline. The most common adverse event for all eyes was mild, transient hyphema (57 eyes). During the first year after the procedure, 20 (25%) eyes were considered failures since they required reinterventions.

Conclusion

Trabeculotomy using the TRAB360 device resulted in significant IOP reductions up to 1 year with a favorable safety profile. The device is an effective stand-alone MIGS procedure for patients with refractory POAG.

Canaloplasty in the Treatment of Open-Angle Glaucoma: A Review of Patient Selection and Outcomes

Canaloplasty is a relatively new non-penetrating surgery for the reduction of intraocular pressure in patients affected by glaucoma. The technique uses a microcatheter to perform a 360 º cannulation of Schlemm’s canal and leaves in place a tension suture providing an inward distension. It aims to restore the physiological outflow pathways of the aqueous humour and is independent of external wound healing. Several studies have shown that canaloplasty is effective in reducing intraocular pressure and has a low rate of complications, especially compared with trabeculectomy, the gold standard for glaucoma surgery. Currently, canaloplasty is indicated in patients with open-angle glaucoma, having a mild to moderate disease, and the combination with cataract phacoemulsification may provide further intraocular pressure reduction. This article reviews canaloplasty indications, results and complications and analyses its outcomes compared with traditional penetrating and non-penetrating techniques.

Ab interno canaloplasty for the treatment of glaucoma: a case series study

Purpose

To describe and evaluate the efficacy of ab interno canaloplasty (ABiC) in patients with primary open-angle glaucoma (POAG).

Methods

This single-center consecutive case series study included patients with cataract and open-angle glaucoma (combined procedure) and pseudophakic patients (mean age, 76 years; range, 66–83 years) with POAG who underwent ABiC using the iTrack™ 250-μm microcatheter (Ellex Medical Lasers Pty Ltd, Adelaide, Australia) to circumferentially viscodilate and intubate Schlemm’s canal without placement of a tensioning suture. The primary endpoints were mean intraocular pressure (IOP) and mean number of glaucoma medications at 1, 3, 6, 9, and 12 months postoperatively.

Results

In total, 20 patients (20 eyes) were enrolled in the study. Mean IOP reduced from 18.5 ± 3.44 mm Hg preoperatively to 14.88 ± 2.82 mm Hg (n = 17), 13.80 ± 2.05 (n = 12), 14.57 ± 2.59 mm Hg (n = 9) and 15.47 ± 2.42 (n = 6) at 1, 3, 6 and 9 months postoperatively. The 12‑month data for two patients showed that IOP had reduced from 17 mm Hg preoperatively to 16 mm Hg in one patient and from 20 mm Hg to 13 mm Hg in the other patient. The mean number of medications was reduced from 2.4 preoperatively to 0.25 at the last follow-up visit. There was one reported complication of limited descemetolysis near the limbus by the viscoelastic during the dilatation of Schlemm’s canal. No adverse events as a result of the device were reported.

Conclusions

ABiC was straightforward to perform in this group of patients with minimal complications. Although initial findings from this study indicate that ABiC is comparable to conventional canaloplasty in lowering IOP and medication dependency, long-term follow-up in a large patient cohort is required to confirm the efficacy of this minimally invasive glaucoma procedure.

Comparison of surgical outcomes between canaloplasty and trabeculectomy with mitomycin C at 2-year follow-up: A longitudinal cohort study

Purpose:

To compare operative outcomes of patients after canaloplasty and trabeculectomy with mitomycin C (MMC) through 2-year follow-up.

Methods:

We included 31 eyes of 31 patients with primary open-angle glaucoma (POAG) who underwent canaloplasty and 37 eyes of 37 patients with POAG who underwent trabeculectomy with MMC with 24 months of postoperative follow-up. All surgeries were performed by a single surgeon between January 2005 and May 2011. Failure was defined as intraocular pressure (IOP >18 or <4 mmHg at 2 years), second operative procedure, or loss of light perception. Change in IOP, visual acuity (VA), glaucoma medications, and complication rates at 24 months were analyzed.

Results:

Caucasians made up to half of the patients included in this study (58% vs. 43%) while the rest where either African Americans (32% vs. 43%) or Hispanic (10% vs. 14%) patients between the canaloplasty and trabeculectomy group. Both groups showed significant reduction in IOP from baseline at 24 months. Trabeculectomy patients had a greater mean reduction of IOP compared to canaloplasty patients (12.2 ± 12 vs. 4.7 ± 7.5, P = 0.003) and also achieved lower IOP at 24 months (12.2 ± 4.1 vs. 14.9 ± 6.0, P = 0.03). Postoperative glaucoma medication use was less in the trabeculectomy group (n = 0, interquartile range [IQR] 0–2) compared to those in whom canaloplasty was performed (n = 2, IQR 0–3, P = 0.02). VA showed no statistical change in either group over 2 years. Overall failure rates at 2 years were comparable between the two groups: 32% for trabeculectomy and 26% for canaloplasty (P = 0.6). Subgroup analysis revealed a lower failure rate in Caucasions (15%) when compared to Blacks (42%) and Hispanics/others (50%, P = 0.03).

