Hydrus microstent compared to selective laser trabeculoplasty in primary open angle glaucoma: one year results

Effectiveness of Angle-Based Minimally Invasive Glaucoma Surgery after Laser Trabeculoplasty: An Analysis of the IRIS® Registry (Intelligent Research in Sight)

OBJECTIVE

Angle-based minimally invasive glaucoma surgery (ab-MIGS) has grown substantially, although long-term efficacy is poorly understood. We analyze ab-MIGS effectiveness with and without preceding laser trabeculoplasty (LTP).

DESIGN

Retrospective cohort study.

SUBJECTS

Eyes undergoing ab-MIGS (Canaloplasty, Goniotomy, Trabectome, and iStent) with and without prior laser trabeculoplasty (< 2 years preceding MIGS) were identified in the IRIS® Registry (Intelligent Research in Sight) 2013 to 2018.

METHODS

Propensity score matching (PSM) was undertaken to define the following 4 cohorts: (1) standalone ab-MIGS, no prior LTP vs. (2) standalone ab-MIGS, with prior LTP; and (3) ab-MIGS + phacoemulsification, no prior LTP vs. (4) ab-MIGS + phacoemulsification, with prior LTP.

MAIN OUTCOME MEASURES

Failure was defined as subsequent glaucoma reoperation after ab-MIGS (either MIGS or traditional glaucoma surgery). Time-to-event outcome and incidence rates were calculated using survival analysis, and adjusted hazard ratios (aHRs) were generated using multivariate Cox proportional hazards models. Medication data were not available for analysis.

RESULTS

A total of 164 965 unique MIGS procedures were performed, from 2013 to 2018. After PSM, we identified 954 eyes undergoing standalone ab-MIGS and 7522 undergoing ab-MIGS + phacoemulsification. For eyes undergoing standalone ab-MIGS, those with prior LTP (n = 477) were more likely to undergo reoperation vs. those without LTP (n = 477) at 6 and 12 months. In multivariable models, those with prior LTP were more likely to undergo reoperation over the 36-month period vs. those without prior LTP (aHR, 1.53; CI, 1.15-2.04; P = 0.004). For eyes undergoing ab-MIGS + phacoemulsification, those with prior LTP (n = 3761) were more likely to undergo reoperation vs. those without LTP (n = 3761) at 12, 24, and 36 months. In multivariable models, those with prior LTP were more likely to undergo reoperation over the 36-month period vs. those without prior LTP (aHR, 1.53 CI, 1.15-2.04; P = 0.004).

CONCLUSIONS

Prior LTP may be associated with a higher chance of subsequent glaucoma surgery following ab-MIGS, either with or without concurrent phacoemulsification. These findings have important implications for understanding who may benefit most from ab-MIGS, and for guiding patient and surgeon treatment expectations.

FINANCIAL DISCLOSURES

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

Mid-term real world outcomes of the Hydrus® Microstent in open angle glaucoma

PURPOSE

To evaluate the mid-term clinical results and the safety aspects of the Hydrus® Microstent (Ivantis, Inc, Irvine, CA) in a real-life setting.

DESIGN

Retrospective case series.

METHODS

Hydrus® Microstent was implanted in phakic eyes (88 eyes, 87.1%) and in pseudophakic eyes (13 eyes, 12.9%), respectively. Mean follow-up time was 16 ± 9 months with 27 eyes having a follow-up time of more than 24 months.

MAIN OUTCOME MEASURES

The primary endpoint was reduction in IOP compared to baseline. Target IOP levels were set at ≤20 mmHg, ≤18 mmHg and ≤15 mmHg. Kaplan-Meier survival was defined as a reduction in IOP of ≥20% compared to baseline. Secondary endpoints were reduction in number of glaucoma medications and safety assessments addressing visual acuity, adverse events, re-surgery rate and identification of factors that made the implantation more difficult.

RESULT

101 eyes underwent Hydrus® implantation. The mean preoperative IOP was 21.60 mmHg (SD 6.6) on 2.18 (SD 1.3) medications. After a mean follow up time of 16 months, the mean IOP was reduced to 14.61 ± 3.7 mmHg on 1.12 (SD 1.1) medication classes (p < 0.001). Mean decrease in IOP was 26.7%. Analysis of the target IOP levels showed that in 29%, 34% and 35% of cases an IOP of ≤15 mmHg, ≤18 mmHg and ≤20 mmHg respectively could be achieved. BCVA improved from 0.56 ± 0.3 at baseline to 0.85 ± 0.3 more than 24 months after surgery (p < 0.001). The rate of re-operation was low at <3%. Adverse events occurred in 4 eyes (<4%).

CONCLUSION

This study underlines the effectiveness and the safety of the Hydrus® Microstent in an elective setting, but it also demonstrates certain limits and risk factors of this procedure.

Two-Year Performance and Safety Results of the MINIject Supraciliary Implant in Patients With Primary Open-Angle Glaucoma: Meta-Analysis of the STAR-I, II, III Trials

PURPOSE

To evaluate the performance and safety of minimally invasive glaucoma surgery with a supraciliary drainage device (MINIject; iSTAR Medical, Wavre, Belgium) in primary open-angle glaucoma (POAG) as a stand-alone procedure.

DESIGN

Meta-analysis.

METHODS

At 11 sites in Colombia, France, Germany, India, Panama, and Spain, 82 patients were treated in 3 prospective, multicenter, interventional, nonrandomized trials (STAR-I, II, III). Data were pooled in a meta-analysis of up to 2 years of follow-up postimplantation. The main outcome measures were mean relative and absolute reduction in diurnal intraocular pressure (IOP) compared to baseline. Secondary outcomes included patients with IOP ≤18 mmHg, patients with IOP reduction ≥20%, number of IOP-lowering medications, adverse events, and endothelial cell density loss.

RESULTS

At the 2-year follow-up (n = 66), mean IOP was reduced from 23.8 ± 3.3 mmHg at baseline to 14.4 ± 4.5 mmHg (-39.3%; P < 0.0001). An IOP reduction of ≥20% was achieved in 89.4% of patients, with 84.8% having an IOP ≤18 mmHg. IOP-lowering medications were reduced from a mean of 2.4 ± 1.1 to 1.4 ± 1.4 (P < 0.0001), with 37.9% of patients being medication-free at 2 years. Mean endothelial cell density loss at 2 years was 6.2 ± 9.1% compared to baseline and no patient had a loss >30%.

CONCLUSIONS

This meta-analysis demonstrates the favorable safety and efficacy profile of a supraciliary device implanted in a stand-alone, ab-interno procedure in patients with mild-to-moderate POAG. The data demonstrate that MINIject is a safe and effective, bleb-free treatment option for patients requiring low target IOP up to 2 years.

Biotissue stent for supraciliary outflow in open-angle glaucoma patients: surgical procedure and first clinical results of an aqueous drainage biostent

BACKGROUND/AIMS

To report a first-in-human trial in open-angle glaucoma (OAG) subjects treated with a new microinterventional biostent-reinforced cyclodialysis technique to enhance supraciliary aqueous drainage.

METHODS

Subjects (N=10; 74.1±7.9 years old) with OAG and cataracts underwent combined phacoemulsification cataract surgery with implantation of a permanent endoscleral supraciliary biostent to reinforce a controlled cyclodialysis cleft. The biostent comprised decellularised scleral allograft tissue microtrephined into a polymer tubular implant intraoperative/postoperative safety, intraocular pressure (IOP) and glaucoma medications were tracked through 12 months postimplantation.

RESULTS

Baseline medicated IOP averaged 24.2±6.9 mm Hg with subjects using 1.3±0.8 IOP-lowering medications. Successful biostent implantation was achieved in all individuals without significant complications. Immediate IOP lowering was sustained through 1 year. Twelve-month mean IOP was reduced 40% from baseline to 14.6±3.2 mm Hg (p=0.004; paired two-tailed t-test), and 80% of patients achieved >20% IOP reduction. Biostenting reduced glaucoma medication use 62%, from a baseline mean of 1.3 required medications to 0.5 medications (p=0.037) at postoperative 12 months. The biotissue implant was well tolerated and demonstrated good endothelial safety with only 11% endothelial cell loss at 12 months after combined phaco-biostenting surgery, similar to that expected after phacoemulsification alone. Mean BCVA increased from baseline 20/130 Snellen to 20/36 at postoperative 12 months (p=0.001).

CONCLUSION

Supraciliary biostenting in OAG patients is well tolerated, has a good safety profile and produces long-term IOP-lowering while reducing glaucoma medication requirements.

