Microinvasive Glaucoma Surgery Procedures Research Articles

Comparing Traditional and Newer Glaucoma Procedures by Physician Experience and Practice Location in the United States.

Analysis of CMS Physician Payment data found that physician certification year, degree of urbanization, and estimated income by zip code were significant in predicting the proportion of traditional glaucoma procedures performed by each provider in the United States. The prevalence of microinvasive glaucoma surgery (MIGS) compared to traditional procedures has been increasing in glaucoma management. It is important to understand whether the uptake of new glaucoma procedures is associated with aspects of the physician practice. In this cross-sectional study, data on glaucoma procedure distribution, degree of urbanization and physician certification in the United States were extracted from the 2019 Centers for Medicare & Medicaid Services (CMS) Physician Payment and American Board of Ophthalmology databases. The distribution of traditional and MIGS procedure numbers for metropolitan versus non-metropolitan providers were visualized with boxplots and statistically compared using Mann-Whitney U tests. We used two-dimensional histograms and regression analyses to assess the relationship between certification year and volume of traditional versus MIGS procedures. A multivariable linear regression model was created using certification year, rural-urban commuting area (RUCA) code, and estimated income by practice zip code to predict the number and proportion of each type of glaucoma procedure. This study included 2625 providers from the CMS physician payment data who performed only traditional procedures (n=370), MIGS procedures (n=1727), or both procedure types (n=528) in 2019. The median number of MIGS procedures performed by each provider was greater in non-metropolitan areas (31 vs. 29, P=0.015) while the proportion of traditional procedures performed by each provider was greater in metropolitan areas (0.24 vs. 0.08, P<0.001). Regression analysis showed a positive relationship between certification year and the proportion of traditional procedures performed by each provider (P<0.001). Multivariable regression models found that certification year, RUCA code, and estimated income of practice location were all significant predictors (P<0.02) of the proportion of traditional procedures performed by each provider. In the United States, physicians in metropolitan areas and more recent certification years are more likely to perform a larger proportion of traditional procedures. This finding suggests that the distribution of glaucoma procedure types is related to physician factors such as degree of urbanization and duration of practice. More research is needed to better understand how such differences affect patient access and outcomes.

Surgical Augmentation of the Suprachoroidal Space: A Novel Material and Implant.

Microinvasive glaucoma surgery (MIGS) has emerged as a safer method to lower IOP with minimal impact on patient quality of life compared to traditional glaucoma surgeries. With the advent of MIGS, there has been a renewed interest in exploring the suprachoroidal route. MIGS targeting the suprachoroidal space allow for a safe reduction in IOP while sparing conjunctiva and allowing "blebless" surgery, thus avoiding bleb-related complications. This article aims to review the rationale behind the suprachoroidal MIGS procedures and the literature surrounding the efficacy and safety of a novel suprachoroidal device, the MINIject. The available literature has shown promising IOP lowering results with the MINIject implant with a potentially safer and less invasive approach than traditional glaucoma surgeries.

Glaucoma Fellows-in-Training Recent Surgery Trends

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

Incidence and Clinical Characteristics of Postoperative Endophthalmitis After Ab-Interno Canaloplasty.

Postoperative endophthalmitis (POE) is a rare but devastating complication of ophthalmic surgeries. Microinvasive glaucoma surgery (MIGS) procedures have become increasingly utilized for the surgical reduction of intraocular pressure (IOP). Ab-interno canaloplasty (ABiC) is a popular MIGS procedure, but POE rates and clinical effects following ABiC have not been studied. This study conducted a retrospective review of all consecutive cases of either standalone ABiC or combined ABiC with phacoemulsification performed at a tertiary care academic referral center from 2015 to 2021. Exclusion criteria included a history of incisional glaucoma surgery, retinal surgery, or additional concurrent microinvasive glaucoma surgery (MIGS) at the time of ABiC. The ratesof POE afterABiC were calculated with 95% confidence intervals (CI) based on the Clopper-Pearson exact method. Of 3256 cases of ABiC, one case (0.03%, 1/3256, 95% CI: 0.00-0.17%) of post-ABiC endophthalmitis was identified. The rate of POE in standalone ABiC was 0.00% (0/1332 cases, 95% CI: 0.00-0.28%), whereas the rate in combined ABiC with phacoemulsification was 0.05% (1/1924 cases, 95% CI: 0.00-0.29%). Additionally, the rate of POE following stand-alone cataract surgery, 0.10%, 11/11,470 cases, 95% CI: 0.05-0.17%), total cataract surgeries, 0.06% (17/28,013 cases, 95% CI: 0.04-0.10%), total MIGs, excluding ABiC, surgeries, 0.08%, (3/3845 cases, 95% CI: 0.02-0.23%) portray non-inferiority of ABiC in the risk of POE. The case of ABiC-POE presented four days after surgery and required a vitreous tap with intraocular injection of antibiotics and pars plana vitrectomy. No causative organism was identified. A final 1-year follow-up revealed a corrected distance visual acuity of 20/40 and stable glaucoma. The rate ofPOE after ABiC (1 per 3256 cases) is statistically non-inferior to the reported incidence of POE after otherMIGS and incisional glaucoma surgeries.

