Treatment outcomes in the Tube Versus Trabeculectomy (TVT) study after five years of follow-up

Techniques and Preferences for Nonvalved Aqueous Shunts: A Survey of American Glaucoma Society Members

PURPOSE

To assess practice patterns and opinions of glaucoma specialists regarding indications, surgical technique, and postoperative management for nonvalved aqueous shunts.

DESIGN

Anonymous online survey study.

PARTICIPANTS

American Glaucoma Society (AGS) members.

METHODS

An anonymous online survey was distributed to glaucoma specialists via the AGS forum from June to August 2022.

MAIN OUTCOME MEASURES

Survey questions and responses were assessed in 4 sections: (1) general demographics and practice patterns; (2) nonvalved tubes vs. trabeculectomy; (3) nonvalved tubes vs. valved tubes; and (4) nonvalved tube techniques.

RESULTS

There were 132 respondents; nonvalved tubes were reported to be performed more often than trabeculectomy by 61% of respondents within 5 years of completing training and 23% of respondents with more than 15 years since completing training. The most frequently preferred types of nonvalved tubes were Baerveldt-350 (41%), Baerveldt-250 (27%), and ClearPath-250 (18%). In patients with lower target intraocular pressure (IOP), 92% of respondents preferred trabeculectomy over nonvalved tube; 33% cited a cutoff of < 12 mmHg, and 31% cited a cutoff of < 15 mmHg. In patients with higher preoperative IOP, 50% of respondents preferred valved over nonvalved tubes; 29% cited a cutoff of > 40 mmHg, and 38% cited a cutoff of > 30 mmHg. The most frequently used ligature was 7-0 Vicryl (69%). The most frequently used strategies for early IOP lowering were fenestrations without wicks (70%) and with wicks (22%), with one 10-0 Nylon being the most used wick technique (22%). Overall, 37% of respondents use a ripcord; among ripcord users, 55% use it for hypotony prevention (3-0 Prolene most common for this purpose at 35%), and 40% use it for optional early IOP lowering (4-0 Nylon most common for this purpose at 21%). If IOP is too high at postoperative week 4, 38% of respondents do not open the tube early.

CONCLUSIONS

We demonstrate significant heterogeneity regarding specific indications, surgical technique, and postoperative management for nonvalved tubes. Future work is needed to identify and develop standardized guidelines alongside best practices.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Difficult decisions, filtration surgery, and the heartbreak of the numerator

A 70-year-old man had progressive and severe glaucoma in each eye. He was intolerant to dorzolamide, brimonidine, and netarsudil. Each eye had prior selective laser trabeculoplasty (SLT) as well as phacoemulsification plus minimally invasive glaucoma surgery (MIGS) 6 years before current presentation (iStent [Glaukos Corp.] in the right eye and Cypass [Alcon Laboratories, Inc.] in the left eye). Postoperative acuities were 20/20 and 20/25 in the right and left eyes, respectively. When his left eye progressed with loss of central acuity despite peak intraocular pressures (IOPs) in the middle to upper teens, neuro-ophthalmology consultation was obtained (Figure 1JOURNAL/jcrs/04.03/02158034-202401000-00017/figure1/v/2023-12-22T124801Z/r/image-tiff). That workup included magnetic resonance imaging scan and hematologic screening, but all results were negative, and the neuro-ophthalmic consultant concluded that the vision loss was likely on the basis of glaucoma. Accordingly, a trabeculectomy was performed in the left eye achieving consistent IOPs in the range of 7 to 10 mm Hg without medications, rending the left eye stable since the filtration surgery nearly 2 years previously. The right eye continued to progress both subjectively and objectively, and on recent examination, the IOP measured 20 mm Hg and 09 mm Hg in the right and left eyes, respectively (Figure 2JOURNAL/jcrs/04.03/02158034-202401000-00017/figure2/v/2023-12-22T124801Z/r/image-tiff). Medications included timolol and latanoprostene bunod in the right eye only. Central corneal thickness was 526 μm and 527 μm in the right and left eyes, respectively. The visual acuity now measured 20/25 in the right eye and 20/250 in the left eye. The vertical cup-to-disc ratio was 0.9 in the right eye and 1.0 in the left eye. Gonioscopy revealed a wide open angle in each eye with a patent sclerostomy superiorly in the left eye. The conjunctiva and sclera were healthy and without scarring in the right eye. The bleb in the left eye was diffuse, lightly vascularized, and seidel negative. Axial length (AL) was 26.88 μm in the right eye and 26.77 μm in the left eye. The patient was in good health and was not anticoagulated. An extensive discussion ensued about the best course of action for the right eye. How would you proceed in managing definite progression in this individual's right eye, knowing that he had lost fixation in his left eye at similar pressures?

Full Thickness Prophylactic Scleral Windows Decrease the Rate of Choroidal Effusion and Drainage Surgery after Ahmed Glaucoma Valve Implantation

Purpose

To evaluate the effect of creating a full-thickness prophylactic scleral window (PSW) during Ahmed glaucoma valve (AGV) surgery on the rate of postoperative choroidal effusion and choroidal drainage surgery.

Methods

In this retrospective matched case-control study, after insertion of AGV tube a PSW was created in one group. The control-matched group had AGV without a PSW. Primary outcome measures were the rate of choroidal effusion formation and choroidal drainage surgery.

Results

In total, 544 patients (604 eyes) had undergone AGV implantation from 2013 to 2017. The PSW group consisted of 111 eyes of 111 patients and the control group had 111 eyes of 98 matched patients. There were no differences for systemic diseases, number of anti-glaucoma drugs, aspirin use, smoking, laterality of the operated eye, axial length, and central corneal thickness between the groups. Out of 12 eyes with choroidal effusion, only one belonged to the PSW group (P=0.02). Six eyes in the control group needed choroidal drainage surgery, but none of the eyes in the PSW group required this procedure (P=0.02). No intra- and postoperative issues were observed at the site of the scleral window in the PSW group.

Conclusion

PSW creation during AGV surgery is a safe method to decrease the rate of choroidal effusion and choroidal drainage surgery.

Phacogoniotomy versus phacotrabeculectomy for advanced primary angle-closure glaucoma with cataract: A randomized non-inferiority trial

PURPOSE

To investigate the effectiveness and safety of phacogoniotomy versus phacotrabeculectomy (PVP) among patients with advanced primary angle-closure glaucoma (PACG) and cataracts.

DESIGN

Multicenter, randomized controlled, non-inferiority trial.

METHODS

A total of 124 patients (124 eyes) with advanced PACG and cataracts were enrolled, with 65 in the phacogoniotomy group and 59 in the phacotrabeculectomy group. Patients were followed up for 12 months with standardized evaluations. The primary outcome was the reduction in intraocular pressure (IOP) from baseline to 12 months postoperatively, of which a non-inferiority margin of 4 mmHg was evaluated. Secondary outcomes included the cumulative surgical success rate, postoperative complications, and changes in the number of glaucoma medications.

RESULTS

After 12 months, phacogoniotomy demonstrated non-inferiority to phacotrabeculectomy in terms of IOP reduction, with mean IOP reductions of - 26.1 mmHg and - 25.7 mmHg (P = 0.383), respectively, from baseline values of around 40 mmHg. Both groups experienced a significant reduction in the mean number of medications used postoperatively (P < 0.001). The cumulative success rate was comparable between the groups (P = 0.890). However, phacogoniotomy had a lower rate of postoperative complications and interventions (12.3% and 4.6%) compared to phacotrabeculectomy (23.7% and 20.3% respectively). The phacogoniotomy group reported shorter surgery time (22.1 ± 6.5 vs. 38.8 ± 11.1 min; P = 0.030) and higher quality of life (EQ-5D-5 L) improvement at 12 months (7.0 ± 11.5 vs. 3.0 ± 12.9, P = 0.010) than the phacotrabeculectomy group.

CONCLUSIONS

Phacogoniotomy was non-inferior to phacotrabeculectomy in terms of IOP reduction for advanced PACG and cataracts. Additionally, phacogoniotomy provided a shorter surgical time, lower postoperative complication rate, fewer postoperative interventions, and better postoperative quality of life.

Short-Term Outcomes of XEN45 Standalone versus Combined with Phacoemulsification in Open-Angle Glaucoma Patients: A Retrospective Study

The XEN45 is a minimally invasive glaucoma surgery device commonly used in clinical practice. This retrospective study included consecutive patients with open-angle glaucoma who underwent a XEN45 implant with mitomycin C, either alone or in combination with phacoemulsification, between June 2015 and March 2021. The primary end point was the mean change in intraocular pressure (IOP) from the baseline to month 6. A total of 677 eyes, 395 (58.3%) in the XEN alone group and 282 (41.7%) in the XEN+Phaco group, were included in this study. The preoperative IOP was significantly lowered from 28.7 ± 8.6 mmHg and 25.4 ± 6.9 mmHg to 13.5 ± 5.0 mmHg and 13.5 ± 4.1 mmHg at month 6 in the XEN solo and XEN+Phaco groups, respectively, with p < 0.0001 each. The mean (95% confidence interval) number of ocular hypotensive medications was significantly reduced from 3.3 (3.2-3.4) to 0.2 (0.1-0.2) and from 3.1 (2.9-3.2) to 0.2 (0.1-0.2) in the XEN solo and XEN+Phaco groups, respectively, with p < 0.0001 each. Needling was performed in 228 (33.7%) eyes. Conclusions: the XEN implant significantly reduces both IOP and the number of ocular hypotensive medications. IOP lowering was higher in the XEN solo group than in the XEN+Phaco one, although such a difference was only evident during the first month after surgery.