Glaucoma Surgery Shifts Among Medicare Beneficiaries After 2022 Reimbursement Changes in the United States

PRCIS

This study revealed the best-estimated surgical procedural counts for 2021 and 2022 and suggests a direct influence of coding and reimbursement changes on surgical device selection.

PURPOSE

To analyze utilization rates of glaucoma surgeries and minimally invasive (microinvasive) glaucoma surgery among US Medicare beneficiaries between 2021 and 2022.

DESIGN

Retrospective comparative analysis of 68,118 unique patients.

METHODS

National claims data from a 5% sample of all Medicare beneficiaries were utilized to compare glaucoma procedure counts between the first quarter of 2021 and the first quarter of 2022. Duplicate claims were excluded, and 50 modifiers were counted as 2 distinct procedures. A multiplier was applied to estimate annual utilization for the entire Medicare population. χ 2 analysis was employed to compare categorical data from the 2 time periods.

RESULTS

Current Procedural Terminology codes for angle-based stenting decreased by an estimated 20,960 procedures between 2021 and 2022 (28.60%). Goniotomy increased by an estimated 11,680 procedures (66.97%) and canaloplasty increased by an estimated 6640 procedures (47.43%). Glaucoma surgeries decreased by an estimated 5760 procedures (4.25%) despite an increase of cataract surgery by 234,960 procedures (15.63%), an increase in YAG capsulotomy by 19,280 procedures (3.31%), and an increase in intravitreal injections by 146,320 procedures (3.86%).

CONCLUSION

Despite overall surgical volume increases among the ophthalmology procedures, angle-based stenting utilization decreased significantly with an accompanying trend change following the coding and reimbursement changes implemented in January 2022. Of the minimally invasive (microinvasive) glaucoma surgery procedures, goniotomy and canaloplasty counts increased the most between these periods. Trabeculectomy and glaucoma drainage device procedures continued to decrease, following well-established trends. Future studies are warranted to examine how these shifts in utilization may impact patient care outcomes.

First-in-Human Safety Study of Femtosecond Laser Image-Guided Trabeculotomy for Glaucoma Treatment: 24-month Outcomes

Purpose

Pilot study to evaluate adverse events and intraocular pressure (IOP)-lowering of a novel, noninvasive glaucoma procedure, femtosecond laser, image-guided, high-precision trabeculotomy (FLIGHT).

Design

Prospective, nonrandomized, single-center, interventional, single-arm clinical trial.

Participants

Eighteen eyes from 12 patients with open-angle glaucoma.

Methods

Eighteen eyes from 12 patients underwent FLIGHT, creating a single channel measuring 500-μm wide by 200-μm high through the trabecular meshwork and into Schlemm's canal. Adverse events, IOP, and other parameters were evaluated out to 24 months.

Main Outcome Measures

Outcomes were the rates and types of adverse events and the rate of postprocedure best-corrected visual acuity loss (≥ 2 lines) compared with baseline. Efficacy outcomes were reduction in mean intraocular pressure (IOP) with respect to baseline and the percentage of eyes with a ≥ 20% reduction in IOP.

Results

Eighteen eyes from 12 patients were enrolled in the study; 11 patients (17 eyes) returned at 24 months. There were no serious adverse events related to the laser treatment. Well-defined channels were clearly visible at 24 months by gonioscopy and anterior segment OCT, with no evidence of closure. At 24 months, the mean IOP was reduced by 34.6% from 22.3 ± 5.5 to 14.5 ± 2.6 mmHg (P < 5e-5), with an average of 2.0 ± 1.2 hypotensive medications compared with 2.2 ± 1.1 at baseline (P = 0.22). Fourteen out of the 17 study eyes (82.3%) achieved a ≥ 20% reduction in IOP at 24 months when compared with baseline.

Conclusion

The FLIGHT system demonstrated a favorable safety profile in this initial pilot study, with no device-related serious adverse events. The channels appeared patent at 24 months, indicating medium-term durability.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

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.

Preventing Blindness with Early Cataract Surgery and Micro-Invasive Glaucoma Surgery in Patients Over 50: Guidance for Patients, Physicians and World Governments in Dealing with Glaucoma

Purpose

To offer clinical guidance and address safety and efficacy concerns regarding the growing use of micro-invasive glaucoma surgery (MIGS) as an initial treatment for glaucoma in adult patients.

Design

Narrative literature review.

Methods

A review was conducted to assess outcomes and complications of MIGS in the treatment of glaucoma, both alone and in combination with lens replacement. These outcomes were compared with those of standard glaucoma surgery and/or glaucoma management with medication.

Results

MIGS are effective at lowering intraocular pressure (IOP) over long periods of follow-up. These techniques share a similarly high safety profile between one another. MIGS were found to have lower complication rates and to be more effective in reducing the total amount of medication needed to maintain control of intraocular pressure than standard surgery approaches.

Conclusion

MIGS techniques are growing in popularity and have been demonstrated to be a safe and effective alternative to standard glaucoma surgery. Guidance in the implementation of these procedures has been outlined.

Hydrus microstent for the treatment of primary open-angle glaucoma: overview of its safety and efficacy

INTRODUCTION

Minimally invasive glaucoma surgeries (MIGS) are now a consolidated reality in many surgical units. The Hydrus Microstent is one of several MIGS devices bypassing trabecular outflow and had excellent results over the years. This article aims to review the key features of the Hydrus Microstent in terms of design, efficacy, and safety.

AREAS COVERED

The present review analyses the main characteristics of the device by evaluating the technical and physical details of its functioning. The evidence that supports a clinical decision summarizes the most influential clinical trials and the most accurate systematic reviews.

EXPERT OPINION

The Hydrus device has been extensively studied regarding biocompatibility and outflow potential. The subsequent clinical studies have been well-built and proved that the device effectively reduces intraocular pressure (IOP) and the eyedrop load. The device covers almost a quarter of Schlemm's canal circumference, offering at least two advantages: cannulating the Schlemm's canal provides evidence that the device has been implanted correctly; covering a larger area potentially allows to target multiple collector channels or at least areas of active outflow. This scaffold may prove more effective in naïve patients or subjects who used antiglaucoma eyedrops for a limited period, as the prolonged use of hypotonic medications has been associated with the surgical failure of ab interno microhook trabeculotomy.

The budget impact of introducing the OMNI® surgical system to a United States health plan for managing mild-to-moderate primary open-angle glaucoma

OBJECTIVES

Minimally invasive glaucoma surgery devices fill an unmet need in the treatment paradigm between topical intraocular pressure medicines and more invasive filtration procedures. This study evaluated the adoption of The OMNI® Surgical System with or without cataract surgery in primary open-angle glaucoma patients.

METHODS

A budget impact analysis estimated costs before and after adoption of OMNI® to a hypothetical US health plan with 1 million Medicare-covered lives over two years. Model input data were derived from published sources and development of the model included primary research with key opinion leaders and payers. The model compared total annual direct costs for OMNI® versus other treatment options (medications, other minimally invasive surgical procedures, selective laser trabeculoplasty) to calculate budget impact. A one-way sensitivity analysis was conducted to assess parameter uncertainty.

RESULTS

Increased adoption of OMNI® resulted in budget neutrality over the two years with a decrease in total costs of $35,362. Per member per month incremental costs were $0.00 when used without cataract surgery and yielded cost savings of -$0.01 when used with cataract surgery. Sensitivity analysis confirmed model robustness and identified surgical center fee variability as a key driver of costs.

CONCLUSION

OMNI® is budgetary efficient from a US payer perspective.

FP and EP2 prostanoid receptor agonist drugs and aqueous humor outflow devices for treating ocular hypertension and glaucoma

Prostaglandin (PG) receptors represent important druggable targets due to the many diverse actions of PGs in the body. From an ocular perspective, the discovery, development, and health agency approvals of prostaglandin F (FP) receptor agonists (FPAs) have revolutionized the medical treatment of ocular hypertension (OHT) and glaucoma. FPAs, such as latanoprost, travoprost, bimatoprost, and tafluprost, powerfully lower and control intraocular pressure (IOP), and became first-line therapeutics to treat this leading cause of blindness in the late 1990s to early 2000s. More recently, a latanoprost-nitric oxide (NO) donor conjugate, latanoprostene bunod, and a novel FP/EP3 receptor dual agonist, sepetaprost (ONO-9054 or DE-126), have also demonstrated robust IOP-reducing activity. Moreover, a selective non-PG prostanoid EP2 receptor agonist, omidenepag isopropyl (OMDI), was discovered, characterized, and has been approved in the United States, Japan and several other Asian countries for treating OHT/glaucoma. FPAs primarily enhance uveoscleral (UVSC) outflow of aqueous humor (AQH) to reduce IOP, but cause darkening of the iris and periorbital skin, uneven thickening and elongation of eyelashes, and deepening of the upper eyelid sulcus during chronic treatment. In contrast, OMDI lowers and controls IOP by activation of both the UVSC and trabecular meshwork outflow pathways, and it has a lower propensity to induce the aforementioned FPA-induced ocular side effects. Another means to address OHT is to physically promote the drainage of the AQH from the anterior chamber of the eye of patients with OHT/glaucoma. This has successfully been achieved by the recent approval and introduction of miniature devices into the anterior chamber by minimally invasive glaucoma surgeries. This review covers the three major aspects mentioned above to highlight the etiology of OHT/glaucoma, and the pharmacotherapeutics and devices that can be used to combat this blinding ocular disease.