Effectiveness of Microinvasive Glaucoma Surgery in the United States: Intelligent Research in Sight Registry Analysis 2013–2019

To evaluate the effectiveness of microinvasive glaucoma surgery (MIGS) with and without concurrent phacoemulsification. Multicenter, retrospective cohort study. Patients in the Intelligent Research in Sight (IRIS®) Registry who underwent Xen gel stent (ab interno) implantation, endoscopic cyclophotocoagulation (ECP), or goniotomy or canaloplasty from 2013 through2019. Kaplan-Meier survival analysis was used to assess reoperation rates. We defined reoperation as any subsequent glaucoma surgery occurring 1 month to 3 years after the initial procedure. Multivariable Cox proportional hazard models were used to determine factors predictive of reoperation. Reoperation rate, mean intraocular pressure (IOP) and visual acuity (VA), postoperative complications, predictors of reoperation, and reoperation procedure type. A total of 79 363 eyes from 57 561 patients were included, with 15 118 eyes (19%) receiving stand-alone MIGS and 64 245 eyes (81%) receiving MIGS concurrent with phacoemulsification. Overall, patients who underwent MIGS concurrently with phacoemulsification showed lower reoperation rates compared with stand-alone MIGS, most pronounced in ECP and goniotomy or canaloplasty. At postoperative year 2, the cumulative reoperation rate for stand-alone procedures was 15% for ECP, 24% for Xen implantation, and 24% for goniotomy or canaloplasty compared with 3% for ECP, 19% for Xen implantation, and 6% for goniotomy or canaloplasty concurrent with phacoemulsification (P < 0.001 for each stand-alone MIGS vs. MIGS with phacoemulsification). Black race, older age, moderate and severe glaucoma, higher baseline IOP, and glaucoma subtype were associated with higher reoperation risk. Although IOP decreased in all groups, stand-alone MIGS showed a more substantial decrease in mean IOP. Complication rates from MIGS were low overall: 1% for ECP, 1% for Xen implantation, and 2% for goniotomy or canaloplasty. In current United States clinical practice, MIGS has substantially lower reoperation rates when performed with phacoemulsification, especially for ECP and goniotomy or canaloplasty. Approximately one-sixth of patients undergoing stand-alone ECP and one-quarter of patients undergoing stand-alone Xen implantation or goniotomy or canaloplasty require reoperation by 2 years. Black race, diagnosis coding of moderate to severe glaucoma, and higher baseline IOP were associated with higher risk of reoperation after MIGS procedures. Proprietary or commercial disclosure may be found after the references.

Efficacy and Safety of iStent Inject Implantation in Manual and Femtosecond Laser-assisted Cataract Surgery before Lens Extraction.