Alternatives to Topical Glaucoma Medication for Glaucoma Management

Topical glaucoma medications have favorable safety and efficacy, but their use is limited by factors such as side effects, nonadherence, costs, ocular surface disease, intraocular pressure fluctuations, diminished quality of life, and the inherent difficulty of penetrating the corneal surface. Although traditionally these limitations have been accepted as an inevitable part of glaucoma treatment, a rapidly-evolving arena of minimally invasive surgical and laser interventions has initiated the beginnings of a reevaluation of the glaucoma treatment paradigm. This reevaluation encompasses an overall shift away from the reactive, topical-medication-first default and a shift toward earlier intervention with laser or surgical therapies such as selective laser trabeculoplasty, sustained-release drug delivery, and micro-invasive glaucoma surgery. Aside from favorable safety, these interventions may have clinically important attributes such as consistent IOP control, cost-effectiveness, independence from patient adherence, prevention of disease progression, and improved quality of life.

The effects of the first versus second glaucoma drainage implant surgery in patients with primary open-angle glaucoma

BACKGROUND

To investigate the outcome of non-valved glaucoma drainage implant surgery (GDIS) in primary open-angle glaucoma (POAG) patients divided in the first GDI group (patients who underwent the first GDIS) and the second GDI group (patients who underwent the second GDIS because of the failed first GDIS).

METHODS

Intraocular pressure (IOP), visual acuity (VA), visual field defect (VFD), medication score (MS), survival rate of GDIS, complications, and patient background was retrospectively analyzed. Two success criteria were set: Criteria (1) IOP reduction ≥ 20% and 5 < IOP ≤ 21, Criteria (2) IOP reduction ≥ 20% and 5 < IOP ≤ 14.

RESULTS

There were 136 eyes of 109 patients in the first GDI group and 32 eyes of 27 patients in the second GDI group. In the first GDI group and II, mean preoperative IOP was 26.7 ± 6.7 mmHg and 23.7 ± 3.5 mmHg, respectively (P = 0.09). No statistically significant difference in postoperative IOP reduction was found between the two groups (P = 0.39). At 5-years postoperative, the Criteria 1 (Criteria 2) survival rate in the first GDI group and the second GDI group was 60.4% (31.7%) and 61.2% (25.6%), respectively (Criteria 1: hazard ratio [HR]: 0.64, 95% confidence interval [CI]: 0.30-1.35 [P = 0.24]; Criteria 2: HR: 0.81, 95% CI: 0.46-1.44, P = 0.48). No significant difference in VA, VFD change, MS, or complications was observed. Young patient age was the only significant factor for failure in the first GDI group (odds ratio: 0.95, 95% confidence interval: 0.91-1.00, P = 0.03).

CONCLUSION

The second GDIS may be as effective as the first GDIS for IOP reduction in POAG patients, however, there is a high risk of failure in young-age patients and the surgery may be ineffective in eyes requiring Criteria 2.

Tube Versus Trabeculectomy IRIS Registry Study: 1-Year Secondary Treatment Outcomes

PURPOSE

To describe 1-year secondary outcomes in the Tube Versus Trabeculectomy IRIS® (Intelligent Registry In Sight) Registry Study (TVTIRIS), and to compare to the TVT randomized controlled trial (TVTRCT).

DESIGN

TVTIRIS was a retrospective cohort study.

METHODS

The 2013-2017 IRIS Registry was used to identify eyes that received a tube shunt (tube) or trabeculectomy after a previous trabeculectomy and/or cataract surgery and had 1 year of follow-up. The TVTRCT compared a Baerveldt 350-mm2 glaucoma implant to trabeculectomy in similar eyes.

RESULTS

In the TVTIRIS cohort, the tube (n = 236, 56.3%) and trabeculectomy (n = 183, 43.7%) groups had similar and significant reductions in intraocular pressure (IOP) from baseline to 1 year. In the tube group, IOP (mean ± SD) decreased from 26.6 ± 6.5 mm Hg at baseline to 14.3 ± 4.8 mm Hg at 1 year. In the trabeculectomy group, IOP decreased from 25.3 ± 6.4 mm Hg at baseline to 13.5 ± 5.2 mm Hg at 1 year. The trabeculectomy groups from both studies had similar 1-year IOP reduction (P = .18), although the TVTRCT cohort used fewer medications at all time points (P < .01). There were more pronounced differences in the mean IOP and medications between the tube groups in the 2 studies, presumably due to the inclusion of valved tubes in TVTIRIS. More reoperations occurred in TVTIRIS.

CONCLUSIONS

The TVTIRIS tube and trabeculectomy groups had comparable 1-year IOP reduction, although trabeculectomy eyes used fewer glaucoma medications. The trabeculectomy group in TVTIRIS and TVTRCT had similar IOP and medication reduction at 1 year. Randomized controlled trials and electronic health record data both provide invaluable insight into surgical outcomes.

Comparative Effectiveness and Safety of Two Different Trabecular MIGS Devices With and Without Ab Interno Canaloplasty in Patients with Primary Open-Angle Glaucoma

INTRODUCTION

This study compared outcomes of the iStent inject trabecular micro-bypass system versus the Hydrus Microstent in patients with primary open-angle glaucoma (POAG).

METHODS

Forty subjects (80 eyes) with POAG were included in this single-center, retrospective, contralateral-eye analysis. All patients underwent phacoemulsification with either iStent inject or Hydrus implantation in one eye and the other device in the contralateral eye, with ≥ 3-month follow-up. In 58 eyes (27 iStent inject, 31 Hydrus) the surgery also included ab interno canaloplasty (ABiC). Twelve-month outcomes included intraocular pressure (IOP), medications, and adverse events. Subgroup analyses were completed for iStent inject versus Hydrus, and with versus without ABiC.

RESULTS

At 12 months versus baseline, mean IOP reduced from 16.8 ± 3.7 to 13.6 ± 2.9 (p = 0.003) in iStent inject eyes, and from 18.1 ± 4.5 to 14.9 ± 3.2 mmHg (p = 0.003) in Hydrus eyes (between-group IOP reduction p = 0.582). Mean number of glaucoma medications reduced from 1.23 ± 0.97 to 0.30 ± 0.76 (p < 0.001) in iStent inject eyes and from 1.20 ± 1.02 to 0.39 ± 0.72 (p = 0.001) in Hydrus eyes (between-group medication reduction p = 0.943). At 12 months, 82.6% of iStent inject eyes and 73.9% of Hydrus eyes were medication-free versus 20.0% preoperatively in both groups (p < 0.0001 both groups). There were no statistically significant IOP or medication differences between iStent inject and Hydrus pre- or postoperatively, both in the overall cohort and in the with/without ABiC subgroups. Outcomes also were similar between eyes with/without ABiC in the overall cohort and in the iStent inject/Hydrus subgroups. There were no adverse events in the iStent inject group; two eyes in the Hydrus group had device-related complications requiring five additional surgeries (one Hydrus repositioning, one Hydrus exchange, one Hydrus removal, two goniotomies).

CONCLUSION

In this contralateral-eye comparison of iStent inject versus Hydrus, the groups had similar IOP and medication outcomes, regardless of stratification by ABiC completion. Eyes receiving Hydrus had more complications and subsequent surgeries.

Risk Factors for Flat Anterior Chamber Requiring Intervention After Glaucoma Drainage Implant: A Retrospective Case-Controlled Study

PURPOSE

To identify risk factors for flat anterior chamber that required additional intervention in the postoperative period (90 days) after uncomplicated Baerveldt Glaucoma Implant (BGI) surgery.

DESIGN

Retrospective, matched case-control study.

METHODS

A total of 42 cases (eyes) that received BGI at Anne Bates Leach Eye Hospital between February 1, 2011, and January 1, 2019, and that developed flat anterior chamber were included. For each case, we matched 2 controls (84). Variables included sex, diagnosis, diabetes, hypertension, pre- and postoperative glaucoma medications, ocular conditions, and intraocular pressure (IOP). Multivariable conditional logistic regression determined odds ratios (ORs) for independent predictors.

RESULTS

Case patients were more likely to be female (69.1% case patients/41.7% controls), to have a history of taking oral carbonic anhydrase inhibitors (CAIs) at tube opening (21.4%/7.1%), to be of another race/ethnicity (11.9%/0.0%), and to have pseudoexfoliation (23.8%/6.0%), and were less likely to be using cholinergic agonists (0.0%/11.9%) at baseline and to have primary open angle glaucoma (42.9%/64.3%). Case patients had greater mean age (75.9/64.9 years), earlier tube opening time (5.6/6.2 weeks), and lower IOP after tube opening (7.2/14.4 mm Hg), but IOP before opening was higher (24.7/19.5 mm Hg). We identified 3 independent predictors: older age (10-year increase OR = 3.59, P < .0001), oral CAI use at tube opening (OR = 5.65, P = .009), and higher IOP prior to tube opening (3 mm Hg increase OR = 1.30, P = .018).

CONCLUSION

Risk factors for flat anterior chamber were older age, oral CAIs at tube opening, and higher IOP before tube opening. Strategies to minimize the acute IOP reduction that preceded this complication such as discontinuing oral CAI prior to tube opening may be considered.