The case for standalone micro-invasive glaucoma surgery: rethinking the role of surgery in the glaucoma treatment paradigm

PURPOSE OF REVIEW

To highlight progress in glaucoma therapy challenging the traditional medication-first approach and present evidence supporting early standalone surgery in the era of micro-invasive glaucoma surgery (MIGS).

RECENT FINDINGS

Medical therapy is limited by well documented poor adherence that compromises the quality of intraocular pressure reduction. Results from modern clinical trials demonstrate advantages of selective laser trabeculoplasty and MIGS procedures in terms of both IOP control and progression risk.

SUMMARY

The MIGS options for pseudophakic or precataractous patients are limited by regulatory rules that require the performance of some procedures only at the time of cataract surgery. These include the iStent/iStent Inject and the Hydrus implants. Nonbleb-forming procedures currently available for standalone use in eyes with mild-moderate primary open-angle glaucoma include gonioscopy-assisted transluminal trabeculotomy (which lowers IOP by 28-61% and medication use by 38-73% in various studies), trabecular ablation with the Trabectome (23-39% and 21-43%, respectively), excisional goniotomy with the Kahook Dual Blade (15-36% and 15-40%, respectively), ab interno canaloplasty (35% and 57%, respectively), and combined canaloplasty and trabeculotomy using the OMNI system (39-40% and 64-73%, respectively). For patients who would benefit from early standalone surgery, these procedures offer meaningful reductions in both IOP and medication burden.

Comparison of Safety and Efficacy of Hydrus and iStent Combined with Phacoemulsyfication in Open Angle Glaucoma Patients: 24-Month Follow-Up

The paper presents the results of a 24-month-long observation comparing the effectiveness and safety of two micro-invasive glaucoma surgery (MIGS) devices: Hydrus Microstent and iStent Trabecular Bypass in combination with cataract phacoemulsification in the treatment of open-angle glaucoma. We also analyzed the impact of preoperative factors on achieving surgical success in both surgical methods. The prospective, comparative, non-randomized study included 65 glaucoma surgeries. In 35 patients (53.8%), an iStent implant procedure was performed, while 30 patients (46.2%) underwent a Hydrus implant procedure. The demographic data was similar in both treatment groups. At 24 months after surgery, the mean IOP in the iStent group was 15.9 ± 3.0 mmHg and in the Hydrus group 16.2 ± 1.8 mmHg. The difference between the mean iStent vs Hydrus after two years of treatment was -0.3 (p = 0.683). At the 24 month follow-up, the average change in the number of antiglaucoma medications used was 71.7% in the iStent group and 79.6% in the Hydrus group. The difference in mean percentage change between groups was 7.9% in favor of Hydrus. Patients under the age of 70 may benefit from a greater risk reduction in the Hydrus group (HR = 0.81), while those over the age of 70 may benefit from a risk reduction in the iStent group (HR = 1.33). IOP cases with >18 mmHg before the surgery have a better chance of surgical success with the Hydrus method (HR = 0.28), and with IOP < 18 mmHg in the iStent group (HR = 1.93). Cases with more drugs (≥3 drugs) are more favorable in the Hydrus group (HR = 0.23), while those with a maximum of two drugs have a better prognosis in the iStent group (HR = 2.23). The most common postoperative complication was the presence of erythrocytes in the anterior chamber (AC), found in 40.0% of operated eyes in the Hydrus group. The profile of observed complications and significant improvement in visual acuity allows us to consider both implants as a safe way of treating patients with early or moderate glaucoma and co-existing cataracts.

Systematic Literature Review of Clinical, Economic, and Humanistic Outcomes Following Minimally Invasive Glaucoma Surgery or Selective Laser Trabeculoplasty for the Treatment of Open-Angle Glaucoma with or Without Cataract Extraction

Introduction

Selective laser trabeculoplasty (SLT) and minimally invasive glaucoma surgery (MIGS) are increasingly used options for mild-to-moderate open-angle glaucoma (OAG) care. While most MIGS devices are indicated for use in combination with cataract surgery only, with phacoemulsification playing a role in lowering IOP, newer technologies can also be used as standalone glaucoma surgery.

Methods

This systematic literature review (SLR) aimed to assess the clinical, economic, and humanistic outcomes of MIGS and SLT for the treatment of OAG and was conducted according to PRISMA guidelines. Studies that assessed MIGS or SLT in at least one treatment arm versus any other glaucoma treatment in adults with mild-to-moderate OAG were included. Clinical, humanistic (health-related quality of life [HRQoL] and patient burden), and economic data were extracted, and the methodological quality of included studies was evaluated.

Results

A total of 2720 articles were screened, and 81 publications were included. Fifty-eight reported clinical outcomes. The majority assessed iStent or iStent inject (n=41), followed by OMNI (n=9), gonioscopy-assisted transluminal trabeculotomy (GATT) or the Kahook Dual Blade (KDB) (n=7), Hydrus (n=6), SLT (n=5), Xen Gel Stent (n=2), PreserFlo (n=1), and iTrack (n=1). IOP reduction was observed across prospective studies, varying from -31% to -13.7% at month 6 and from -39% to -11.4% at year 1 versus baseline. Most adverse events were transient and non-serious. Limited humanistic and economic data were identified.

Conclusion

Given their established efficacy and safety, there is a rationale for wider use of MIGS in mild-to-moderate OAG. Of the MIGS devices, iStent and OMNI have the largest clinical evidence base supporting their sustained effectiveness.

Minimally Invasive Glaucoma Surgery: Safety of Individual Devices

Primary open-angle glaucoma progression in those already on maximal medical therapy has traditionally been treated with trabeculectomy, a surgical procedure that carries a high degree of morbidity. In the last few decades, significant advances have been made in the field of minimally invasive glaucoma surgery (MIGS) devices, which aim to defer or prevent trabeculectomy via less arduous surgical techniques in certain types of glaucoma. Although reviews have been published examining the efficacy of various MIGS techniques, no article synthesises the comparative safety of all available devices. We performed a literature review examining the safety of MIGS devices. Fifteen devices were included, variously attempting to increase aqueous outflow through the trabecular meshwork or the suprachoroidal space, shunting into the subconjunctival space, or reducing aqueous production through ciliary body ablation. Notably, the earliest product attempting to increase outflow to the suprachoroidal space, Alcon's CyPass Micro-Stent, was withdrawn from the market due to concerns regarding increased corneal endothelial cell loss at five years post-implantation. All other devices were described as well-tolerated, with the most common adverse effects including hyphaema, intraocular pressure spikes, and device migration or obstruction. MIGS devices are purported to be uniformly safe, and many studies report no statistically significant increased complications beyond those associated with cataract surgery alone. It is important to note, however, the generally poor quality of current studies, with a dearth of randomised, or even prospective, data, and a large proportion of studies funded by device producers.

Minimally Invasive Glaucoma Surgery in Primary Angle-Closure Glaucoma

Primary angle-closure glaucoma (PACG) is responsible for half of the glaucoma-related blindness worldwide. Cataract surgery with or without trabeculectomy has been considered to be the first-line treatment in eyes with medically uncontrolled PACG. While minimally invasive glaucoma surgery has become an important surgical approach for primary open-angle glaucoma, its indications and benefits in PACG are less clear. This review summarizes the efficacy and safety profile of minimally invasive glaucoma surgery in PACG to unfold new insights into the surgical management of PACG.

Laser trabeculoplasty for open-angle glaucoma and ocular hypertension

BACKGROUND

Open-angle glaucoma (OAG) is an important cause of blindness worldwide. Laser trabeculoplasty, a treatment modality, still does not have a clear position in the treatment sequence.