AimTo describe the efficacy and safety of iStent implantation prior to phacoemulsification in manual as well as femtosecond laser-assisted cataract surgery (FLACS), and highlight this approach as a reasonable, if not necessary, step to advance one's ability and confidence in the use of microinvasive glaucoma surgery (MIGS) technology in phakic patients.MethodsA retrospective consecutive case series of patients with open angle glaucoma or ocular hypertension who underwent iStent inject implantation followed by cataract surgery (manual or FLACS). All cases underwent postoperative video review and were assessed and classified for intraoperative lens injury and hyphaema. Postoperative data included intraocular pressure (IOP), medication usage and adverse events.ResultsSixty-three eyes (n = 40 manual, n = 23 FLACS) were analyzed. Preoperatively, the mean IOP was 19.2 ± 4.9 mm Hg on 1.4 ± 0.96 mean medications, with 100% of eyes treated with medication. Intraoperatively, no lens injury was identified, and no significant hyphaema that impeded surgery occurred. At 6 months postoperative, mean IOP was 14.2 ± 1.8 mm Hg (38% reduction: p < 0.001), and >90% of eyes had IOP ≤ 16 mm Hg. The mean number of medications reduced to 0.11 ± 0.3 (92% reduction: p < 0.001), with 89% of eyes medication free. Safety was excellent for both manual and FLACS, with two iStents implanted in all eyes, and no cases of significant hyphaema or lens injury.ConclusionEarly implantation is safe, maximizes corneal clarity and angle visualization, avoids the risk of non-implantation due to surgical complications, and has a high success rate in both manual cataract surgery and the setting of FLACS.Clinical significanceThe conventional recommended approach of iStent implantation following cataract extraction has been adopted by many, however, with the advent of stand-alone procedures and concern about potential lens injury, there is an opportunity to gain experience with minimal risk in patients undergoing MIGS procedures combined with cataract surgery by implanting iStents at the start of the procedure. There is currently little emphasis or data published in the literature on an early approach to implantation to guide surgeons.How to cite this articleManning DK, Haider A, Clement C, et al. Efficacy and Safety of iStent Inject Implantation in Manual and Femtosecond Laser-assisted Cataract Surgery before Lens Extraction. J Curr Glaucoma Pract 2022;16(2):105-110.

Outcomes of Resident Performed Hydrus, iStent, and Kahook Glaucoma Procedures in a Predominantly African American Population.

This retrospective study characterized the efficacy and safety of 3 different microinvasive glaucoma surgery (MIGS) procedures in a predominantly African American population at the Philadelphia Veterans Affairs Hospital (Hydrus, Kahook, iStent), demonstrating no significant difference in intraocular pressure (IOP) and medication reduction between the 3 at long-term follow-up. To compare the efficacy and safety of 3 different MIGS procedures in a predominantly African American population. Retrospective cohort study of patients undergoing cataract extraction combined with 1 of 3 MIGS procedures (Hydrus, iStent, Kahook) at the Philadelphia Veterans Affairs Medical Center between January 1, 2015 and November 1, 2020. Analysis of variance and regression models were used to compare reduction in IOP and medication use among 3 MIGS types. A total of 123 eyes of 112 patients were included, including 56 (45.5%) eyes for Hydrus, 40 (32.5%) eyes for iStent, and 27 (22.0%) eyes for Kahook. Adjusted mean IOP reduction was greater for Hydrus at postoperative day 1 (-4.49 vs. -1.76 for iStent and -1.69 for Kahook, P=0.05 and greater for Kahook at postoperative week 1 (-2.53 vs. +0.70 for iStent vs. -1.41 for Hydrus, P=0.02), but did not differ significantly between MIGS types at subsequent postoperative visits (all P>0.05). In multivariable analysis, MIGS type was not significantly associated with reduction in IOP or medication use at 9 to 12 months postoperatively. There were no significant differences in complication rates across MIGS types. In this study, the difference in IOP lowering and medication reduction postoperatively between the Hydrus, iStent, and Kahook was not statistically significant after postoperative day 1. More studies are needed to evaluate outcomes of MIGS surgeries in glaucoma populations of different disease severity.

Microinvasive Glaucoma Surgery: An Evidence-Based Review

ABSTRACT Purpose: Interest in micro-invasive glaucoma surgery (MIGS) has exploded over the last 8 years with an increase in MIGS procedures of at least 400% in the United States, according to Medicare data. MIGS is an umbrella term that can cover many different types of surgeries. This review focuses on peer-reviewed evidence for Trabectome®, iStent inject ®, Kahook Dual Blade®, XEN® Gel Stent, and Hydrus®. Methods: We present key recent studies evaluating the efficacy and safety of MIGS in various types of glaucoma patients with different stages of disease. Conclusion: We conclude that MIGS is generally safe and efficacious, although only some MIGS have been studied through randomized clinical trials. When comparing and contrasting the different MIGS procedures, large prospective studies are not yet the norm. High-quality large prospective studies involving MIGS will be an important next step as ophthalmologists decide how to incorporate MIGS into their surgical armamentarium.

Survey of Microinvasive Glaucoma Surgery and Other Glaucoma Surgical Experience among United States Ophthalmology Residency Programs.