Glaucoma: now and beyond

The glaucomas are a group of conditions leading to irreversible sight loss and characterised by progressive loss of retinal ganglion cells. Although not always elevated, intraocular pressure is the only modifiable risk factor demonstrated by large clinical trials. It remains the leading cause of irreversible blindness, but timely treatment to lower intraocular pressure is effective at slowing the rate of vision loss from glaucoma. Methods for lowering intraocular pressure include laser treatments, topical medications, and surgery. Although modern surgical innovations aim to be less invasive, many have been introduced with little supporting evidence from randomised controlled trials. Many cases remain undiagnosed until the advanced stages of disease due to the limitations of screening and poor access to opportunistic case finding. Future research aims to generate evidence for intraocular pressure-independent neuroprotective treatments, personalised treatment through genetic risk profiling, and exploration of potential advanced cellular and gene therapies.

Microfluidics in the eye: a review of glaucoma implants from an engineering perspective

Glaucoma is a progressive optic neuropathy in the eye, which is a leading cause of irreversible blindness worldwide and currently affects over 70 million individuals. Clinically, intraocular pressure (IOP) reduction is the only proven treatment to halt the progression of glaucoma. Microfluidic devices such as glaucoma drainage devices (GDDs) and minimally invasive glaucoma surgery (MIGS) devices are routinely used by ophthalmologists to manage elevated IOP, by creating an artificial pathway for the over-accumulated aqueous humor (AH) in a glaucomatous eye, when the natural pathways are severely blocked. Herein, a detailed modelling and analysis of both the natural microfluidic pathways of the AH in the eye and artificial microfluidic pathways formed additionally by the various glaucoma implants are conducted to provide an insight into the causes of the IOP abnormality and the improvement schemes of current implant designs. The mechanisms of representative glaucoma implants have been critically reviewed from the perspective of microfluidics, and we have categorized the current implants into four groups according to the targeted drainage sites of the AH, namely Schlemm's canal, suprachoroidal space, subconjunctival space, and ocular surface. In addition, we propose to divide the development and evolution of glaucoma implant designs into three technological waves, which include microtube (1st), microvalve (2nd) and microsystem (3rd). With the emerging trends of minimal invasiveness and artificial intelligence in the development of medical implants, we envision that a comprehensive glaucoma treatment microsystem is on the horizon, which is featured with active and wireless control of IOP, real-time continuous monitoring of IOP and aqueous rate, etc. The current review could potentially cast light on the unmatched needs, challenges, and future directions of the microfluidic structural and functional designs of glaucoma implants, which would enable an enhanced safety profile, reduced complications, increased efficacy of lowering IOP and reduced IOP fluctuations, closed-loop and on-demand control of IOP, etc.

Minimally Invasive Glaucoma Surgery: Latest Developments and Future Challenges

The development of minimally invasive glaucoma surgeries (MIGSs) was intended to provide safe and modestly efficacious modalities for early intervention of mild-to-moderate glaucoma, with minimal trauma and rapid recovery. They were mainly ab interno procedures that reduce intraocular pressure by facilitating the aqueous outflow by bypassing the trabecular meshwork resistance, reinforcing the uveoscleral flow via the supraciliary space, and reducing aqueous production by the ciliary body. While the cumulating evidence helps shape the role of the available MIGS, the exponential new development and advancement in this field has expanded the territory of MIGS. Apart from developing subconjunctival MIGS filtration devices (Xen gel stent and PRESERFLO MicroShunt), there is a tendency to revisit the "traditional" MIGS for alternative use and to modify the procedures with consideration of the fundamental aqueous outflow physiology. Combined MIGS has also been suggested, based on the theory that their different mechanisms may provide additive or synergistic effects. The advancement of laser procedures is also promising and could supplement unmet needs along the glaucoma treatment algorithm. This review examines the broad array of MIGS, updates the recent findings, discusses their potential alternative applications, and explores future challenges.

Glaucoma Fellows-in-Training Recent Surgery Trends

PURPOSE

The volume of microinvasive glaucoma surgery (MIGS) has increased dramatically in recent years, from 31 059 in 2013 to 69 420 in 2018. We investigated the impact of this trend on trainees by determining the proportion of glaucoma surgeries performed by fellows-in-training comprised by MIGS, trabeculectomies, and aqueous shunts.

DESIGN

Retrospective analysis.

PARTICIPANTS

Fellows-in-training at Glaucoma Fellowship Programs certified by the Association of University Professors of Ophthalmology Fellowship Compliance Committee (AUPO-FCC) METHODS: We analyzed aggregate summaries of surgeries performed by fellows as reported to the AUPO-FCC from the academic years (AYs) beginning in 2014 through AY 2020. Each report lists the average number of procedures performed per surgery type per fellow. We combined these averages to create a sum "average number surgeries performed" across glaucoma surgeries and computed the proportion that each surgery type (MIGS, trabeculectomies, and aqueous shunts) represented within the total average number of surgeries performed per year.

MAIN OUTCOME MEASURES

Average number of procedures performed for each surgery type as well as the proportion that each surgery type (MIGS, trabeculectomies, and aqueous shunts) represented within the total average number of procedures performed per year.

RESULTS

Average number of MIGS performed is significantly greater in later years compared with earlier years (P < 0.001). The average number of trabeculectomies performed between AYs 2014 and AY 2020 ranged from 21.8 to 31.9 and decreased, on average, by - 0.80 year-to-year. The average number of aqueous shunts performed between AY 2014 and AY 2020 ranged from 44.7 to 49.5, with an average increase of + 0.8 year-to-year. The total average number of procedures performed (across all 3 surgical subtypes) increased on average by + 4.8 procedures each year.

CONCLUSIONS

Since 2014, fellows are performing increasing numbers of MIGS procedures, whereas the total number of trabeculectomies and aqueous shunt surgeries performed each year remain similar, resulting in a net increase in total number of procedures performed per fellow each year. This suggests the increase in MIGS is not associated with a substantial decline in trabeculectomies or aqueous shunts performed by glaucoma fellows.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Results of a modified ab-external trabeculectomy surgical technique in patients with open angle glaucoma

OBJECTIVE

Assess the safety and efficacy of a Modified Ab-externo Trabeculectomy surgical technique in controlling intraocular pressure (IOP) in open-angle glaucoma patients.

METHODS AND ANALYSIS

Patients diagnosed with primary or secondary open-angle glaucoma underwent this modified technique as the first filtering surgical treatment were included. The preoperative and final follow-up assessed IOP, hypotensive medications, the need for additional treatments, and early and late complications.

RESULTS

Forty-eight eyes of 38 patients were included. The mean age was 63.1 years (25-85 years), and the mean follow-up time was 35.3 months (range of 1147 months). The mean preoperative IOP was 25.21±3.48mmHg and 15.83±4.4mmHg by the follow-up end. Subsequent laser goniopuncture was performed on 14 eyes (29%) and needling in 4 eyes (8.4%). Complete success was achieved in 18 eyes (37.5%), qualified success in 17 (35.4%), and failed in 13 eyes (27.1%). Kaplan-Meier survival analysis shows a success rate of 81.7% at two years and 54.9% from year 4 to year 12. Multivariate analysis with generalized estimating equations (GEE) shows younger age as the main predictor for failure. Two eyes had choroidal detachment, three eyes progressed to cataracts that needed surgery, and five eyes had early bleb leaks.

CONCLUSIONS

This proposed technique is an effective surgical procedure for treating open-angle glaucoma with effective long-term IOP control and a low incidence of surgical complications and could be used in selected complex cases based on these results.

One-Year Outcomes of Ab Externo XEN45 Gel Stent Implantation with an Open Conjunctiva Approach in Patients with Open-Angle Glaucoma

PURPOSE

This study aimed to evaluate the 1-year surgical outcomes of XEN45 gel stent implantation with an open conjunctiva approach in patients with open-angle glaucoma (OAG).

METHODS

This retrospective cohort study included 19 eyes of 19 patients who underwent XEN45 gel stent implantation with an open conjunctival approach. Surgical success was defined by intraocular pressure (IOP) ≤18 mmHg and one of the following: IOP reduction ≥30% or reduction of two glaucoma medications with final IOP if baseline IOP ≤18 mmHg. The cumulative probability of success rate was analyzed using Kaplan-Meier survival analysis. Cox proportional hazard regression analysis was used to assess prognostic factors for surgical failure.

RESULTS

IOP reduced from 32.37 ± 12.08 mmHg preoperatively to 15.14 ± 2.25 mmHg at 1 year (p = 0.001). The number of glaucoma medication reduced from 3.89 ± 0.32 preoperatively to 0.86 ± 1.35 at 1 year (p = 0.001). The success rates were 78.9% at 6 months and 73.7% at 1 year. Eyes with bleb horizontal extent ≥2 clock hours at 1 month postoperatively had a significantly higher success rate (log-rank test, p < 0.001). Greater bleb horizontal extent at 2 weeks and 1 month postoperatively was associated with a lower surgical failure rate (2 weeks: hazard ratio, 0.119; p = 0.024; 1 month: hazard ratio, 0.046; p = 0.007). Bleb needling and additional glaucoma surgeries were necessary in 10 (52.6%) and five eyes (26.3%), respectively.