Conclusion:

Canaloplasty and trabeculectomy both achieved significant reduction in IOP with comparable success rates. Trabeculectomy can achieve a greater reduction in IOP while requiring fewer medications however is associated with more intensive postoperative care and frequent interventions. Pigmented populations have worse outcomes compared to Caucasians.

A retrospective analysis of the use of loteprednol etabonate ophthalmic suspension 0.5% following canaloplasty

Background

While loteprednol etabonate (LE) suspension 0.5% is approved for the treatment of postoperative ocular inflammation, there have been no reported studies of its use in glaucoma patients undergoing canaloplasty.

Methods

This was a retrospective medical chart review conducted at a single US center. Data were collected on patients with glaucoma who underwent canaloplasty with or without cataract surgery, and were prescribed LE suspension 0.5% postoperatively. Outcomes evaluated included postsurgical inflammation (anterior chamber [AC] cells and flare), intraocular pressure (IOP), number of IOP-lowering medications, and postsurgical complications.

Results

Data were collected on 204 patients (262 eyes) with a mean (SD) age of 71.6 (11.3) years. The most frequent LE dosing regimens at day 1, week 1, and month 1 postsurgery were QID (92.3%; 241/261), TID (52.6%; 133/253), and QD (65.5%; 78/119), respectively. Inflammation (AC flare and cells), mostly mild, was noted in 33.2% (86/259) of eyes on postoperative day 1 and 8.6% (21/244) of eyes at month 1. Mean IOP and mean number of IOP-lowering medications were significantly reduced from baseline (P<0.001) at all time points postoperatively. Complete (no IOP-lowering medication) or qualified (use of ≤2 IOP-lowering medications) surgical success was achieved in 78.8% and 90.6% of eyes, respectively, at month 6 and 63.4% and 92.7% of eyes at month 36. The most frequently observed postoperative complication was hyphema in 48.7% (126/259) eyes at day 1, which decreased to 0.4% (1/244) of eyes by month 1. IOP ≥30 mmHg was noted in 13 (5.3%) eyes at postoperative week 1 and rarely thereafter, and no patient discontinued therapy because of an IOP increase.

Conclusion

These real-world data suggest that canaloplasty with or without cataract surgery managed postoperatively with LE suspension 0.5% is effective and safe in the glaucoma patient.

Strategies to Reduce Oxidative Stress in Glaucoma Patients

BACKGROUND

Primary open-angle glaucoma (POAG) is a multifactorial pathology involving a variety of pathogenic mechanisms, including oxidative/nitrosative stress. This latter is the consequence of the imbalance between excessive formation and insufficient protection against reactive oxygen/nitrogen species.

OBJECTIVE

Our main goal is to gather molecular information to better managing pathologic variants that may determine the individual susceptibility to oxidative/nitrosative stress (OS/NS) and POAG.

METHOD

An extensive search of the scientific literature was conducted using PUBMED, the Web of Science, the Cochrane Library, and other references on the topic of POAG and OS/NS from human and animal model studies published between 2010 and 2017. Finally, 152 works containing relevant information that may help understanding the role of antioxidants, essential fatty acids, natural compounds and other similar strategies for counteracting OS/NS in POAG were considered.

RESULTS

A wide variety of studies have proven that antioxidants, among them vitamins B3, C and E, Coenzyme Q10 or melatonin, ω-3/ω-6 fatty acids and other natural compounds (such as coffee, green tea, bear bile, gingko biloba, coleus, tropical fruits, etc.,) may help regulating the intraocular pressure as well as protecting the retinal neurons against OS/NS in POAG.

CONCLUSION

Based on the impact of antioxidants and ω-3/ω-6 fatty acids at the molecular level in the glaucomatous anterior and posterior eye segments, further studies are needed by integrating all issues involved in glaucoma pathogenesis, endogenous and exogenous risk factors and their interactions that will allow us to reach newer effective biotherapies for preventing glaucomatous irreversible blindness.

Glaucoma

Glaucoma is a heterogeneous group of diseases characterised by cupping of the optic nerve head and visual-field damage. It is the most frequent cause of irreversible blindness worldwide. Progression usually stops if the intraocular pressure is lowered by 30-50% from baseline. Its worldwide age-standardised prevalence in the population aged 40 years or older is about 3·5%. Chronic forms of glaucoma are painless and symptomatic visual-field defects occur late. Early detection by ophthalmological examination is mandatory. Risk factors for primary open-angle glaucoma-the most common form of glaucoma-include older age, elevated intraocular pressure, sub-Saharan African ethnic origin, positive family history, and high myopia. Older age, hyperopia, and east Asian ethnic origin are the main risk factors for primary angle-closure glaucoma. Glaucoma is diagnosed using ophthalmoscopy, tonometry, and perimetry. Treatment to lower intraocular pressure is based on topical drugs, laser therapy, and surgical intervention if other therapeutic modalities fail to prevent progression.

Clinical evaluation of aqueous outflow system in vivo and correlation with intraocular pressure before and after non-penetrating glaucoma 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.

Safety and efficacy of canaloplasty versus trabeculectomy in treatment of glaucoma

We assess 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 potentially 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 postoperative 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.