Purpose The aim of the study is to assess the state of glaucoma surgical training in United States ophthalmology residency programs, including experience with microinvasive glaucoma surgery (MIGS). Design The design of the study is anonymous, internet-based national survey. Participants Current United States ophthalmology residents of residency programs accredited by the Accreditation Council for Graduate Medical Education (ACGME). Methods An anonymous survey link was emailed to all 120 accredited United States ophthalmology residency programs inviting residents to participate in an assessment of residency glaucoma surgical experience. Survey responses were collected between January 21, 2019 and March 4, 2019 and analyzed using descriptive statistics. Main Outcome Measures The main outcomes of the study are demographic information, practice intentions, and anticipated primary surgical experience with ACGME-required glaucoma procedures and MIGS procedures, as self-reported by U.S. ophthalmology residents. Results Of the estimated 1,479 U.S. ophthalmology residents, 161 residents participated (10.9%). A total of 118 residents (73.2%) reported any degree of anticipated MIGS primary surgical experience during residency, with the iStent being the most familiar technique. The likelihood of any anticipated MIGS experience during residency was not significantly different by geographic region ( p = 0.16), however, anticipated volume varied significantly ( p = 0.037). Of the 113 respondents who reported an intention to manage glaucoma surgically in their eventual practice, 25 (22.1%) reported no anticipated primary MIGS experience during residency. 73.3% of residents anticipating MIGS experience anticipated 0 to 10 cases, with 42.9% anticipating less than 5 cases as primary surgeon. Conclusion MIGs are not a required component of the glaucoma surgical curriculum for U.S. ophthalmology residents. Although the majority of ophthalmology residents surveyed intend to manage glaucoma surgically in eventual practice, most receive minimal experience with these novel techniques during residency. Surgical training is variable by geographic region.

Safety and efficacy of microinvasive glaucoma surgery with cataract extraction in patients with normal-tension glaucoma

This study assesses the safety and efficacy of microinvasive glaucoma surgery (MIGS) with cataract extraction in patients with normal-tension glaucoma (NTG). In our sample of 45 NTG patients, mean intraocular pressure (IOP) decreased from 13.7 to 12.3 mmHg at 2.5 years, and mean medication burden decreased from 2.0 to 1.1 at 1.5 years. For success defined as IOP reduction ≥ 30% from baseline IOP with medication burden reduction from preoperative levels, success probability was 5.4% at 1.5 years. For success defined as medication burden reduction with an IOP reaching goal IOP as determined by the glaucoma specialist, success probabilities were 67.2% at 1.5 years and 29.4% at 2.5 years. At the last follow-up visit, eyes with two MIGS procedures with different mechanisms of action achieved successful medication reduction 68.8% of the time versus 35.7% achieved by a single MIGS procedure (p = 0.052). At their last visit, visual acuity was unchanged or improved in all eyes (100%). MIGS with cataract surgery results in modest reductions in IOP and medication burden in NTG patients, which may lead to lower costs and better therapeutic compliance. A combination of two MIGS procedures with different mechanisms of action may potentially be more effective in reducing medication burden than a single MIGS procedure in NTG patients. Further research is necessary to ascertain whether MIGS for NTG patients may help decrease medication burden while helping achieve goal IOP.

Changes in Performance of Glaucoma Surgeries 1994 through 2017 Based on Claims and Payment Data for United States Medicare Beneficiaries

To evaluate trends in glaucoma procedures in the United States Medicare population and to evaluate which physicians are performing newer procedures. Analysis of publicly available claims and payment data. Surgeons and beneficiaries enrolled in United States Medicare between 1994 and2017. Data regarding payments to physicians by the Centers for Medicare and Medicaid Services (CMS) were downloaded for the years 2012 through 2017. Data regarding claims to CMS by physicians were requested and processed between 1994 and 2017. Procedure counts from both data sets then were normalized for changes in the Medicare population, with 1995 as the baseline. The normalized volumes of procedures over time were visualized, as were geographic distributions of surgeons and their volume of procedures. Trends in procedure counts over time, geographic distribution of surgeons, and their volume of procedures. The number of trabeculectomies continues to decline and now is similar to the number of tubes. Use of the relatively new trabecular bypass shunts has increased rapidly. Surgeons performing these procedures are less likely to be performing traditional glaucoma surgeries as well. The number of laser-based cyclodestruction procedures increased after introduction of the endoscopic technique and again with the introduction of so-called micropulse procedures. The procedure counts obtained with physician payment data consistently are lower than those from claims data given the limitations of the payment data. Glaucoma practice patterns change each time a new device or procedure is introduced. Collectively, the use of new microinvasive glaucoma surgery procedures has increased rapidly such that they now account for a significant majority of glaucoma surgeries. Given the almost complete lack of comparative data to inform surgeon choices regarding these procedures, it will be important that randomized studies are carried out to fill this gap.