CONCLUSIONS

XEN45 gel stent implantation with the open conjunctiva approach is effective in reducing IOP and glaucoma medication for over 1 year in patients with OAG.

Outcomes of reimplantation of a new Glaucoma Drainage Device after explantation of an older implant from exposure-related complications

Purpose

To describe the clinical outcome of a series of seven eyes with an explanation of an original Glaucoma Drainage Device (GDD) arising from the complication of plate exposure and consequent reimplantation of another GDD at a second setting.

Methods

This was a retrospective, interventional, and non-comparative study at two tertiary eye care hospitals in eastern and southern India. Electronic medical record data of the seven eyes where a GDD was explanted and a 2nd GDD was reimplanted over October 2010 and May 2021 was analyzed. Statistical analysis was done by SPSS (ver. 26).

Results

The first GDD survived for a mean of 168 days only till the plate got exposed and thereby got explanted. Possible predisposing factors noted were conjunctival and scleral thinning, ischemic conjunctiva, etc., The reimplantation surgery was technically easy in the absence of hypotony-opposite to what is reported in the literature. The final IOP (mean +/- SD) values (mm Hg) were 18.9 (+/-7.9), range = 10-30. The mean number of glaucoma medications reduced from 3.9 (+/-1.2; range, 2 to 5) after the explanation to 3.1 (+/-0.7; range, 2 to 4) after the 2nd GDD implantation, in the final follow-up. The second GDD was found to be stable till the last follow-up (mean = 1149 days). No other significant intraoperative or postoperative complications were seen.

Conclusions

Reimplantation of a second GDD in a separate setting after explanations of an original implant due to exposure-related complication is both a safe and effective method.

[Münster standard: modified Paul® implantation in a condition following Preserflo® MicroShunt implantation. Video article]

OBJECTIVE OF SURGERY

The aim of this surgical technique is the modified placement of a Paul® implant (Fa. Advanced Ophthalmic Innovations, Singapur) in eyes after failure of Preserflo® MicroShunt (Fa. Santen, Osaka, Japan) implantation for the best possible adjustment of the intraocular pressure.

INDICATIONS

The technique presented here is intended for patients suffering from more complex glaucomas, which were unsuccessfully previously treated with a Preserflo® Microshunt (Santen Inc.).

SURGICAL TECHNIQUE

The special feature of the Münster standard is the choice of the surgical field and the waiver of a further tunnel placement. The patients receive a Paul® implant in the same quadrant as the previously inserted Preserflo® MicroShunt implant (superior temporal). The latter is explanted after preparation of the conjunctiva and priming of the Paul® implant with a Prolene 6.0 suture and fixation of the plate. In order to carry out the implantation of the Paul® tube through the existing 25-gauge tunnel, the latter is dilated laterally with an iris spatula under positioning of the anterior chamber. A surgical video, which is available online, shows the surgical technique in detail. ADVANTAGES OF THE MüNSTER STANDARD: The superior temporal surgical access promises easier handling. The fact that there is no need for a new tunnel effectively saves surgery time and is expected to reduce endothelial cell loss as only one tube remains in place in comparison to two anterior chamber tubes.

PRESERFLO ™ MicroShunt versus trabeculectomy: 1-year results on efficacy and safety

PURPOSE

To compare the efficacy and safety of the PRESERFLO™ MicroShunt versus trabeculectomy in patients with primary open-angle glaucoma (POAG) after one year.

PATIENTS AND METHODS

Institutional prospective interventional cohort study comparing eyes with POAG, which had received the PRESERFLO™ MicroShunt versus trabeculectomy. The MicroShunt group was matched with the trabeculectomy group for age, known duration of disease, and number and classes of intraocular pressure (IOP) lowering medications to have similar conjunctival conditions. The study is part of the Dresden Glaucoma and Treatment Study, using a uniform study design, with the same inclusion and exclusion criteria, follow-ups and standardized definitions of success and failure for both procedures.

PRIMARY OUTCOME MEASURES

mean diurnal IOP (mdIOP, mean of 6 measurements), peak IOP, and IOP fluctuations.

SECONDARY OUTCOME MEASURES

success rates, number of IOP lowering medications, visual acuity, visual fields, complications, surgical interventions, and adverse events.

RESULTS

Sixty eyes of 60 patients, 30 in each group, were analyzed after 1-year follow-ups. Median [Q25, Q75] mdIOP (mmHg) dropped from 16.2 [13.8-21.5] to 10.5 [8.9-13.5] in the MicroShunt and from 17.6 [15.6-24.0] to 11.1 [9.5-12.3] in the trabeculectomy group, both without glaucoma medications. Reduction of mdIOP (P = .596), peak IOP (P = .702), and IOP fluctuations (P = .528) was not statistically significantly different between groups. The rate of interventions was statistically significantly higher in the trabeculectomy group, especially in the early postoperative period (P = .018). None of the patients experienced severe adverse events.

CONCLUSION

Both procedures are equally effective and safe in lowering mdIOP, peak IOP and IOP fluctuations in patients with POAG, one year after surgery.

CLINICAL TRIAL REGISTRATION

NCT02959242.

Gonioscopy-Assisted Transluminal Trabeculotomy for the Treatment of Glaucoma in Uveitic Eyes

PURPOSE

To evaluate the outcomes of gonioscopy-assisted transluminal trabeculotomy (GATT) in adult eyes with uncontrolled uveitic glaucoma.

METHODS

We reviewed 16 eyes from 13 patients. Surgical success was defined as intraocular pressure (IOP) reduction >20% from baseline or IOP between 5 and 21 mmHg by the 3-month visit while on a stable number or fewer IOP-lowering agents and no need for additional glaucoma surgery.

RESULTS

At 12 months, the cumulative success rate was 81%. Mean IOP was 37.8 ± 13.0 mmHg at baseline and 12.2 ± 3.0 mmHg at 12 months (68% reduction; p < .0001). The average number of glaucoma medications was 4.6 ± 1.3 at baseline and 2.2 ± 0.7 at 12 months (52% reduction; p < .0001). Transient hyphema was seen in 44% of eyes at 1 week.

CONCLUSIONS

This small retrospective study suggests that GATT is effective and safe as an initial surgical treatment for medically refractory glaucoma in uveitic adult eyes.

Recent Advancements in Glaucoma Surgery-A Review

Surgery has long been an important treatment for limiting optic nerve damage and minimising visual loss in patients with glaucoma. Numerous improvements, modifications, and innovations in glaucoma surgery over recent decades have improved surgical safety, and have led to earlier and more frequent surgical intervention in glaucoma patients at risk of vision loss. This review summarises the latest advancements in trabeculectomy surgery, glaucoma drainage device (GDD) implantation, and minimally invasive glaucoma surgery (MIGS). A comprehensive search of MEDLINE, EMBASE, and CENTRAL databases, alongside subsequent hand searches-limited to the past 10 years for trabeculectomy and GDDs, and the past 5 years for MIGS-yielded 2283 results, 58 of which were included in the final review (8 trabeculectomy, 27 GDD, and 23 MIGS). Advancements in trabeculectomy are described in terms of adjunctive incisions, Tenon's layer management, and novel suturing techniques. Advancements in GDD implantation pertain to modifications of surgical techniques and devices, novel methods to deal with postoperative complications and surgical failure, and the invention of new GDDs. Finally, the popularity of MIGS has recently promoted modifications to current surgical techniques and the development of novel MIGS devices.

Clinical Factors Impacting Outcomes From Failed Trabeculectomy Leading to Glaucoma Drainage Device Implantation and Subsequent Penetrating Keratoplasty

PRCIS

We evaluated the factors that impacted time from glaucoma drainage implant (GDI) surgery to penetrating keratoplasty (PK) in eyes with previously clear corneas (ie, GDI-first sequence), and that specifically underwent a trabeculectomy before GDI surgery for intraocular pressure (IOP) control.

PURPOSE

To describe through an event-triggered data collection method the clinical course and the long-term outcomes of 2 procedures that are commonly performed sequentially in complex clinical situations: GDI surgery and PK. The study investigates the clinical factors associated with the progression to PK and determines the GDI success rate and graft survival.

METHODS

A single, tertiary-care center retrospective interventional cases series including patients with a sequential history of trabeculectomy, GDI surgery, and PK from 1999 to 2009. Outcome measures included IOP, visual acuity, graft failure, GDI failure, and time from GDI to PK.

RESULTS

Of the eyes, 56% had primary open angle glaucoma. The time from the last trabeculectomy to GDI was 66.5 ± 66.7 months. Of the eyes, 84% received a Baerveldt GDI. Time from GDI to PK was 36.4 ± 28.4 months. IOP at the time of PK was between 5 mm Hg and 21 mm Hg in 90% of eyes. At the last follow-up, 48% of grafts were clear. At 5 years post-PK, 33% of corneal grafts remained clear, whereas 81% of tubes remained functional.

CONCLUSIONS

Nearly half of the corneal grafts are clear at the last long-term follow-up. Graft failure occurs at a higher rate than tube failure suggesting that IOP control is only one and possibly not the most important factor in graft survival in eyes with prior glaucoma surgery.

Comparison of Repeat Trabeculectomy Versus Ahmed Valve Implantation After Initial Failed Trabeculectomy Surgery

PRCIS

Repeat trabeculectomy is associated with similar postoperative intraocular pressure (IOP), a lower complication rate, and a lower need for medications when compared with Ahmed valve implantation (AVI) when performed after initially failed trabeculectomy.