OBJECTIVES

To assess the effects of laser trabeculoplasty for treating OAG and ocular hypertension (OHT) when compared to medication, glaucoma surgery or no intervention. We also wished to compare the effectiveness of different laser trabeculoplasty technologies for treating OAG and OHT.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2021, Issue 10); Ovid MEDLINE; Ovid Embase; the ISRCTN registry; LILACS, ClinicalTrials.gov and the WHO ICTRP. The date of the search was 28 October 2021. We also contacted researchers in the field.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing laser trabeculoplasty with no intervention, with medical treatment, or with surgery in people with OAG or OHT. We also included trials comparing different types of laser trabeculoplasty technologies.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by Cochrane. Two authors screened search results and extracted data independently. We considered the following outcomes at 24 months: failure to control intraocular pressure (IOP), failure to stabilise visual field progression, failure to stabilise optic neuropathy progression, adverse effects, quality of life, and costs. We graded the 'certainty' of the evidence using GRADE.

MAIN RESULTS

We included 40 studies (5613 eyes of 4028 people) in this review. The majority of the studies were conducted in Europe and in the USA. Most of the studies were at risk of performance and/or detection bias as they were unmasked. None of the studies were judged as having low risk of bias for all domains. We did not identify any studies of laser trabeculoplasty alone versus no intervention. Laser trabeculoplasty versus medication Fourteen studies compared laser trabeculoplasty with medication in either people with primary OAG (7 studies) or primary or secondary OAG (7 studies); five of the 14 studies also included participants with OHT. Six studies used argon laser trabeculoplasty and eight studies used selective laser trabeculoplasty. There was considerable clinical and methodological diversity in these studies leading to statistical heterogeneity in results for the primary outcome "failure to control IOP" at 24 months.  Risk ratios (RRs) ranged from 0.43 in favour of laser trabeculoplasty to 1.87 in favour of medication (5 studies, I2 = 89%). Studies of argon laser compared with medication were more likely to show a beneficial effect compared with studies of selective laser (test for interaction P = 0.0001) but the argon laser studies were older and the medication comparator group in those studies may have been less effective. We considered this to be low-certainty evidence because the trials were at risk of bias (they were not masked) and there was unexplained heterogeneity. There was evidence from two studies (624 eyes) that argon laser treatment was associated with less failure to stabilise visual field progression compared with medication (7% versus 11%, RR 0.70, 95% CI 0.42 to 1.16) at 24 months and one further large recent study of selective laser also reported a reduced risk of failure at 48 months (17% versus 26%) RR 0.65, 95% CI 0.52 to 0.81, 1178 eyes). We judged this outcome as moderate-certainty evidence, downgrading for risk of bias. There was only very low-certainty evidence on optic neuropathy progression. Adverse effects were more commonly seen in the laser trabeculoplasty group including peripheral anterior synechiae (PAS) associated with argon laser (32% versus 26%, RR 11.74, 95% CI 5.94 to 23.22; 624 eyes; 2 RCTs; low-certainty evidence); 5% of participants treated with laser in three studies of selective laser group had early IOP spikes (moderate-certainty evidence). One UK-based study provided moderate-certainty evidence that laser trabeculoplasty was more cost-effective.  Laser trabeculoplasty versus trabeculectomy Three studies compared laser trabeculoplasty with trabeculectomy. All three studies enrolled participants with OAG (primary or secondary) and used argon laser. People receiving laser trabeculoplasty may have a higher risk of uncontrolled IOP at 24 months compared with people receiving trabeculectomy (16% versus 8%, RR 2.12, 95% CI 1.44 to 3.11; 901 eyes; 2 RCTs). We judged this to be low-certainty evidence because of risk of bias (trials were not masked) and there was inconsistency between the two trials (I2 = 68%). There was limited evidence on visual field progression suggesting a higher risk of failure with laser trabeculoplasty. There was no information on optic neuropathy progression, quality of life or costs. PAS formation and IOP spikes were not reported but in one study trabeculectomy was associated with an increased risk of cataract (RR 1.78, 95% CI 1.46 to 2.16) (very low-certainty evidence).

AUTHORS' CONCLUSIONS

Laser trabeculoplasty may work better than topical medication in slowing down the progression of open-angle glaucoma (rate of visual field loss) and may be similar to modern eye drops in controlling eye pressure at a lower cost. It is not associated with serious unwanted effects, particularly for the newer types of trabeculoplasty, such as selective laser trabeculoplasty.

Two-year outcomes of the MINIject drainage system for uncontrolled glaucoma from the STAR-I first-in-human trial

BACKGROUND/AIMS

The current study evaluates the efficacy and safety of the stand-alone implantation of the MINIject (iSTAR Medical, Wavre, Belgium) supraciliary, microinvasive glaucoma drainage device in patients with medically uncontrolled open-angle glaucoma.

METHODS

This prospective, multicentre, first-in-human, single-arm interventional study evaluated stand-alone, ab interno implantation in 25 patients of a 5 mm long uveoscleral device made of STAR biocompatible material, which is a soft, microporous, flexible silicone. The primary outcome was the reduction of intraocular pressure (IOP) at 6 months compared with baseline, and follow-up continued until 2 years for 21 patients. Secondary outcomes included success defined as diurnal IOP of ≤21 mmHg and >5 mmHg with an IOP reduction of 20% without (complete) or with/without (qualified) glaucoma medication.

RESULTS

Mean baseline IOP was 23.2±2.9 mmHg on 2.0±1.1 glaucoma medication ingredients and decreased to 13.8±3.5 mmHg (-40.7% reduction) on 1.0±1.3 medications 2 years after implantation. Complete success was achieved in 47.6% of patients (10/21) and qualified success in 100% of patients (21/21) at the 2-year follow-up. All patients achieved a 20% IOP reduction with 48% of patients medication-free. No serious ocular adverse events or additional glaucoma surgery were reported. Mean central endothelial cell density (ECD) mildly decreased from 2411 cells/mm2 (n=26) to 2341 cells/mm2 (n=21) at 24 months, which represents a 5% decrease for matched eyes. No patient had a ≥30% decrease in central ECD.

CONCLUSION

This first-in-human study on the stand-alone implantation of the MINIject supraciliary drainage system shows promising IOP-lowering results and medication reduction over 24 months with few adverse events.

TRIAL REGISTRATION NUMBER

NCT03193736.

Role of minimally invasive glaucoma surgery in the management of chronic open-angle glaucoma

To compare the safety and efficacy of phacoemulsification combined with ab-interno trabeculectomy (Trabectome) and phacoemulsification combined with I-Stent inject in patients with medically uncontrolled primary open-angle glaucoma (POAG). A retrospective comparative case series. 70 eyes of 66 patients completed 2 years follow up after these treatments performed in 2017–2018. 35 eyes of 33 patients underwent combined Phaco-Trabectome (PT); and 35 eyes of 33 patients underwent combined Phaco-I-Stent inject (Pi). Patient demographics and preoperative characteristics are comparable. A 20% drop in IOP was achieved in 27 eyes (77.14%) in PT group and 28 eyes (80%) in Pi group (p = 0.77). Success rate (target IOP achieved and maintained for 2 years) in advance glaucoma was 25% in PT group and 30.7% in Pi group (p = 0.90). In mild to moderate glaucoma, success rate was 85.71% in PT group and 90% in Pi group (p = 0.67). There was no significant difference between two groups with regards to mean reduction in glaucoma medications and complication rates. Trabectome and I-Stent combined with phacoemulsification are equally efficacious and safe for treating patients with medically uncontrolled mild and moderate primary open-angle glaucoma (POAG). However, they are not an effective treatment for patients with advanced glaucoma.

Parylene-C Microbore Tubing: A Simpler Shunt for Reducing Intraocular Pressure

OBJECTIVE

Current minimally-invasive glaucoma surgery (MIGS) devices promise to control elevated levels of intraocular pressure (IOP) while avoiding many of the downsides of traditional glaucoma surgery. However, there remains room for improvement in performance metrics, including drainage efficacy, device longevity, and time to implant, as outlined by benchmarks set forth by the Audacious Goals Initiative. We introduce a better shunt, which achieves similar or improved pre-clinical safety and efficacy outcomes to commercial MIGS devices, while reducing surgical profile and implantation time.

METHODS

We developed a parylene-based microbore glaucoma drainage device capable of modulating IOP via a minimally-invasive implantation procedure. We surgically implanted microbore tubing in five healthy New Zealand White rabbits and measured IOP levels biweekly using handheld applanation tonometry to assess device efficacy in lowering and maintaining IOP. After 6 weeks, the rabbits were euthanized and eyes were enucleated to evaluate inflammatory and histologic response to a foreign-body implant.