A System Review and Meta-Analysis of Canaloplasty Outcomes in Glaucoma Treatment in Comparison with Trabeculectomy

Purpose. This system review studied the efficiency and safety of canaloplasty (CP) and compared the outcomes between CP and trabeculectomy (TE). Methods. Literatures were searched in PubMed and EMBASE. The meta-analysis was conducted on the postoperative outcomes in CP and then on the differences of outcomes between CP and TE. Results. In the meta-analysis, IOP decreased by 9.94 (95% CI 8.42 to 11.45) mmHg with an average AGM reduction of 2.11 (95% CI 1.80 to 2.42) one year after CP. The IOP reduction was significantly higher after TE than after CP, with an average difference of 3.61 (95% CI 1.69 to 5.53) mmHg at 12 months postoperationally. For complications, the incidence of hyphema was significantly higher in CP 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 and of choroidal effusion/detachment. Meanwhile, suprachoroidal hemorrhage and bleb needling were only reported in TE. 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. More high-quality researches are needed in the future to verify our findings in this system review.

Canaloplasty versus Viscocanalostomy in Primary Open Angle Glaucoma

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.

[Comparison of trabeculectomy and canaloplasty : Pressure reducing effect and postoperative interventions/complications]

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.

Comparison of canaloplasty and trabeculectomy for open angle glaucoma: a Meta-analysis

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.

Incidence and management of haemorrhagic Descemet membrane detachment in canaloplasty and phacocanaloplasty

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.

CONCLUSION

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.

Evaluation of Outflow Structures In Vivo after the Phacocanaloplasty

Purpose. To evaluate the in vivo changes in 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 and 3 women) 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 versus 5098.8 (1190.5) μm², p < 0.001) and a decrease in mean TM thickness (91.2 (18.6) μm versus 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) and 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.

[Revision procedures after canaloplasty]

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: Current Value in the Management of Glaucoma

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.

Ocular Decompression Retinopathy Following Canaloplasty for Primary Open Angle Glaucoma: A Case Report

Ocular decompression retinopathy (ODR), a rare postoperative complication following glaucoma surgery, is characterized by the transient appearance of scattered retinal hemorrhages. Here, we present a unique case of ODR in a patient with primary open angle glaucoma who underwent canaloplasty. A 31-year-old male patient presented with an intraocular pressure (IOP) of 60 mm Hg in the right eye. The IOP remained over 40 mm Hg, even when treated with maximum tolerated antiglaucoma medication. Canaloplasty drastically lowered IOP in the right eye from 40 to 7 mm Hg. However, fundus examination revealed ODR after surgery. The patient was treated with tobramycin and dexamethasone. Three months after canaloplasty, IOP remained in control at 16 mm Hg and all retinal hemorrhages had completely resolved. This case demonstrates that ODR can occur following canaloplasty and physicians should be aware of this potential complication in patients with severely elevated IOP. Sufficiently lowering IOP before surgery and gradually decreasing IOP during surgery may prevent ODR from occurring.

Comparison of Surgical Outcomes between Canaloplasty and Schlemm's Canal Scaffold at 24 Months' Follow-Up

The results of canaloplasty (CP) and Hydrus Microstent (HM) implantation were retrospectively compared at 24 months' follow-up in a cohort of subjects referred to our Institution for uncontrolled IOP in primary or secondary (e.g., pseudoexfoliative and pigmentary) open-angle glaucoma. The outcome was labelled as “complete” success, “qualified” success, or “failure” if, two years after surgery, the eyes operated on needed “no” hypotensive medications, “some” hypotensive medications, or further glaucoma surgery to attain the target IOP, respectively. Both CP and HM implant allowed significant IOP reductions, with comparable rate of clinical success and safety profile. A slightly (albeit not significant) better trend for a “complete” clinical success was observed in the CP group.

Comparison of 1-Site and 2-Site Phacotrabeculectomy in the Small Adult Eyes With Concomitant Cataract and Glaucoma

The aim of this study was to compare the outcomes after phacotrabeculectomy at 1 or 2 sites in the small adult eyes with concomitant cataract and glaucoma.Patients who had 1-site (n = 26) or 2-site (n = 14) phacotrabeculectomy over a 4-year period at an eye surgery center were included. Eighteen eyes of 18 patients with glaucoma using any 1 prostaglandin analogue (latanoprost, travoprost, or bimatoprost) were compared with 8 normal control patients. The records of patients were reviewed, and intraocular pressure, best-corrected visual acuity, axial length, anterior chamber depth, corneal endothelial cell (CEC) density, Diopter were measured. The outcome was compared with postoperative and preoperative measurements for 3-month follow-ups.The follow-up time was 3 months. There was no difference between the operations in improving best-corrected visual acuity, lowering intraocular pressure, shortening axial length, and deepening anterior chamber depth. However, 2-site surgery was associated with significantly more CEC loss and refractive error. Postoperative complications were not different between the 2 groups.The CEC loss and the refractive error in 2-site group were higher than that of 1-site group. One-site surgery seems to cause less CEC damage and refractive error than the 2-site operation during the follow-up time of 3 months.