OBJECTIVE

The goal of this study was to compare the efficacy of repeat trabeculectomies and AVI after an initial failed trabeculectomy.

METHODS

All studies that investigated the postoperative success of patients who underwent AVI or repeat trabeculectomy with mitomycin- C after a prior failed trabeculectomy with mitomycin- C found in PubMed, Cochrane Library, Scopus, and CINAHL were included. Mean preoperative and postoperative IOP, proportions of complete and qualified successes, and proportions of complications were extracted from each study. Meta-analyses were performed to compare the differences between the two surgical approaches. Methods of measuring complete and qualified success were too heterogeneous among the included studies to allow for meta-analysis.

RESULTS

The literature search yielded 1305 studies, and 14 studies were included in the final analysis. Mean IOP was not significantly different between the two groups preoperatively and then after 1, 2, and 3 years. Mean number of medications between the two groups was similar preoperatively. After 1 and 2 years, the mean amount of glaucoma medications in the AVI group was approximately twice that of the trabeculectomy group; however, this relationship was only significant at 1 year of follow-up ( P = 0.042). In addition, the cumulative proportion of overall and sight-threatening complications was significantly higher in the AVI group.

CONCLUSION

Repeat trabeculectomy with mitomycin- C and AVI may both be considered after failed primary trabeculectomy. However, our analysis suggests that repeat trabeculectomy may be the preferred method as it provides similar efficacy with fewer disadvantages.

Disparities in Glaucoma Surgery: A Review of Current Evidence and Future Directions for Improvement

There is a need to understand existing disparities in glaucoma surgery and to create strategies to eliminate these disparities. Disparities can exist in several aspects of glaucoma surgical management, including patient selection and timing of surgery, type of surgery performed, intra-operative and postoperative surgical complications, follow-up surgical care, and long-term surgical outcomes. Additionally, multiple types of disparities can exist within each of these realms, including disparities by race and ethnicity, age, gender, insurance type, people with disabilities, and other social, economic, and demographic factors. Disparities in glaucoma surgery have been examined in large scale datasets, retrospective clinical studies, and clinical trials, and several studies have identified likely racial and ethnic disparities in glaucoma surgical incidence and outcomes. We present existing literature on disparities in glaucoma surgery, analyze the advantages and limitations of various study designs for the investigation of these disparities, and propose directions for future research and interventions to identify and eliminate disparities in surgical glaucoma care.

Outcomes of XEN Stent in Patients With Glaucoma and Previous Corneal Transplantation

PRCIS

The XEN stent safely and effectively controls intraocular pressure in select patients with history of corneal transplantation.

PURPOSE

Glaucoma is a common complication after corneal transplantation and can be difficult to manage in these patients. This study reports outcomes of XEN stent implantation in eyes with glaucoma in the setting of previous corneal transplantation.

PATIENTS AND METHODS

Noncomparative retrospective case series including eyes with a history of corneal transplantation and subsequent XEN stent implantation by a single glaucoma surgeon in Surrey, British Columbia, between 2017 and 2022. The analysis included patient demographics, pre and postoperative intraocular pressure (IOP), pre and postoperative glaucoma medications, peri and postoperative complications and interventions, and incidence of repeat corneal transplantation and additional glaucoma procedures to control IOP.

RESULTS

Fourteen eyes with previous cornea transplantation underwent XEN stent implantation. Mean age was 70.1 years (range: 47-85 y). Mean follow-up was 18.2 months (range: 1.5-52 mo). The most common glaucoma diagnosis was secondary open angle glaucoma (50.0%). There was a significant reduction in IOP and the number of glaucoma agents at all postoperative time points ( P < 0.05). IOP decreased from 32.7 ± 10.0 mm Hg at baseline to 12.5 ± 4.7 mm Hg at the most recent follow-up. Glaucoma agents decreased from 4.0 ± 0.7 to 0.4 ± 1.0. Two eyes required additional glaucoma surgery to control IOP, with an average time to reoperation of 7 weeks. Two eyes underwent repeat corneal transplantation, with an average time to reoperation of 23.5 months.

CONCLUSIONS

In selected patients with previous corneal transplants and refractory glaucoma, the XEN stent was safely implanted and effectively reduced IOP in the short term.

10-Year Clinical Outcomes of Tube Shunt Surgery at a Tertiary Care Center

PURPOSE

To report 10-year clinical outcomes of tube shunt (TS) surgery at a tertiary care center.

DESIGN

Retrospective cohort study.

METHODS

Eyes were included that underwent a first TS surgery between January 2005 and December 2011 at a tertiary referral eye hospital and with at least 10 years of follow-up. Demographic and clinical data were collected. Failure was defined as reoperation to lower intraocular pressure (IOP), IOP > 80% of baseline for two consecutive visits, or progression to no light perception.

RESULTS

Eighty-five eyes of 78 patients were included in the Study Group; 89 eyes were selected as a Comparison Group. Mean follow-up was 11.9 ± 1.7 years. Fifty-one valved (60%), 25 non-valved (29%), and nine unknown (11%) TS were placed. At the final visit, mean IOP was reduced from 29.2 ± 10.4 mmHg on 3.1 ± 1.2 medications to 12.6 ± 5.8 mmHg on 2.2 ± 1.4 (p<0.001 for each). Forty-eight eyes (56%) failed; 29 eyes (34%) underwent additional glaucoma surgery; eight eyes (10%) progressed to no light perception; and 34 eyes (40%) also required TS revision. Best corrected visual acuity (BCVA) logMAR (minimal angle of resolution) worsened from 0.8 ± 0.7 (20/125) to 1.4 ± 1.0 (20/500) at the last visit (p<0.001). Average visual field MD was -13.9 ± 7.5 dB at baseline and -17.0 ± 7.0 dB at last follow-up (P=0.0605).

CONCLUSIONS

Many eyes maintained IOP control 10 years following TS, but 56% met failure criteria, 39% had substantial vision loss, and 34% underwent additional surgery. Outcomes did not differ with TS model. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Different patterns in the corneal endothelial cell loss after pars plana and pars limbal insertion of the Baerveldt glaucoma implant

PURPOSE

To assess corneal endothelial cell (CE) loss after pars plana (PP) and pars limbal (PL) insertion of a Baerveldt glaucoma implant (BGI).

DESIGN

Retrospective multicenter interventional comparative study.

METHODS

We studied central CE loss for 5 years after BGI surgery in 192 eyes.

RESULTS

The prevalence of bullous keratopathy (BK) was greater in the PL cohort than in the PP cohort (P = .003). The CE loss after simultaneous PP vitrectomy and tube insertion into the vitreous cavity was 11.9% in the first year, which was greater than that of 2.9% in eyes where the tube was inserted simply into the vitreous cavity after a prior vitrectomy (P = .046). The annual percentage CE loss after the first year decreased unidirectionally in both of those groups and was 1.3% and 1.0% in the fifth year, respectively (P < .001). For limbal insertion, the CE loss in the simple PL cohort was biphasic, decreasing from 10.5% in the first year to 7.0% in the fifth year. Simultaneous cataract and BGI surgery enhanced the CE loss slightly in the first year in the PP and PL cohorts to 13.0% and 14.0%, respectively. However, these increases were not significant (P = .816 and .358, respectively). Low preoperative CE density (P < .001) and insertion site (P = .020) were significant risk factors for the development of BK.

CONCLUSIONS

CE loss in the PL and PP cohorts was biphasic and unidirectional, respectively. The difference in annual CE loss became evident over time. PP tube implantation may be advantageous when the preoperative CE density is low.

Long-term outcomes of Baerveldt glaucoma implant surgery in Japanese patients

This study evaluated the long-term surgical outcomes of Baerveldt glaucoma implant (BGI) surgery in patients with refractory glaucoma (204 eyes/204 patients). Surgical failure was defined by: < 20% reduction in preoperative intraocular pressure (IOP), or criterion A (IOP > 21 mmHg), criterion B (IOP > 17 mmHg), or criterion C (IOP > 14 mmHg). Reoperation, loss of light perception vision, or hypotony also denoted failure. The probability of success at 5 years postoperatively using criteria A, B, and C was 72.4%, 49.7%, and 24.4%, respectively. The mean IOP decreased significantly from 32.7 ± 9.7 mmHg preoperatively to 13.1 ± 3.9 mmHg at 5 years; the mean number of glaucoma medications also decreased from 3.7 ± 1.2 to 1.8 ± 1.9 (both P < 0.01). The number of previous intraocular surgeries was significantly associated with failure in the multivariable analysis for criterion B (hazard ratio 1.30; P < 0.01) and criterion C (hazard ratio 1.19; P = 0.031). Early and late postoperative complications occurred in 82 (40.2%) and 28 (13.7%) eyes, respectively. Postoperative interventions were performed in 44 eyes (21.6%). BGI surgery resulted in significant long-term decreases in IOP and the number of glaucoma medications. BGI surgery is effective for refractory glaucoma. However, postoperative interventions due to complications are required in numerous cases.

The outcomes of a low-cost, non-valved glaucoma drainage device using mitomycin-C: 1-year results

PURPOSE

To evaluate the indications, outcomes, and complications of the usage of Aurolab Aqueous Drainage Implant (AADI) using mitomycin-C.