RESULTS

This device is the only one that fulfills the 10-minute benchmark for implantation time compared to other commercial MIGS devices. In 4 of 5 animals implanted, post-op IOP in the experimental eye dropped by an average of 16.17%. Histopathologic evaluation revealed localized evidence of minor inflammatory reaction and tissue irritation, as well as minimal fibrosis along the tube-tissue interface.

CONCLUSION AND SIGNIFICANCE

Based on these findings, this device stands as a promising platform to lowering IOP, particularly in patients with mild to moderate glaucoma requiring no need for cataract intervention, without eliciting a severe biological response.

The Hydrus Microstent in Pseudophakic Patients With Medically Refractory Open-angle Glaucoma

PURPOSE

Minimally invasive glaucoma surgery (MIGS) is an emerging therapy for glaucoma. The Hydrus Microstent is a MIGS device that stents Schlemm's canal, thereby increasing aqueous drainage and lowering intraocular pressure (IOP). This article describes the use of the microstent in pseudophakic patients with medically refractory glaucoma, a patient population undocumented in the current literature.

PATIENTS AND METHODS

We present a retrospective case series of 11 pseudophakic eyes using 3 or more pressure lowering medications daily for open-angle glaucoma who underwent Hydrus Microstent insertion. Patients were followed up at 1, 3, 6, 12, 24, 36, 48, and 60 months postoperatively and assessed for reductions in IOP and medication burden.

RESULTS

At intervals 12 and 24 months, medication burden reduced by 75.6% at both junctures, and IOP reduced by 43.8% and 34.1%. Complications included 4 hyphaemas and 1 corneal epithelial defect, each of which resolved.

DISCUSSION

This case series demonstrated effective pressure and medication reduction in medically refractory open-angle glaucoma patients using the Hydrus Microstent. Use of this device in this population is thus far undocumented in the literature and may represent an optimal therapeutic modality in the future.

Cost-utility analysis of trabecular micro-bypass stents (TBS) in patients with mild-to-moderate open-angle Glaucoma in Italy

BACKGROUND

Glaucoma is a disease characterized by progressive damage of the optic nerve. Several therapeutic options are available to lower intraocular pressure (IOP). In primary open-angle glaucoma (POAG) patients with inadequate IOP control (or controlled with multiple medical therapies or for whom medical therapy is contraindicated), the implantation of micro-invasive glaucoma surgery devices (MIGS) and concomitant cataract surgery has proved to be more effective in reducing intraocular pressure (IOP), as compared to cataract surgery alone. The objective of this study was to assess the cost-effectiveness of iStent inject® device with concurrent cataract surgery vs. cataract surgery alone, in patients with mild-to-moderate POAG, adopting the Italian National Health Service (NHS) perspective.

METHODS

Simulation of outcomes and costs was undertaken using a Markov model with 4 health states and one-month cycles, that is used to simulate the prognosis of these patients. Efficacy data were obtained from the randomized clinical trial (RCT). A lifetime horizon was adopted in the analysis. A discount rate of 3.5% was applied to both costs and effects. The Italian National Healthcare Service (NHS) perspective was considered, therefore only healthcare direct costs (acquisition of main interventions and subsequent procedures; medications; monitoring and follow-up; adverse events). Model robustness was tested through sensitivity analyses.

RESULTS

Results of the base-case analysis showed that the total lifetime costs were higher in the iStent inject® + concurrent cataract surgery, compared with the cataract surgery alone group (€8368.51 vs. €7134.71 respectively). iStent inject® + concurrent cataract surgery was cost-effective vs. cataract surgery alone, with an incremental cost-effectiveness ratio of €13,037.01 per quality-adjusted life year (QALY) gained. Both one-way deterministic and probabilistic sensitivity analyses confirmed robustness of base-case results. The cost-effectiveness accessibility curve (CEAC) showed that iStent inject® + cataract surgery would have a 98% probability of being cost-effective, compared to cataract surgery alone, when the willingness to pay (WTP) is equal to €50,000 per QALY gained.

CONCLUSIONS

The results of the cost-utility analysis confirm that iStent inject® + cataract surgery is a cost-effective option for the treatment of patients affected by mild-to-moderate POAG, compared with cataract surgery alone, when evaluated from the Italian NHS perspective.

Minimally Invasive Glaucoma Surgery: A Critical Appraisal of the Literature

Micro- or minimally invasive glaucoma surgeries (MIGS) have been the latest addition to the glaucoma surgical treatment paradigm. This term refers not to a single surgery, but rather to a group of distinct procedures and devices that aim to decrease intraocular pressure. Broadly, MIGS can be categorized into surgeries that increase the trabecular outflow [Trabectome, iStent (first and second generations), Hydrus microstent, Kahook Dual Blade and gonioscopy-assisted transluminal trabeculotomy], surgeries that increase suprachoroidal outflow (Cypass microstent and iStent Supra), and conjunctival bleb-forming procedures (Xen gel stent and InnFocus microshunt). Compared to traditional glaucoma surgeries, such as trabeculectomy and glaucoma drainage device implantation (Ahmed, Baerveldt, and Molteno valves), MIGS are touted to have less severe complications and shorter surgical time. MIGS represent an evolving field, and the efficacy and complications of each procedure should be considered independently, giving more importance to high-quality and longer-term studies.

Modeling the effects of glaucoma surgery on intraocular pressure

Minimally invasive glaucoma surgeries (MIGS) offer an effective way to lower intraocular pressure without inducing extensive trauma to the anterior segment. In order to predict their efficacy, an analytical model of the conventional aqueous humor outflow pathway is developed using a resistor network. The model describes outflow through the normal eye and allows for the effects of geometric changes in the outflow pathway as IOP changes. By selectively removing these resistors, the model can be used to examine and predict the outcomes of several surgical procedures currently used to treat glaucoma. Treatments examined include traditional trabeculectomy, several ab interno methods for trabeculotomy and trabeculectomy, as well as recently developed trabecular stents that bypass the trabecular meshwork and dilate Schlemm canal. The model's predictions for the efficacy of these procedures generally matched well with the efficacy determined in experimental studies, although it tended to somewhat overestimate the efficacy of these procedures. Matching the model to experimental data indicated that a partial trabeculotomy substantially increases flow to collector channels within that region and approximately 1.5 clock hours past the ends of the trabeculotomized region. Similarly, trabecular bypass stents substantially increase flow to collector channels up to 1.5 clock hours past the open ends of the stent. The resistor model we have developed can be used to predict the efficacy of a variety of MIGS procedures. Circumferential flow in Schlemm canal extends the efficacy of MIGS, but this effect is limited to a few clock hours.

Exploiting biomaterial approaches to manufacture an artificial trabecular meshwork: A progress report

Glaucoma is the second leading cause of irreversible blindness worldwide. Glaucoma is a progressive optic neuropathy in which permanent loss of peripheral vision results from neurodegeneration in the optic nerve head. The trabecular meshwork is responsible for regulating intraocular pressure, which to date, is the only modifiable risk factor associated with the development of glaucoma. Lowering intraocular pressure reduces glaucoma progression and current surgical approaches for glaucoma attempt to reduce outflow resistance through the trabecular meshwork. Many surgical approaches use minimally invasive glaucoma surgeries (MIGS) to control glaucoma. In this progress report, biomaterials currently employed to treat glaucoma, such as MIGS, and the issues associated with them are described. The report also discusses innovative biofabrication approaches that aim to revolutionise glaucoma treatment through tissue engineering and regenerative medicine (TERM). At present, there are very few applications targeted towards TM engineering in vivo, with a great proportion of these biomaterial structures being developed for in vitro model use. This is a consequence of the many anatomical and physiological attributes that must be considered when designing a TERM device for microscopic tissues, such as the trabecular meshwork. Ongoing advancements in TERM research from multi-disciplinary teams should lead to the development of a state-of-the-art device to restore trabecular meshwork function and provide a bio-engineering solution to improve patient outcomes.

Real-world efficacy of the Hydrus microstent in Black and Afro-Latinx patients with glaucoma: a retrospective study

Purpose:

The purpose was to determine the real-world efficacy of phacoemulsification cataract surgery and Hydrus microstent in Black and Afro-Latinx patients with glaucoma.

Methods:

A retrospective noncomparative single-center study of 76 Black and Afro-Latinx patients with glaucoma who underwent phacoemulsification cataract surgery and Hydrus microstent placement for treatment of glaucoma at single practice. Investigated parameters were intraocular pressure (IOP), number of medications, mean deviation on visual field test, and visual acuity. Patients were also subgrouped into mild, moderate, and advance glaucoma for further analysis.

