Traditional Glaucoma Surgery Research Articles

Trends in glaucoma surgery in a tertiary hospital in Spain: 2010-2022.

This study aims to conduct an analysis glaucoma surgeries performed over a 13-year period at a tertiary hospital affiliated with the Spanish National Health System, with the goal of assessing temporal trends. This retrospective observational study scrutinized surgeries undertaken in the glaucoma unit of a tertiary center in Spain between 2010 and 2022. Data collected included surgical dates, procedure performed, whether it was standalone or combined, as well as patient demographics including age, sex, and type of underlying glaucoma. Surgeries on individuals under 18 years of age were excluded. An annual comparative analysis was performed to ascertain the evolving trends in glaucoma surgical interventions. A total of 12,944 surgeries were included in the analysis, comprising 9428 isolated cataract surgeries and 2975 glaucoma procedures. Trabeculectomy, glaucoma drainage devices (GDD), and cyclodestruction, collectively referred to as traditional surgery, demonstrated a decline from 93.2% to 23.6% over the study duration. Minimally invasive glaucoma surgery (MIGS) and minimally invasive bleb surgery (MIBS) demonstrated a significant increase from 3.8% in 2010 to 74.7% in 2022, relative to the total glaucoma surgeries. Furthermore, combined surgeries manifested a noteworthy increase from 39.0% in 2010 to 44.2% in 2022, with 86.4% of combined procedures in 2022 being MIGS or MIBS. In recent years, there has been a noticeable change in the trend of glaucoma surgeries, with MIGS and MIBS procedures experiencing a significant increase and becoming the most commonly performed glaucoma procedures. Consequently, traditional glaucoma surgeries have decreased in frequency.

Minimally invasive, maximally impactful: minimally invasive glaucoma surgery and the changing glaucoma landscape.

The advent of minimally invasive glaucoma surgery (MIGS) procedures has ushered in a new era of interventional glaucoma. MIGS has expanded the treatment options for surgeons necessitating a rethinking of the optimal management strategy for patients with glaucoma. There are several new MIGS devices and procedures available to glaucoma surgeons. With several options available, patient selection is crucial to maximize the utility of MIGS in the context of traditional glaucoma surgery. A management algorithm is presented based on our practice pattern to help guide decision-making for glaucoma surgeons. Although we encourage surgeons to continue to broaden their toolkit, we emphasize the continued importance of teaching the next-generation traditional glaucoma surgery in the MIGS era. Future prospective studies are warranted to elucidate the optimal treatment strategy for patients with glaucoma.

A Comprehensive Review of Recent Advances in Minimally Invasive Glaucoma Surgery: Current Trends and Future Directions.

Glaucoma, a leading cause of blindness globally, necessitates effective management strategies to prevent irreversible vision loss. Traditional glaucoma surgeries, while effective, are associated with significant risks and complications. Minimally invasive glaucoma surgery (MIGS) has emerged as a transformative approach, offering safer and less invasive alternatives. This review provides a comprehensive overview of recent advancements in MIGS, highlighting current trends, technological innovations, and future directions. MIGS procedures, characterized by smaller incisions and quicker recovery times, have expanded the therapeutic landscape, enabling earlier intervention and improved patient outcomes. The review evaluates various MIGS techniques, their efficacy, safety profiles, and clinical outcomes, drawing insights from comparative studies and meta-analyses. Technological innovations, including enhanced device designs and integration with digital health technologies, have further bolstered the field. Despite challenges in patient selection and long-term outcomes, the future of MIGS is promising, with ongoing research and development poised to enhance its impact. By synthesizing the latest research, this review aims to inform clinicians, researchers, and policymakers, ultimately contributing to improved management of glaucoma and patient care.

Is the Advent of New Surgical Procedures Changing the Baseline Features of Patients Undergoing First-Time Glaucoma Surgery?

Background: The aim of this study was to determine if the rise in new surgical procedures for glaucoma is changing the baseline features of patients. Methods: In this retrospective study, we reviewed the baseline features of patients undergoing their first glaucoma surgery in 2011 and 2021, collecting data regarding intraocular pressure (IOP), visual field (VF) parameters, stage of disease, and the type of surgery. Results: In the study, 455 patients were included in the analysis. From these, 230 eyes had glaucoma surgery performed in 2011 (Group A) and 225 eyes in 2021 (Group B). When considering the baseline features, Group A was older than Group B (72.7 ± 10.7 and 70 ± 12.4 years; p = 0.02, respectively), and showed a significantly more advanced VF mean defect (-16.4 ± 8.8 and -13.8 ± 8.7 dB; p < 0.01, respectively) and a higher IOP (25.9 ± 6.6 and 24.9 ± 7.8 mmHg; p = 0.02, respectively). Overall, severe VF damage at the time of surgery was more frequent in Group A (74.3%) than in Group B (60.8%) (p < 0.01). The overall number of traditional glaucoma surgeries was 211 in 2011, reducing to 94 ten years later, with similar severe pre-operative VF defects. In 2021, minimally invasive bleb surgery (MIBS) represented 58% of all surgeries. Conclusions: In the last ten years, patients receiving glaucoma surgery for the first time were younger, had less severe disease, and a more contained IOP. The baseline feature modifications were probably related to the diffusion of new procedures, especially MIBS, which allowed for treating patients at an earlier stage, reserving traditional procedures for advanced cases.