METHODS

A retrospective case series of patients who underwent AADI placement using mitomycin-C between April 2018 and June 2020 at Ain Shams University Hospitals, Cairo, Egypt. The data was extracted from the records of the patients with a minimum of 1 year of follow-up. Complete success was defined as IOP ≥ 5 mmHg and ≤ 21 mmHg or reduction of IOP by ≥ 20% from baseline without antiglaucoma medications (AGMs). Qualified success was defined as reaching the same IOP range with the aid of AGM.

RESULTS

A total of 50 eyes of 48 patients were included. Neovascular glaucoma represented the commonest indication (13 patients, 26%). The mean preoperative IOP was 34.0 ± 7.1 mmHg, with a median number of AGM of 3 (mean ± SD = 2.84 ± 1), while the mean IOP after 12 months was 14.3 ± 4 with a median number of AGM of 0. (mean ± SD = 0.52 ± 0.89) (p < 0.001). Complete success was achieved in 33 patients (66%). Qualified success was achieved in 14 patients (28%). Thirteen eyes (26%) had variable postoperative complications; none of them required explantation of the device or affected the visual acuity (except one patient).

CONCLUSION

AADI with using mitomycin-C and ripcord during the surgery is an effective and relatively safe method of control of IOP in refractory and advanced cases of glaucoma, with an overall success rate of 94%.

Will the PRESERFLO™ MicroShunt impact the future of trabeculectomy practice? A UK and Éire Glaucoma Society National Survey

BACKGROUND/OBJECTIVES

To explore the attitudes of UK glaucoma specialists regarding the current and future practice of trabeculectomy and the novel PRESERFLO™ MicroShunt (PF-MS) device, and intentions to adopt the PF-MS into routine glaucoma surgical practice.

METHODS

Online survey of UK and Éire Glaucoma Society members.

RESULTS

43 glaucoma consultants completed the survey. All surgeons performed trabeculectomies (median of 40 annually) and 51% undertook PF-MS procedures (median of 22.5 annually). The mean duration of surgery was reported as 48.9 (SD 13.3) and 31.2 (SD 9.9) min for trabeculectomy and PF-MS respectively (p < 0.0001). For surgeons not currently using the PF-MS, 65% planned to do so. Respondents judged completion of 35 trabeculectomies and 10 PF-MS were required to achieve basic competence. 91% of participants predicted their trabeculectomy volume would decrease and 73% expected PF-MS usage to increase. Respondents reported a median of six and four follow-ups within 3 months post surgery for trabeculectomy and PF-MS respectively (p < 0.0001). Respondents reported trabeculectomy required more post-operative interventions than the PF-MS and 81.8% judged the patient experience to be better with the PF-MS. The PF-MS was deemed suitable for early visual field loss by 72% of respondents, severe visual field loss by 35% and normal tension glaucoma by 21%.

CONCLUSION

The PF-MS has seen rapid adoption in the UK. Respondents predict its usage will significantly increase whilst trabeculectomies will decrease. They report the PF-MS is quicker to learn and perform, and requires less post-operative follow-ups and interventions which may facilitate a more efficient service delivery for patients requiring glaucoma surgery.

The Role of STAT3 Signaling Pathway Activation in Subconjunctival Scar Formation after Glaucoma Filtration Surgery

Scar formation resulting from overly active wound healing is a critical factor in the success rate of glaucoma filtration surgery (GFS). IL-6 and TGF-β have been implicated in the pathogenesis of fibrogenesis. In addition, the signal transducer and activator of transcription 3 (STAT3) can be activated by numerous cytokines and growth factors, including IL-6 and TGF-β1. Thus, STAT3 activation may integrate common profibrotic pathways to promote fibrosis. In this study, an increase in p-STAT3 was observed in activated HTFs. Inhibiting STAT3 in cultured HTFs by pharmacological inactivation reversed the fibrotic responses, such as fibroblast migration, the differentiation of resting fibroblasts into myofibroblasts and the deposition of ECM, mediated by IL-6 and TGF-β1. Moreover, the expression of suppressor of cytokine signaling 3 (SOCS3) was decreased in HTFs cultured with IL-6 and TGF-β1, and SOCS3 overexpression rescued ECM deposition, α-SMA expression and migration in IL-6- and TGF-β1-stimulated HTFs by inactivating STAT3. Finally, S3I-201 treatment inhibited profibrotic gene expression and subconjunctival fibrosis in a rat model of GFS. In conclusion, our data suggests that STAT3 plays a central role in fibrosis induced by different profibrotic pathways and that STAT3 is a potential target for antifibrotic therapies following GFS.

Outcomes of Glaucoma Reoperations in the Primary Tube Versus Trabeculectomy Study

PURPOSE

To describe the incidence and outcomes of reoperations for glaucoma in the Primary Tube Versus Trabeculectomy (PTVT) Study.

DESIGN

Cohort study of patients in a multicenter randomized clinical trial.

PARTICIPANTS

The PTVT Study enrolled 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery.

METHODS

Randomization assigned 125 patients to placement of a tube shunt (350-mm2 Baerveldt glaucoma implant) and 117 patients to trabeculectomy with mitomycin C (MMC, 0.4 mg/ml for 2 minutes). Data were analyzed from patients who underwent additional glaucoma surgery.

MAIN OUTCOME MEASURES

Outcome measures included intraocular pressure (IOP), use of glaucoma medications, visual acuity, surgical complications, and failure (IOP > 21 mmHg or reduced by <20%, IOP ≤ 5 mmHg, additional glaucoma surgery, or loss of light perception vision).

RESULTS

Additional glaucoma surgery was performed in 21 patients in the tube group and 12 patients in the trabeculectomy group in the PTVT Study, and the 5-year cumulative reoperation rate for glaucoma was 18.0% in the tube group and 10.4% in the trabeculectomy group (P = 0.15). Follow-up (mean ± standard deviation [SD]) after additional glaucoma surgery was 35.1 ± 17.7 months in the tube group and 30.1 ± 17.6 months in the trabeculectomy group (P = 0.44). At 3 years after glaucoma reoperation, IOP (mean ± SD) was 15.5 ± 4.8 mmHg in the tube group and 16.6 ± 7.3 mmHg in the trabeculectomy group (P = 0.71). The number of glaucoma medications (mean ± SD) after 3 years of follow-up was 2.1 ± 1.7 in the tube group and 1.7 ± 1.0 in the trabeculectomy group (P = 0.58). The cumulative probability of failure at 3 years after a glaucoma reoperation was 37.8% in the tube group and 21.3% in the trabeculectomy group (P = 0.47).

CONCLUSION

No significant difference in the rate of reoperation for glaucoma was observed after tube shunt implantation and trabeculectomy with MMC in the PTVT Study. Similar surgical outcomes were observed after additional glaucoma surgery, irrespective of the initial procedure to which the patient was randomized.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Four-year Surgical Outcomes of Gonioscopy-assisted Transluminal Trabeculotomy in Patients with Open-Angle Glaucoma

PURPOSE

To provide 4-year data on the efficacy and safety of gonioscopy-assisted transluminal trabeculotomy (GATT) in patients with open-angle glaucoma.

DESIGN

Retrospective case series.

PARTICIPANTS

Eyes of patients > 18 years of age who underwent GATT by a single surgeon at Wills Eye Hospital with at least 36 months follow-up.

METHODS

Postoperative changes in outcome measures including intraocular pressure (IOP), medication use and visual acuity were recorded. Failure was defined as IOP > 21 mmHg or less than 20% reduction below baseline at any postoperative visit after 3 months or need for further glaucoma surgery.

MAIN OUTCOME MEASURES

Main outcome measures were failure rate, IOP, number of glaucoma medications, and visual acuity at 4 years.

RESULTS

Fifty-nine patients (74 eyes), age 57.1 ± 18.5 years (37.8% female) underwent the GATT procedure. Average follow-up was 47.0 ± 6.7 months (range 35.6-76.5 months). Mean IOP was 27.0 ± 10.0 mmHg preoperatively and 14.8 ± 6.5 mmHg at 4 years (45% IOP decrease; P < 0.01). Mean number of medications decreased from 3.2 ± 1.0 preoperatively to 2.3 ± 1.0 at 4 years (P < 0.01). The cumulative failure rate at 4 years was 53.9%, and the cumulative reoperation rate was 42.0%. No significant differences between patients with primary open-angle glaucoma and other types of glaucoma were found.

CONCLUSIONS

Gonioscopy-assisted transluminal trabeculotomy can be a safe and effective conjunctival-sparing surgery for treating various forms of open-angle glaucoma at 4 years.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Ahmed Glaucoma Valve Implantation to Reduce Intraocular Pressure: Updated Perspectives

Trabeculectomy and glaucoma drainage device implantation are the most commonly performed glaucoma surgeries worldwide. Although trabeculectomy is the gold standard, at the present time there is an increase in the use of glaucoma drainage devices. The Ahmed glaucoma valve is one of the most widely used glaucoma drainage devices worldwide. Corneal endothelial cell loss and eventually corneal decompensation is one of the serious complication of glaucoma drainage device implantation. To avoid this, drainage tube can be inserted into the ciliary sulcus instead of the anterior chamber, especially in eyes with high risk for corneal decompensation. Tube/plate exposure, hypertensive phase, endophthalmitis, cataract formation, diplopia and ocular hypotony are the other potential complications that can develop after Ahmed glaucoma valve implantation.