Results:

We reviewed a total of 76 patients who had 6 months of follow up in the study. The mean number of medications decreased significantly from 2.6 ± 1.5 preoperatively to 0.72 ± 1.4 in 6 months (p < 0.0010), while IOP decreased from 14.7 ± 3.7 to 13.9 ± 4.3 (p = 0.25). At 6 months, 55 patients (74%) of all patients were medication free (n = 27, 84.4% mild glaucoma; n = 17, 70.8% moderate glaucoma; n = 10, 50% advance glaucoma). There was significant improvement in visual acuity (p < 0.00010) and stabilization of mean deviation on visual field test (baseline −9.2; 6 months −9.1; p = 0.22). The most common adverse effect was a transient IOP spike and transient corneal edema (n = 6, 7.9%; n = 6, 7.9%, respectively) with spontaneous resolution in all cases. No sight-threatening complications were reported at 6 months.

Conclusion/clinical relevance:

This 6-month retrospective study demonstrated the efficacy of phacoemulsification cataract surgery and Hydrus microstent in reducing the medication burden while maintaining lower IOP in Black and Afro-Latinx patients with glaucoma.

Minimally Invasive Surgery in Mild-to-Moderate Glaucoma Patients in Italy: Is It Time to Change?

Medical therapy is the first treatment choice for most patients with glaucoma; however, in a relevant proportion of patients, intraocular pressure (IOP) reduction is achieved with multi-therapy and/or high therapeutic doses. Conventional surgery is the standard alternative to medical therapy when this is not effective or not tolerated. Recently, selective laser trabeculoplasty (SLT) has been advocated as first-line therapy, and "minimally invasive glaucoma surgery" (MIGS) has been developed as safer and less traumatic surgical intervention for patients with glaucoma. Schlemm's canal surgery has emerged as one of the approaches with the most favorable risk-benefit profile for glaucoma patients in need of cataract surgery. However, despite the promising results, use of MIGS in Italy has been extremely low. We aimed to investigate the reasons of the lower-than-expected use of Schlemm's canal-based MIGS devices in Italy, share our perspective on their potential place in therapy, and give practical suggestions to improve the management of glaucoma patients.

Visual outcomes of combined cataract surgery and minimally invasive glaucoma surgery

Minimally invasive glaucoma surgery (MIGS) has become a reliable standard of care for the treatment of glaucoma when combined with cataract surgery. This review describes the MIGS procedures currently combined with and without cataract surgery with a focus on visual outcomes based on the literature and the experience of the ASCRS Glaucoma Clinical Committee.

XEN® Gel Stent: A Comprehensive Review on Its Use as a Treatment Option for Refractory Glaucoma

The XEN Gel Microstent is a subconjunctival microinvasive glaucoma surgical device developed with the aim of improving the predictability and safety profile of bleb-forming glaucoma surgical procedures. The stent is a hydrophilic tube composed of a porcine gel cross-linked with glutaraldehyde with good stability and biocompatibility with minimal tissue reaction. This device has demonstrated promising outcomes with fewer risks compared to traditional surgeries. The aim of the review is to present early studies on different designs of the XEN Gel Stent, to summarize different surgical techniques of implantation and to analyze more comprehensively the results, complications and rates of needling of the commercially available device (Xen 45). The review will address separately special cases (PXG, UVG, ICE, congenital glaucoma) and describe small series and case reports.

Personalising surgical treatments for glaucoma patients

Surgical treatments for glaucoma have relied for decades on traditional filtering surgery such as trabeculectomy and, in more challenging cases, tubes. Antifibrotics were introduced to improve surgical success in patients at increased risk of failure but have been shown to be linked to a greater incidence of complications, some being potentially vision-threatening. As our understanding of glaucoma and its early diagnosis have improved, a more individualised management has been suggested. Recently the term "precision medicine" has emerged as a new concept of an individualised approach to disease management incorporating a wide range of individual data in the choice of therapeutic modalities. For glaucoma surgery, this involves evaluation of the right timing, individual risk factors, targeting the correct anatomical and functional outflow pathways and appropriate prevention of scarring. As a consequence, there is an obvious need for better knowledge of anatomical and functional pathways and for more individualised surgical approaches with new, less invasive and safer techniques allowing for earlier intervention. With the recent advent of minimally invasive glaucoma surgery (MIGS) a large number of novel devices have been introduced targeting potential new sites of the outflow pathway for lowering intraocular pressure (IOP). Their popularity is growing in view of the relative surgical simplicity and apparent lack of serious side effects. However, these new surgical techniques are still in an era of early experiences, short follow-up and lack of evidence of their superiority in safety and cost-effectiveness over the traditional methods. Each year several new devices are introduced while others are withdrawn from the market. Glaucoma continues to be the primary cause of irreversible blindness worldwide and access to safe and efficacious treatment is a serious problem, particularly in the emerging world where the burden of glaucoma-related blindness is important and concerning. Early diagnosis, individualised treatment and, very importantly, safe surgical management should be the hallmarks of glaucoma treatment. However, there is still need for a better understanding of the disease, its onset and progression, the functional and structural elements of the outflow pathways in relation to the new devices as well as their long-term IOP-lowering efficacy and safety. This review discusses current knowledge and the future need for personalised glaucoma surgery.

Minimally Invasive Glaucoma Surgery: Where Is the Evidence?

PURPOSE

The last decade has witnessed an unprecedented growth in glaucoma treatment options through the introduction of minimally invasive glaucoma surgeries (MIGS). The aim of the present review is to provide an understanding of the currently available MIGS and to examine what data are currently available to guide treatment choice.

DESIGN

Meta-analysis and systematic review of randomized and non-randomized control trials.

METHODS

Out of 2567 articles identified, a total of 77 articles were retained for analysis, including 28 comparative studies and 12 randomized control trials. Overall, 7570 eyes were included. When data permitted, the weighted mean difference in intraocular pressure reduction was calculated for comparison purposes.

RESULTS

Weighted mean intraocular pressure reductions from all analyzed studies were: 15.3% (iStent), 29.1% (iStent inject), 36.2% (ab interno canaloplasty), 34.4% (Hydrus), 36.5% (gonioscopically-assisted transluminal trabeculotomy), 24.0% (trabectome), 25.1% (Kahook dual blade), 30.2% (Cypass), 38.8% (XEN), and 50.0% (Preserflo).

CONCLUSIONS

One of the advantages of the heterogenous range of available MIGS options is the chance to tailor therapy in an individualized manner. However, high-quality data are required to make this choice more than an educated guess. Overall, this review confirms the efficiency of assessed MIGS compared with standalone phacoemulsification, but it highlights that only few studies compare different MIGS techniques and even fewer assess MIGS against criterion standard treatments. Current evidence, while non-negligible, is mostly limited to heterogenous nonrandomized studies and uncontrolled retrospective comparisons, with few quality randomized control trials. We suggest that future research should be comparative and include relevant comparators, standardized to report key outcome features, long-term to assess sustainability and late complications, and ideally randomized.

Prospective Studies of Minimally Invasive Glaucoma Surgeries: Systematic Review and Quality Assessment

Glaucoma is a common blinding disease; while there is no cure, effective treatments include medications, laser, and incisional surgery. There is significant interest from patients and doctors to develop safer surgical options throughout the spectrum of disease, to minimize treatment burden in mild glaucoma patients and to minimize risk of complications in patients needing more aggressive treatment. Surgical procedures called Minimally or Micro-Invasive Glaucoma Surgery (MIGS) are growing in popularity. Eighty-seven prospective studies on MIGS were identified and assessed for quality. Most (74%) did not have a control group. Twelve of the highest quality were reviewed. MIGS procedures appeared to have fewer complications, and lowered intraocular pressure, and reduced medication use. Studies were limited by small sample size, narrow spectrum of glaucomatous disease, and/or conflicts of interest. There is a need for high quality, independently funded and performed, comparative studies on the MIGS to help make treatment decisions.

The Efficacy and Safety of High-Frequency Deep Sclerotomy in Treatment of Chronic Open-Angle Glaucoma Patients

Purpose

Highlights the high-frequency deep sclerotomy as a competing ab interno surgery in open-angle glaucoma patients and evaluates the efficacy of high-frequency deep sclerotomy in lowering IOP of chronic open-angle glaucoma patients, in addition to the evaluation of the safety of the procedure on the corneal endothelium.

Design

A prospective study. It was performed in the Research Institute of Ophthalmology, Cairo.

Participants

43 eyes were enrolled for the study. All eyes were diagnosed with chronic open-angle glaucoma.