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To evaluate trends in glaucoma procedures in the United States Medicare population and to evaluate which physicians are performing newer procedures.Analysis of publicly available claims and payment data.Surgeons and beneficiaries enrolled in United States Medicare between 1994 and 2017.Data regarding payments to physicians by the Centers for Medicare and Medicaid Services (CMS) were downloaded for the years 2012 through 2017. Data regarding claims to CMS by physicians were requested and processed between 1994 and 2017. Procedure counts from both data sets then were normalized for changes in the Medicare population, with 1995 as the baseline. The normalized volumes of procedures over time were visualized, as were geographic distributions of surgeons and their volume of procedures.Trends in procedure counts over time, geographic distribution of surgeons, and their volume of procedures.The number of trabeculectomies continues to decline and now is similar to the number of tubes. Use of the relatively new trabecular bypass shunts has increased rapidly. Surgeons performing these procedures are less likely to be performing traditional glaucoma surgeries as well. The number of laser-based cyclodestruction procedures increased after introduction of the endoscopic technique and again with the introduction of so-called micropulse procedures. The procedure counts obtained with physician payment data consistently are lower than those from claims data given the limitations of the payment data.Glaucoma practice patterns change each time a new device or procedure is introduced. Collectively, the use of new microinvasive glaucoma surgery procedures has increased rapidly such that they now account for a significant majority of glaucoma surgeries. Given the almost complete lack of comparative data to inform surgeon choices regarding these procedures, it will be important that randomized studies are carried out to fill this gap.

Factors Associated With Unqualified Success After Trabecular Bypass Surgery: A Case-control Study.

An older age, a low number of baseline glaucoma medications, an early glaucoma stage, lower intraocular pressure (IOP) values during the first postoperative month, and combined surgery are possible predictors of unqualified success after a trabecular by-pass microinvasive glaucoma surgery (MIGS) procedure. The purpose of this study was to identify the potential predictors of unqualified success (IOP<18 mm Hg with no glaucoma medication) after trabecular by-pass MIGS. We designed a case-control study using logistic regression modeling that included all trabecular by-pass surgeries with at least 3 months of follow-up, performed at a single center from June 2017 to December 2019. Eyes that achieved an endpoint of unqualified success (dependent variable) were considered cases. All other eyes were used as the controls. Cases and controls were paired by sex and postoperative time. We tested the following independent variables: age, race, laterality (right eye or left eye), glaucoma stage, type of surgery (combined or stand-alone), type of trabecular bypass, intraoperative complications, baseline number of medications, baseline IOP, and postoperative IOP on days 1, 15, and 30. Additional analysis using IOP <15 mm Hg as a threshold and including eyes with at least 12 months of follow-up were performed. One hundred ninety-four eyes were included in the analysis. We observed complete success in 56.7% of eyes. The mean follow-up time for the entire population was 12.3±6.8 months. All variables were considered in the first step of the modeling process; however, only age, day-15 IOP, day-30 IOP, baseline number of medications, glaucoma stage, and type of surgery remained until the completion of our model, with adequate significance (P<0.05). The additional analysis confirmed our results. We identified that an older age, a low number of baseline glaucoma medications, an early glaucoma stage, lower IOP values during the first postoperative month, and combined surgery were associated with a higher chance of unqualified success at 12 months after a trabecular by-pass MIGS procedure.