Outcome of combined single-loop fixation of intraocular lens with Ahmed glaucoma valve implantation

A late adolescent girl presented with medically uncontrolled glaucoma and aphakia post-fire-cracker injury to the right eye. She underwent single-loop fixation of the posterior chamber intraocular lens (IOL) and Ahmed glaucoma valve (AGV) implantation with reduction of intraocular pressure (IOP) in the immediate postoperative period. She sustained second trauma 6 days later resulting in tube retraction and an IOP of 38 mm Hg. An anterior repositioning of the tube-plate complex was performed and IOP remained under control for 5 months. She then developed a tenon cyst and the IOP rose to 24 mm Hg, for which topical timolol and dorzolamide and digital massage were administered. The IOP was in the lower teens, sans medication and aided vision of 0.50 LogMAR at the 1 year follow-up. This case highlights the outcomes of single-loop fixation of IOL with AGV in a post-traumatic setting and subsequent management of complications.

The Success Rate of Glaucoma Drainage Device Revision

PRCIS

We report the survival of surgical revision to glaucoma drainage devices for several indications in a large cohort of patients, with an overall success rate of 45% at 36 months.

PURPOSE

To evaluate the outcomes of surgical revision for complications of glaucoma drainage devices.

METHODS

Three hundred thirty-five eyes of 318 patients who underwent tube revision or removal at University of California Los Angeles (UCLA) Jules Stein Eye Institute between 1997 and 2019 were included. The pre-defined primary outcome measure was surgical success of the initial revision, defined as resolution of the condition with no additional revisions required, no functionally significant change in vision, and no instances of intraocular pressure > 21 mmHg at 2 consecutive visits postoperatively. Kaplan-Meier survival analysis was applied to evaluate survival at 36 months based on these criteria. The Wilcoxon paired test was used to compare mean preoperative and postoperative intraocular pressure, medication usage, and visual acuity.

RESULTS

Overall, survival of revised tubes at 36 months was 45%. The 4 most common indications for revision were exposure of the implant (42% of all revisions), occlusion (14%), corneal failure or threat of failure (12%), and hypotony (11%). Survival at 36 months for each of these indications was 44%, 45%, 52%, and 37%, respectively.

CONCLUSIONS

These results suggest that eyes with glaucomatous damage with long-term glaucoma drainage device complications can still have a reasonably successful outcome when a revision is performed. However, with substantial rates of vision loss and a frequent need for additional revisions to manage complications, managing patient expectations for success and making them aware of the likelihood of additional surgeries or failure is important.

Prevalence of hypertensive phase and outcomes in patients with Ahmed valve implantation at one year of follow-up and evaluation of associated risk factors

Purpose

To evaluate the prevalence of hypertensive phase (HP) and failure in patients who underwent Ahmed Glaucoma Valve (AGV) implantation and identify the possible risk factors for both HP and failure.

Methods

A cross-sectional, observational study was conducted. Medical records of patients who underwent AGV implantation and had at least 1 year of follow-up were reviewed. HP was defined as an intraocular pressure (IOP) greater than 21 mmHg between the first week and the third postoperative month not attributable to other causes. Success was defined as an IOP between 6 and 21 mmHg, with preservation of light perception and no additional glaucoma surgeries. Statistical analysis was conducted to identify possible risk factors.

Results

A total of 193 eyes of 177 patients were included. HP was present in 58%; a higher preoperative IOP and younger age were associated with HP. Pseudophakic or aphakic eyes had a lower HP rate. Failure was present in 29%; neovascular glaucoma, worse basal best corrected visual acuity (BCVA), higher baseline IOP, and postoperative complications were linked to a higher likelihood of failure. No difference in the HP rate between the failure and success groups was found.

Conclusion

A higher baseline IOP and younger age are associated with HP development; pseudophakia and aphakia might be protective factors. Factors for AGV failure are a worse BCVA, neovascular glaucoma, postoperative complications, and a higher baseline IOP. At 1 year, a higher number of medications were needed to achieve IOP control in the HP group.

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.

Comparison of tube shunt implantation and trabeculectomy for glaucoma: a systematic review and meta-analysis

OBJECTIVE

To compare the efficacy and safety of tube shunt implantation with trabeculectomy in the treatment of patients with glaucoma.

METHODS

A systematic literature search was performed for studies comparing tube with trabeculectomy in patients with glaucoma (final search date: 27 February 2022). Comparisons between tube and trabeculectomy were grouped by the type of tube (Ahmed, Baerveldt, Ex-PRESS and XEN). The primary endpoints included intraocular pressure (IOP), IOP reduction (IOPR), IOPR percentage (IOPR%), complete success rate (CSR), qualified success rate (QSR) and adverse events (AEs).

RESULTS

Forty-nine studies were included in this meta-analysis and presented data for 3795 eyes (Ahmed: 670, Baerveldt: 561, Ex-PRESS: 473, XEN: 199, trabeculectomy: 1892). Ahmed and Ex-PRESS were similar to trabeculectomy in terms of IOP outcomes and success rate (Ahmed vs trabeculectomy: IOPR%: mean difference (MD)=1.34 (-5.35, 8.02), p=0.69; Ex-PRESS vs trabeculectomy: IOPR%: MD=0.12 (-3.07, 3.31), p=0.94). The IOP outcomes for Baerveldt were worse than those for trabeculectomy (IOPR%: MD=-7.51 (-10.68, -4.35), p<0.00001), but the QSR was higher. No significant difference was shown for the CSR. XEN was worse than trabeculectomy in terms of IOP outcomes (IOPR%: MD=-7.87 (-13.55, -2.18), p=0.007), while the success rate was similar. Ahmed and Ex-PRESS had a lower incidence of AEs than trabeculectomy. Baerveldt had a lower incidence of bleb leakage/wound leakage, hyphaema and hypotonic maculopathy than trabeculectomy but a higher incidence of concurrent cataracts, diplopia/strabismus and tube erosion. The incidence of AEs was similar for the XEN and trabeculectomy procedures.

CONCLUSION

Compared with trabeculectomy, both Ahmed and Ex-PRESS appear to be associated with similar ocular hypotensive effects and lower incidences of AEs. However, Baerveldt and XEN cannot achieve sufficient reductions in IOP outcomes similar to those of trabeculectomy.

PROSPERO REGISTRATION NUMBER

CRD42021257852.

Design of medical tympanostomy conduits with selective fluid transport properties

Implantable tubes, shunts, and other medical conduits are crucial for treating a wide range of conditions from ears and eyes to brain and liver but often impose serious risks of device infection, obstruction, migration, unreliable function, and tissue damage. Efforts to alleviate these complications remain at an impasse because of fundamentally conflicting design requirements: Millimeter-scale size is required to minimize invasiveness but exacerbates occlusion and malfunction. Here, we present a rational design strategy that reconciles these trade-offs in an implantable tube that is even smaller than the current standard of care. Using tympanostomy tubes (ear tubes) as an exemplary case, we developed an iterative screening algorithm and show how unique curved lumen geometries of the liquid-infused conduit can be designed to co-optimize drug delivery, effusion drainage, water resistance, and biocontamination/ingrowth prevention in a single subcapillary-length-scale device. Through extensive in vitro studies, we demonstrate that the engineered tubes enabled selective uni- and bidirectional fluid transport; nearly eliminated adhesion and growth of common pathogenic bacteria, blood, and cells; and prevented tissue ingrowth. The engineered tubes also enabled complete eardrum healing and hearing preservation and exhibited more efficient and rapid antibiotic delivery to the middle ear in healthy chinchillas compared with current tympanostomy tubes, without resulting in ototoxicity at up to 24 weeks. The design principle and optimization algorithm presented here may enable tubes to be customized for a wide range of patient needs.

Delayed Suprachoroidal Hemorrhage After Xen45 Gel Stent

PRCIS

In patients with significant preoperative comorbidities, prolonged activity restrictions beyond 2 weeks after Xen45 surgery may mitigate the risks of delayed SCH.

PURPOSE

To report the first case to date of delayed suprachoroidal hemorrhage (SCH) not associated with hypotony 2 weeks after the placement of the Xen45 gel stent.

CASE SUMMARY

An 84-year-old white man with significant cardiovascular comorbidities underwent uneventful ab externo implantation of a Xen45 gel stent for asymmetric progression of severe primary open angle glaucoma. The patient had a reduction in intraocular pressure by 11 mm Hg on postoperative day 1 and maintained preoperative visual acuity. The intraocular pressure remained stable at 8 mm Hg on multiple postoperative visits until the patient developed a SCH at postoperative week 2 immediately after a light session of physical therapy. The patient was treated medically with topical cycloplegic, steroid, and aqueous suppressants. He maintained preoperative visual acuity throughout the postoperative course and had resolving SCH without the need for surgical intervention.

CONCLUSIONS

This is the first report of a delayed presentation of SCH in the absence of hypotony after ab externo implantation of the Xen45 device. The possibility of this vision-threatening complication should be considered as part of the risk assessment and included in the consent process for the gel stent. In patients with significant preoperative comorbidities, prolonged activity restrictions beyond 2 weeks after Xen45 surgery may mitigate the risks of delayed SCH.

Scar formation in the presence of mitomycin C and the anti-fibrotic antibody in a rabbit model of glaucoma microsurgery: A pilot study

Purpose

This study aimed to evaluate the utility of a rationally engineered antibody that directly blocks collagen fibrillogenesis to reduce scar tissue formation associated with subconjunctival glaucoma surgery.