Methods

The procedure was performed using the abee® glaucoma tip of Oertli phacoemulsification machine (OS3, Switzerland) and goniolens performing nasal six pockets penetrating 1 mm deep into the trabecular meshwork and Schlemm's canal. Patients were followed up regarding vision and intraocular pressure (IOP) for 9 months. Endothelial cell count and coefficient of variation were calculated using specular microscopy preoperatively and 9 months postoperatively.

Results

The mean preoperative IOP was 31.4 ± 4.71 mmHg (range: 22 to 42 mmHg). All patients were followed up for nine months. The mean IOP was 19.06 ± 1.907 mmHg (range: 15 to 26 mmHg) by the end of the study. The reduction across the follow-ups was statistically significant (P < 0.0001). The percentage of total success was 90.7% (39 eyes). Four eyes (9.3%) had IOP > 21 (failed) after surgery and continued on antiglaucoma therapy.

Conclusion

High-frequency deep sclerotomy is a safe and promising minimally invasive procedure which successfully achieves a lower IOP for chronic open-angle glaucoma patients, but not adequate for advanced glaucoma patients. This trial is registered with PACTR201910823824561.

Hydrus microstent implantation for surgical management of glaucoma: a review of design, efficacy and safety

With the advent of microinvasive glaucoma surgery (MIGS), the spectrum of modalities available to manage patients with this chronic and heterogeneous condition has broadened. Despite its novelty however, there has been a rapid evolution in the development of a multitude of devices, each targeting a structure along the aqueous drainage pathway. A growing body of evidence has demonstrated IOP and medication burden reduction, and a more favorable safety profile with MIGS procedures in contrast to traditional incisional surgeries. Among the array of MIGS, the Hydrus® Microstent (Ivantis, Inc., Irvine, CA) is a recent FDA approved device, designed to bypass the trabecular meshwork and provide a scaffold for Schlemm’s canal. The objective of this article is to review the Hydrus from conception to clinical use, and present data on its efficacy and safety to date. The available literature has shown promise, however inherent to all novel devices, only long-term monitoring will ensure sustained IOP control and an acceptable safety profile. Surgical advancements in glaucoma have revolutionized the field, and continued research and development will establish these approaches in clinical treatment algorithms.

Translating Minimally Invasive Glaucoma Surgery Devices

Glaucoma is the leading cause of irreversible blindness with over 70 million people affected worldwide. The surgical management of glaucoma aims to lower intraocular pressure by increasing aqueous outflow facility. The latest manufacturing techniques have allowed for the development of a number of novel implantable devices to improve safety and outcomes of glaucoma surgery. These are collectively referred to as minimally invasive glaucoma surgery (MIGS) devices and are among the smallest devices implanted in the human body. This review discusses the design criterion and constraints as well as the user requirements for MIGS devices. We review how recent devices have attempted to meet these challenges and give our opinion as to the necessary characteristics for the development of future devices.

A First-in-Human Study of the Efficacy and Safety of MINIject in Patients with Medically Uncontrolled Open-Angle Glaucoma (STAR-I)

PURPOSE

To describe the safety and efficacy of a novel, supraciliary, microinvasive glaucoma surgery drainage system, MINIject (iSTAR Medical, Wavre, Belgium), in the study.

DESIGN

Prospective, multicenter, interventional, single-arm trial.

PARTICIPANTS

Twenty-six patients with primary open-angle glaucoma uncontrolled with 1 or more intraocular pressure (IOP)-lowering medications.

METHODS

Using an ab interno approach, 25 eyes were implanted successfully in a stand-alone procedure with a 5-mm long device made of biocompatible STAR material, which is soft and flexible silicone in a microporous, network design. Intraocular pressure, medication use, and other ocular parameters were evaluated before surgery, 1 day, 1 and 2 weeks, and 1, 3, and 6 months after surgery.

MAIN OUTCOME MEASURES

Intraocular pressure reduction at 6 months compared with baseline analyzed using a paired t test. Safety evaluation entailed tabulation of the nature and frequency of adverse events.

RESULTS

Mean baseline diurnal IOP was 23.2 mmHg (standard error, 0.6 mmHg) using a mean ± standard deviation of 2.0±1.1 IOP-lowering medication classes. During the 6-month follow-up period, mean IOP ranged from 10.0-16.3 mmHg (mean reductions, 6.9-13.2 mmHg or 31.0%-56.8%). Six months after surgery, mean diurnal IOP was 14.2 mmHg (standard error, 0.9 mmHg), equivalent to a reduction of 9.0 mmHg or 39.1% (P < 0.0001). The mean ± standard deviation number of IOP-lowering medications was 0.3±0.7. Of 24 patients seen at 6-month follow-up, 21 (87.5%) were medication-free and 23 (95.8%) achieved a minimum 20% IOP reduction from baseline. There were no serious adverse events related to the device or procedure, and no additional glaucoma surgery was required. Frequently reported events included anterior chamber inflammation (n = 8), IOP elevation (n = 6), of which 1 event was an IOP spike per protocol, visual acuity reduction (n = 3), and hyphema (n = 3), all of which resolved. There was no change to mean central or peripheral corneal endothelial cell density. No device-related adverse events were reported.

CONCLUSIONS

The MINIject glaucoma drainage system significantly lowered IOP and eliminated the need for medication in most patients 6 months after surgery when implanted in a standalone procedure. There were no serious ocular adverse events.

A Prospective Randomized Trial Comparing Hydrus and iStent Microinvasive Glaucoma Surgery Implants for Standalone Treatment of Open-Angle Glaucoma: The COMPARE Study

PURPOSE

To compare the efficacy of different microinvasive glaucoma surgery (MIGS) devices for reducing intraocular pressure (IOP) and medications in open-angle glaucoma (OAG).

DESIGN

Prospective, multicenter, randomized clinical trial.

PARTICIPANTS

One hundred fifty-two eyes from 152 patients aged 45 to 84 years with OAG, Shaffer angle grade III-IV, best-corrected visual acuity (BCVA) 20/30 or better, and IOP 23 to 39 mmHg after washout of all hypotensive medications. Eyes with secondary glaucoma other than pseudoexfoliative or pigmentary glaucoma, angle closure, previous incisional glaucoma surgery, or any significant ocular pathology other than glaucoma were excluded.

INTERVENTION

Study eyes were randomized 1:1 to standalone MIGS consisting of either 1 Hydrus Microstent (Ivantis, Inc, Irvine, CA) or 2 iStent Trabecular Micro Bypass devices (Glaukos Inc, San Clemente, CA). Follow-up was performed 1 day, 1 week, and 1, 3, 6, and 12 months postoperatively.

MAIN OUTCOME MEASURES

Within-group and between-group differences in IOP and medications at 12 months and complete surgical success defined as freedom from repeat glaucoma surgery, IOP 18 mmHg or less, and no glaucoma medications. Safety measures included the frequency of surgical complications, changes in visual acuity, slit-lamp findings, and adverse events.

RESULTS

Study groups were well matched for baseline demographics, glaucoma status, medication use, and baseline IOP. Twelve-month follow-up was completed in 148 of 152 randomized subjects (97.3%). At 12 months, the Hydrus had a greater rate of complete surgical success (P < 0.001) and reduced medication use (difference = -0.6 medications, P = 0.004). More Hydrus subjects were medication free at 12 months (difference = 22.6% P = 0.0057). Secondary glaucoma surgery was performed in 2 eyes in the 2-iStent group (3.9%) and in none of the Hydrus eyes. Two eyes in the Hydrus group and 1 in the 2-iStent group had BCVA loss of ≥2 lines.

CONCLUSION

Standalone MIGS in OAG with the Hydrus resulted in a higher surgical success rate and fewer medications compared with the 2-iStent procedure. The 2 MIGS devices have similar safety profiles.

Twenty-Four-Hour Contact Lens Sensor Monitoring of Aqueous Humor Dynamics in Surgically or Medically Treated Glaucoma Patients

Aim

This study assessed the 24 h circadian rhythm of intraocular pressure (IOP) using a contact lens sensor in three groups of patients with open-angle glaucoma.

Methods

This study was a monocentric, cross-sectional, nonrandomized, prospective, pilot study. Eighty-nine patients were enrolled: 29 patients previously underwent an Ex-PRESS mini glaucoma device procedure (Group 1), 28 patients previously underwent Hydrus microstent implantation (Group 2), and 32 patients were currently being treated medically for primary open-angle glaucoma (Group 3). Circadian rhythm patterns were considered with five circadian indicators: fluctuation ranges, maximum, minimum, acrophase (time of peak value), and bathyphase (time of trough value). A two-tailed Mann–Whitney U-test was used to evaluate differences between groups.