Trends in Glaucoma Surgeries Performed by Glaucoma Subspecialists versus Nonsubspecialists on Medicare Beneficiaries from 2008 through 2016

To characterize the use of laser and incisional glaucoma surgeries among Medicare beneficiaries from 2008 through 2016 and to compare the use of these surgeries by glaucoma subspecialists versus nonsubspecialists. Retrospective, observational analysis. Medicare beneficiaries (n = 1 468 035) undergoing ≥1 laser or incisional glaucoma surgery procedure during 2008 through2016. Claims data from a 20% sample of enrollees in fee-for-service Medicare throughout the United States were analyzed to identify all laser and incisional glaucoma surgeries performed from 2008 through 2016. We assessed use of traditional incisional glaucoma surgery techniques (trabeculectomy and glaucoma drainage implant [GDI] procedure) and microinvasive glaucoma surgery (MIGS). Enrollee and procedure counts were multiplied by 5 to estimate use throughout all of Medicare. Linear regression was used to compare trends in use of glaucoma surgeries between ophthalmologists who could be characterized as glaucoma subspecialists versus nonsubspecialists. Numbers of laser and incisional glaucoma surgeries performed overall and stratified by glaucoma subspecialist status. The number of Medicare beneficiaries undergoing any glaucoma therapeutic procedure increased by 10.6%, from 218 375 in 2008 to 241 565 in 2016. The total number of traditional incisional glaucoma surgeries decreased by 11.7%, from 37 225 to 32 885 (P= 0.02). The total number of MIGS procedures increased by 426% from 13 705 in 2012 (the first year MIGS codes were available) to 58 345 in 2016 (P= 0.001). Throughout the study period, glaucoma subspecialists performed most of the trabeculectomies (76.7% in 2008, 83.1% in 2016) and GDI procedures (77.7% in 2008, 80.6% in 2016). Many MIGS procedures were performed by nonsubspecialists. The proportions of endocyclophotocoagulations, iStent (Glaukos; San Clemente, CA) insertions, goniotomies, and canaloplasties performed by glaucoma subspecialists in 2016 were 22.0%, 25.2%, 56.9%, and 62.8%, respectively. From 2008 through 2016, a large shift in practice from traditional incisional glaucoma surgeries to MIGS procedures was observed. Although glaucoma subspecialists continue to perform most traditional incisional glaucoma surgeries, many MIGS procedures are performed by nonsubspecialists. These results highlight the importance of training residents in performing MIGS procedures and managing these patients perioperatively. Future studies should explore the impact of this shift in care on outcomes and costs.

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 Cost and Economics of Endoscopic Cyclophotocoagulation in the United Kingdom: A Tertiary Center Experience.

As the only microinvasive glaucoma surgery (MIGS) with a reusable component, the cost per procedure of endoscopic cyclophotocoagulation (ECP) diminishes with each successive use. We present a cost comparison of ECP with other MIGS devices, based on our clinical practice. ECP delivers diode laser via a reusable probe to the ciliary processes under direct visualization. The aim of our study is to evaluate the direct cost of ECP based on a retrospective review of cases and compare the cost per procedure with other MIGS devices. We conducted a retrospective review of ECP procedures performed at St Thomas' Hospital over 4.5 years. The cost of the ECP endoscope and diode laser consoles, reusable probes, and maintenance contracts were obtained from the hospital procurement log. The on-site Central Sterile Services Department was contacted for probe sterilization and repackaging costs. The cost per device for ECP and commonly performed MIGS procedures were obtained from the product specialists of each company. A total of 332 procedures were performed using 37 ECP probes during the study period. Each reusable ECP laser probe was found to give an average of 8.97 laser treatments. The cost per procedure decreased over the course of 4.5 years from £819.43 for the first 42 cases to £341.50 after 332 cases. Compared with other MIGS devices, the cost per procedure of ECP after 100 procedures is second lowest to the Kahook Dual Blade and reduces with each successive procedure performed. The ability to reuse each ECP probe significantly lowers the cost per procedure compared with other MIGS devices in the United Kingdom. The cost per procedure continues to reduce with each successive procedure.