Material and methods

Fourteen eyes of 7 adult rabbits underwent glaucoma filtering surgery using XEN 45 Gel Stent. The rabbits' eyes were divided randomly into three treatment groups: (i) treated with the antibody, (ii) treated with mitomycin C, and (iii) treated with the antibody and mitomycin C. Following surgeries, the intraocular pressure and bleb appearance were evaluated in vivo. The rabbits were sacrificed 8 weeks after the surgery, and their eyes were harvested and processed for tissue analysis. Subsequently, tissue samples were analyzed microscopically for fibrotic tissue and cellular markers of inflammation. Moreover, the collagen-rich fibrotic tissue formed around the stents was analyzed using quantitative histology and infrared spectroscopy. The outcomes of this study were analyzed using the ANOVA test.

Results

This study demonstrated no significant differences in intraocular pressure, bleb appearance, or presence of complications such as bleb leak among the treatment groups. In contrast, we observed significant differences among the subpopulations of collagen fibrils formed within scar neo-tissue. Based on the spectroscopic analyses, we determined that the relative content of mature collagen cross-links in the antibody-treated group was significantly reduced compared to other groups.

Conclusions

Direct blocking of collagen fibrillogenesis with the anti-collagen antibody offers potentially beneficial effects that may reduce the negative impact of the subconjunctival scarring associated with glaucoma filtering surgery.

Safety and Efficacy of Ab Interno XEN 45 Gel Stent in Patients with Glaucoma and High Myopia

This study reports on the safety and efficacy of Xen 45 in patients with glaucoma and high myopia. It was a retrospective study including patients with high myopia (>6D) who underwent Xen implant with 2 years of follow-up. The primary outcome was to report the incidence of hypotony (IOP ≤ 5 mmHg) and hypotony-related complications. Patients with high myopia treated with mitomycin-C-augmented trabeculectomy were included as a control group. We included 14 consecutive patients who underwent Xen implant (seven eyes) and trabeculectomy (seven eyes). The mean myopia was −14.71 ± 5.36 and −15.07 ± 6.11 in the trabeculectomy and Xen groups, respectively (p > 0.05). The success rate and the mean IOP at 1 and 2 years from the intervention were statistically comparable between the two groups. The group undergoing trabeculectomy showed a higher incidence of hypotony (six eyes (85.71%) vs. two eyes (28.57%)) and hypotony maculopathy (three eyes (42.86%) vs. zero eyes (0%)) and required more postoperative procedures. Patients with high myopia were at higher risk of hypotony-related complications after trabeculectomy. The Xen implant can achieve an IOP control comparable to trabeculectomy with a significantly better safety profile and can be considered as an option for the management of patients with high myopia and glaucoma.

Subconjunctival filtration in evolution: current evidence on MicroShunt implantation for treating patients with glaucoma

BACKGROUND

Although traditional surgical procedures for glaucoma (such as trabeculectomy and tube-shunt implantation) can significantly reduce intraocular pressure (IOP), they are associated with numerous complications, some of which are vision-threatening, or involve prolonged recovery or a highly intensive postoperative course. Micro-invasive glaucoma surgery (MIGS) procedures have shown better safety but reduced efficacy in achieving target IOP. Combinations of these methods have led to the development of subconjunctival micro-invasive procedures with safety comparable to traditional surgery and greater efficacy than minimally invasive methods. This review describes the use of one of these devices, the poly(styrene-block-isobutylene-block-styrene) (SIBS)-based PreserFlo MicroShunt (Santen, Emeryville, CA), in the surgical treatment of patients with glaucoma.

MAIN TEXT

The MicroShunt is an 8.5-mm tube made of an inert polymer with no endplate, an internal diameter of 70 μm, and fins intended to prevent peritubular flow and anchor the device within the sclera to prevent proximal migration into the eye. Following ab externo implantation, the tube provides a conduit for flow of aqueous humor from the anterior chamber into the subconjunctival/sub-Tenon space. Clinical trials to date have shown that, when paired with mitomycin C (MMC) treatment, MicroShunt implantation significantly reduced both IOP and the number of glaucoma medications. These IOP-lowering results were found both when surgery was performed alone and with phacoemulsification. The MicroShunt also showed a safety profile comparable to that of traditional filtering surgery.

CONCLUSIONS

The MicroShunt and other novel subconjunctival procedures have shown substantial IOP reductions while mitigating hypotony-related complications. MMC, which modulates fibrosis and scarring postoperatively, is essential to surgical success. Randomized, long-term clinical trials will further clarify the role of controlled micro-incisional device-assisted ab externo glaucoma filtering surgery in long-term glaucoma management.

Results from the Primary Tube Versus Trabeculectomy Study and translation to clinical practice

PURPOSE OF REVIEW

The Primary Tube Versus Trabeculectomy (PTVT) Study is a multicenter randomized clinical trial comparing the safety and efficacy of tube shunt surgery and trabeculectomy with mitomycin C (MMC) in eyes without previous incisional ocular surgery. This article reviews results from the PTVT Study and suggests how they may be translated to clinical practice.

RECENT FINDINGS

Tube shunt surgery had a higher failure rate than trabeculectomy with MMC in the PTVT Study, and the difference was statistically significant at 1 year but not at 3 years and 5 years. Both surgical procedures reduced intraocular pressure (IOP) to the low teens throughout 5 years of follow-up. Mean IOPs were lower after trabeculectomy with MMC compared with tube shunt implantation, and the differences were statistically significant during the first postoperative year and at 3 years. The greater IOP reduction after trabeculectomy with MMC was achieved with significantly fewer glaucoma medications relative to tube shunt placement. Surgical complications were common in the PTVT Study, but most were transient and self-limited. The incidence of early postoperative complications was significantly higher after trabeculectomy with MMC than tube shunt surgery. The rates of late postoperative complications, cataract progression, and vision loss were similar with both surgical procedures. Serious complications producing vision loss and/or requiring a reoperation to manage the complication developed more frequently after trabeculectomy with MMC compared with tube shunt surgery, and the difference was statistically significant at 1 year but not at 3 years and 5 years postoperatively.

SUMMARY

Tube shunt implantation and trabeculectomy with MMC are both viable surgical options for managing glaucoma in patients without previous incisional ocular surgery. Results from the PTVT Study support further expansion of tube shunt use beyond refractory glaucomas.

Long-Term Safety and Outcomes of β-radiation for Trabeculectomy

PRCIS

β-radiation is a neglected antiscarring therapy with past concerns for safety. This report found it safe and efficacious when used as an adjuvant to trabeculectomy surgery in 101 people (135 eyes) over 20 years.

PURPOSE

β-radiation has been used as an adjunct to prevent scarring in trabeculectomy surgery for many decades. Safety concerns were raised with the use of high doses on the bare sclera. Moorfields Eye Hospital has a large cohort of patients who have received β-radiation therapy. We report a review of the long-term safety and efficacy.

METHODS

Cases undertaken between August 1992 and August 1996 were reviewed. Those with records available for postoperative review of more than 5 years were included. Failure (reintervention/>21 mm Hg on 2 successive occasions) and any complication previously reported in association with β-radiation were the primary outcomes.

RESULTS

In total, 292 operations using β-radiation were recorded and 101 people (135 eyes) with trabeculectomy surgery and postoperative follow-up for over 4.5 years were included. The median follow-up period was 22.5 years. At the final follow-up, 48 (48%) single eyes per person had failed and 20/51 (51%) eyes with primary open angle glaucoma had cataract surgery. Other complications were rare and associated with copathology.

CONCLUSION

In glaucoma patients at risk of scarring and failure after trabeculectomy, as an antiscarring adjuvant, a 750 cGY dose of β-radiation was found to be safe and efficacious in the long term.

Development of a Novel Valve-Controlled Drug-Elutable Microstent for Microinvasive Glaucoma Surgery: In Vitro and Preclinical In Vivo Studies

Purpose

Microinvasive glaucoma surgery (MIGS) has become an important treatment approach for primary open-angle glaucoma, although the safe and long-term effective lowering of intraocular pressure with currently available implants for MIGS is not yet achieved to a satisfactory extent. The study focusses on the development and in vitro and in vivo testing of a novel microstent for MIGS.

Methods

A silicone elastomer-based microstent was developed. Implants were manufactured using dip coating, fs-laser cutting, and spray coating. Within the current study no antifibrotic drug was loaded into the device. Sterilized microstents were analyzed in vitro regarding pressure-flow characteristics and biocompatibility. Six New Zealand white rabbits were implanted with a microstent draining the aqueous humor from the anterior chamber into the subconjunctival space. Drainage efficacy was evaluated using oculopressure tonometry as a transient glaucoma model. Noninvasive imaging was performed.

Results

Microstents were manufactured successfully and characterized in vitro. Implantation in vivo was successful for four animals with additional device fixation. Without additional fixation, dislocation of microstents was found in two animals. Safe and effective intraocular pressure reduction was observed for the four eyes with correctly implanted microstent during the 6-month trial period.

Conclusions

The described microstent represents an innovative treatment approach for MIGS. The incorporation of a selectively antifibrotic drug into the microstent drug-elutable coating will be addressed in future investigations.

Translational Relevance

The current preclinical study successfully provided proof of concept for our microstent for MIGS which is suitable for safe and effective intraocular pressure reduction and offers promising perspectives for the clinical management of glaucoma.