Results

All subjects exhibited a circadian rhythm and a nocturnal pattern. The signal fluctuation range was significantly smaller in the surgical groups than in the medically treated group (Group 1 vs. Group 3, p=0.003; Group 2 vs. Group 3, p=0.010). Subjects who underwent the Ex-PRESS procedure (Group 1) exhibited significant differences compared with the drug therapy group (Group 3) with regard to the minimum value (p=0.015), acrophase (p=0.009), and bathyphase (p=0.002). The other circadian indicators were not significantly different among groups.

Conclusions

Patients who underwent IOP-lowering surgery had an intrinsic nyctohemeral rhythm. Both surgical procedures, Ex-PRESS and Hydrus, were associated with smaller signal fluctuations compared with medical treatment.

The Role of Minimally Invasive Glaucoma Surgery Devices in the Management of Glaucoma

SIGNIFICANCE

Noncompliance is a problem affecting glaucoma patients. Approaches to improve adherence include the use of drug-delivery systems and safer forms of surgery. Minimally invasive glaucoma surgery (MIGS) has reduced complications, particularly in combination with cataract surgery, and with its good intraocular pressure (IOP) reduction may reduce or eliminate glaucoma medications.Glaucoma is a progressive disease and a leading cause of irreversible blindness. Elevated IOP is the most important risk factor, but effective medical management is dependent on patient adherence. This review summarizes the adherence problem in glaucoma and the efforts, including MIGS, to provide effective IOP control that is not dependent on patient compliance.The current understanding of patient adherence to pharmacological treatment of glaucoma is discussed including the challenges facing glaucoma patients. Historical approaches to providing IOP control in a sustained and reliable way are presented culminating in a review of the burgeoning use of MIGS devices.It is estimated that, in the United States, 27% of prescriptions written, across all medications, are not filled or are filled but not taken. For ocular hypotensive medications, even when filled, a large percentage (which varies widely by study) are not instilled as prescribed. To address this problem, methods for sustained drug delivery have been and continue to be developed, as well as surgical and laser approaches. Most recently, MIGS devices have gained popularity because of the ease of implantation during cataract surgery, favorable safety profile, and the possibility for effective and long-lasting IOP lowering, as well as the reduction or elimination of need for IOP-lowering medication.Poor adherence to treatment is relatively common among glaucoma patients and is associated with progression of disease. Recommending MIGS implantation during cataract surgery may offer optometrists a valuable treatment option in managing glaucoma patients, particularly where good adherence is in doubt.

Evolution of Glaucoma Surgery in the Last 25 Years

Glaucoma is a chronic neurodegenerative optic nerve disease. Treatment is intended to prevent the development and progression of optic nerve damage by lowering intraocular pressure (IOP). Current therapy options include topical/systemic drugs that increase aqueous humor outflow or decrease its production, laser therapy that targets the trabecular meshwork and ciliary body, and incisional surgery. Trabeculectomy as well as glaucoma drainage devices are often performed, given their high efficacy in lowering IOP. However, the significant risk profile with potential sight-threatening complications has motivated glaucoma experts to create alternative surgeries to treat glaucoma. Minimally invasive glaucoma surgery (MIGS) is defined by: micro-invasive approach, minimal tissue trauma, high safety profile, and rapid recovery. The new devices might promote an earlier transition from medical/laser therapy to surgery, and therefore decrease the side effects associated with long-term use of topical medications as well as deal with the limited adherence of patients to their regimens. This review presents the surgical options available for glaucoma patients and their evolution over the past 25 years.

"Minimally Invasive Glaucoma Surgery (MIGS) Is a Poor Substitute for Trabeculectomy"-The Great Debate

Surgical treatment for glaucoma has undergone a dramatic change over the last decade. Trabeculectomy has been the main surgical procedure worldwide for almost 50 years. However, there is a growth in development of new novel devices and surgical techniques designed to lower intraocular pressure in a less invasive fashion. The term minimally invasive glaucoma surgery (MIGS) has been coined and is the subject of investment, debate and, increasingly, research. The position of MIGS in the glaucoma treatment paradigm is yet to be clearly defined and its ability to replace conventional filtration surgery remains debatable. In this paper two glaucoma specialists were invited to debate the motion that "MIGS is a poor substitute for trabeculectomy".

Systematic Literature Review of Clinical and Economic Outcomes of Micro-Invasive Glaucoma Surgery (MIGS) in Primary Open-Angle Glaucoma

INTRODUCTION

Primary open-angle glaucoma is estimated to affect 3% of the population aged 40-80 years. Trabeculectomy is considered the gold standard in surgical management of glaucoma; however, it is a technically complex procedure that may result in a range of adverse outcomes. Device-augmented, minimally invasive procedures (micro-invasive glaucoma surgeries, MIGS) have been developed aiming for safer and less invasive intraocular pressure (IOP) reduction compared with traditional surgery.

METHODS

This paper presents results from a systematic literature review conducted in accordance with National Institute for Health and Care Excellence requirements for the Medical Technology Evaluation Programme via multiple databases from 2005 to 2016. For clinical outcomes, randomized clinical trials (RCTs) comparing MIGS with trabeculectomy or other therapies, observational studies, and other non-RCTs were included. Clinical outcomes reviewed were the change from baseline in mean IOP levels and change in topical glaucoma medication. Safety was assessed by reported harm and adverse events. For economic evidence, trials on cost-effectiveness, cost-utility, cost-benefit, cost-consequences, cost-minimization, cost of illness, and specific procedure costs were included. Risk of bias was assessed for clinical studies using the Cochrane Risk of Bias tool.

RESULTS

A total of nine RCTs (seven iStents®, one Hydrus®, and one CyPass®), seven non-RCTs (three iStent®, three CyPass®, and one Hydrus®), and 23 economic studies were analyzed. While various forms of trabeculectomy can achieve postoperative IOP of between 11.0 and 13.0 mmHg, MIGS devices described in this review were typically associated with higher postoperative IOP levels. In addition, MIGS devices may result in increased hypotony rates or bleb needling in subconjunctival placed devices, requiring additional medical resources to manage. There is limited available evidence on the cost-effectiveness of MIGS and therefore it remains unclear whether the cost of using MIGS is outweighed by cost savings through decreased medication and need for further interventions.

CONCLUSION

Larger randomized trials and real-world observational studies are needed for MIGS devices to better assess clinical and economic effectiveness. Given the shortage of published data and increasing use of such procedures, living systematic reviews may help to provide ongoing and timely evidence-based direction for clinicians and decision makers. This review highlights the current unmet need for treatments that are easy to implement and reduce long-term IOP levels without increasing postoperative aftercare and cost.

FUNDING

Santen GmbH, Germany.

Complications of micro-invasive glaucoma surgery

PURPOSE OF REVIEW

Micro-invasive glaucoma surgery (MIGS) is gaining favor with both comprehensive ophthalmologists and glaucoma specialists due in part to its improved safety profile when compared to traditional incisional glaucoma surgery. Despite a micro-invasive approach and minimal induced tissue trauma, each MIGS procedure is associated with unique complications. The present article summarizes evidence from the 2016 to 2017 review period regarding the safety profiles of Schlemm's canal-based, suprachoroidal, and subconjunctival microstents.

RECENT FINDINGS

Ab-interno microstents are subject to intraoperative malpositioning, which can result in luminal obstruction and decreased efficacy. Acutely elevated intraocular pressure (IOP) has been observed with the iStent (Glaukos Corp., Laguna Hills, CA, USA; 2-4.3%), Hydrus Microstent (Ivantis Inc., Irvine, CA, USA; 6%), Cypass Microstent (Alcon, Fort Worth, TX, USA; 3-10.8%), and Xen Gel Stent (Allergan Plc, Dublin, Ireland; 21.5%). Meanwhile, most cases of hypotony (IOP < 6 mmHg) occurred within the first postoperative month, resolved with conservative treatment and without further surgical intervention, and were not associated with vision-threatening sequelae.

SUMMARY

Interest in MIGS continues to grow as these procedures allow surgeons to intervene earlier in the disease course for patients with milder stages of glaucoma. Complications associated with MIGS, albeit infrequent and mostly transient, do occur despite a less invasive approach than trabeculectomy and tube shunt surgery.

Selective laser trabeculoplasty: past, present, and future

Over the past two decades, selective laser trabeculoplasty (SLT) has increasingly become an established laser treatment used to lower intraocular pressure in open-angle glaucoma and ocular hypertensive patients. In this review we trace the origins of SLT from previous argon laser trabeculoplasty and review the current role it has in clinical practice. We outline future directions of SLT research and introduce emerging technologies that are further developing this intervention in the treatment paradigm of glaucoma.