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

PurposeThe purpose of this study was to evaluate the safety and efficacy of microinvasive glaucoma surgery (MIGS) with 360° ab-interno trabeculotomy using the TRAB360 device as a stand-alone procedure in patients with refractory primary open-angle glaucoma (POAG) and preoperative IOP ≥18 mmHg.SettingThis study evaluated patients treated in a tertiary-referral clinical practice setting.DesignThis study is a retrospective analysis of 81 eyes.MethodsPatients with refractory open-angle glaucoma underwent stand-alone 360° ab-interno trabeculotomy using the TRAB360 device. Effectiveness was determined by reduction in medicated IOP and the use of medications from baseline. Safety was determined by the rate of adverse events and secondary surgical interventions. The time points assessed were baseline and postoperative day 1, week 1, and months 1, 3, 6, and 12. A subgroup analysis was performed on eyes with medicated preoperative IOP values of ≥25 mmHg.ResultsThe reductions in IOP from 1 day to 12 months postoperatively were statistically significant compared to baseline values. The mean reduction in IOP at 12 months was 7.3±6.7 mmHg from baseline. At 12 months, 59% eyes achieved ≥20% reduction in IOP and IOP <18 mmHg with the same or fewer numbers of IOP-lowering medications compared with those at baseline. The mean number of IOP-lowering medications was reduced from 1.7±1.3 at baseline to 1.1±1.0 at 12 months. At 12 months, 67% of eyes with preoperative IOP values of ≥25 mmHg achieved ≥20% reduction in IOP and IOP <18 mmHg with the same or fewer numbers of IOP-lowering medications compared with those at baseline. The most common adverse event for all eyes was mild, transient hyphema (57 eyes). During the first year after the procedure, 20 (25%) eyes were considered failures since they required reinterventions.ConclusionTrabeculotomy using the TRAB360 device resulted in significant IOP reductions up to 1 year with a favorable safety profile. The device is an effective stand-alone MIGS procedure for patients with refractory POAG.

Complications of micro-invasive glaucoma surgery.

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. 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. 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.

Interaction of primary human trabecular meshwork cells with metal alloy candidates for microinvasive glaucoma surgery.

Microinvasive glaucoma surgery (MIGS) is a relatively new addition to the glaucoma treatment paradigm. Small metallic stents are inserted into the trabecular meshwork in order to increase aqueous humour drainage. MIGS procedures are rapidly being adopted owing to a more favourable side effect profile when compared with traditional surgery. Remarkably, this rapid rate of utilization has occurred without any published studies on the effect of metal alloys used in these stents on human trabecular meshwork cells (HTMCs). Therefore, this study aimed to determine the effect of candidate metal alloys for MIGS on HTMC morphology, viability and function. Human trabecular meshwork cells were cultured on the surfaces of titanium (polished and sandblasted), a titanium-nickel (nitinol) alloy and glass (as control substratum). Fluorescence imaging was used to assess cell morphology and spreading. A lactate dehydrogenase cytotoxicity assay, cell death detection ELISA, MTT cell viability assay, BrdU cell proliferation assay and fibronectin ELISA were also conducted. Cells cultured on sandblasted titanium exhibited significantly greater spreading than cells cultured on other substrata. In comparison, HTMCs cultured on nitinol displayed poor spreading. Significantly more cell death, by both necrosis and apoptosis, occurred on nitinol than on titanium and glass. Also, cell viability and proliferation were suppressed on nitinol compared with titanium or glass. Finally, HTMCs on both titanium and nitinol produced greater amounts of fibronectin than cells grown on glass. Substratum topography and metal alloy composition were found to impact morphology, viability and function of primary HTMC cultures.

A Comparison of Endothelial Cell Loss in Combined Cataract and MIGS (Hydrus) Procedure to Phacoemulsification Alone: 6-Month Results.

Purpose. To compare the corneal endothelial cell loss after phacoemulsification, alone or combined with microinvasive glaucoma surgery (MIGS), in nonglaucomatous versus primary open angle glaucoma (POAG) eyes affected by age-related cataract. Methods. 62 eyes of 62 patients were divided into group 1 (n = 25, affected by age-related cataract) and group 2 (n = 37, affected by age-related cataract and POAG). All patients underwent cataract surgery. Group 2 was divided into subgroups A (n = 19, cataract surgery alone) and B (n = 18, cataract surgery and MIGS). Prior to and 6 months after surgery the patients' endothelium was studied. Main outcomes were CD (cell density), SD (standard deviation), CV (coefficient of variation), and 6A (hexagonality coefficient) variations after surgeries. Results. There were no significant differences among the groups concerning preoperative endothelial parameters. The differences in CD before and after surgery were significant in all groups: 9.1% in group 1, 17.24% in group 2A, and 11.71% in group 2B. All endothelial parameters did not significantly change after surgery. Conclusions. Phacoemulsification determined a loss of endothelial cells in all groups. After surgery the change in endothelial parameters after MIGS was comparable to the ones of patients who underwent cataract surgery alone.