Glaucoma surgery experiments using digital microscope-integrated optical coherence tomography and OCT-compatible instruments

There is a certain failure rate in traditional glaucoma surgery because of the lack of depth information in microscope images. In this work, we present a digital microscope-integrated optical coherence tomography (MIOCT) system and several custom-made OCT-compatible instruments for glaucoma surgery. Sixteen ophthalmologists were asked to perform trabeculectomy and canaloplasty on live porcine eyes using the system and instruments. After surgery, a subjective feedback survey about the user experience was taken. The experiment results showed that our system can help surgeons easily locate important tissue structures during surgery. The custom-made instruments also solved the shadowing problem in OCT imaging. Surgeons preferred to use the system in their future practice.

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

ObjectiveAngle-based minimally invasive glaucoma surgery (ab-MIGS) has grown substantially, although long-term efficacy is poorly understood. We analyze ab-MIGS effectiveness with/without preceding laser trabeculoplasty (LTP). DesignRetrospective cohort study SubjectsEyes undergoing ab-MIGS (Canaloplasty, Goniotomy, Trabectome, iStent) with/without prior SLT (<2 years preceding MIGS) were identified in the IRIS® Registry (Intelligent Research in Sight) 2013-2018. MethodsPropensity score matching (PSM) was undertaken to define 4 cohorts: (i) standalone ab-MIGS, no prior LTP vs (ii) standalone ab-MIGS, with prior LTP; and (iii) ab-MIGS + phacoemulsification, no prior LTP vs (iv) ab-MIGS + phacoemulsification, with prior LTP. Main Outcome MeasuresFailure was defined as subsequent glaucoma reoperation following ab-MIGS (either MIGS or traditional glaucoma surgery). Time to event outcome and incidence rates were calculated using survival analysis, and adjusted hazard ratios (aHR) generated using multivariate Cox proportional hazards models. Medication data was not available for analysis. Results164,965 unique MIGS procedures were performed, from 2013-2018. After PSM, we identified 954 eyes undergoing standalone ab-MIGS and 7,522 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=3,761) were more likely to undergo reoperation vs those without LTP (n=3,761) 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). ConclusionsPrior 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 in understanding who may benefit most from ab-MIGS, and guiding patient and surgeon treatment expectations.

The Evolution and Current Landscape of Minimally Invasive Glaucoma Surgeries: A Review.

This review examines the evolution, current status, and future potential of minimally invasive glaucoma surgeries (MIGS), a significant advancement in the treatment of glaucoma, a leading cause of irreversible blindness. MIGS offer a less invasive alternative to traditional glaucoma surgeries, primarily aimed at reducing intraocular pressure, minimizing tissue trauma, and providing a safer profile. With the emergence of devices such as the Trabectome, iStent, and others, MIGS have expanded the surgical toolkit, allowing personalized, patient-centered care. Despite their advantages, MIGS face challenges such as efficacy in severe cases, long-term data, and accessibility. Ongoing research and technological innovations continue to refine their capabilities and applications, promising to further transform glaucoma management and patient outcomes. This paper provides an in-depth analysis of MIGS, reflecting on their impact and contemplating future directions in this dynamically evolving field.

European Glaucoma Society – A guide on surgical innovation for glaucoma

PROLOGUE: Glaucoma surgery has been, for many decades now, dominated by the universal gold standard which is trabeculectomy augmented with antimetabolites. Tubes also came into the scene to complement what...

Addressing Glaucoma in Myopic Eyes: Diagnostic and Surgical Challenges.

Epidemiological and genetic studies provide strong evidence supporting an association between myopia and glaucoma. The accurate detection of glaucoma in myopic eyes, especially those with high myopia, remains clinically challenging due to characteristic morphologic features of the myopic optic nerve in addition to limitations of current optic nerve imaging modalities. Distinguishing glaucoma from myopia is further complicated by overlapping perimetric findings. Therefore, longitudinal follow-up is essential to differentiate progressive structural and functional abnormalities indicative of glaucoma from defects that may result from myopia alone. Highly myopic eyes are at increased risk of complications from traditional incisional glaucoma surgery and may benefit from newer microinvasive glaucoma surgeries in select cases.

Minimally Invasive Glaucoma Surgery: A Review of the Literature.

Minimally invasive glaucoma surgery (MIGS) has emerged as a novel approach in the glaucoma treatment spectrum, offering a range of diverse procedures and devices aimed at reducing intraocular pressure (IOP). MIGS can be broadly classified into several categories: those that enhance trabecular outflow (Trabectome, iStent, Hydrus Microstent, Kahook Dual Blade, high frequency deep sclerotomy, and gonioscopy-assisted transluminal trabeculotomy), those that augment suprachoroidal outflow (CyPass Microstent and iStent Supra), those that target Schlemm's canal (TRAB360 and the OMNI Surgical System, Streamline, and Ab Interno Canaloplasty), and conjunctival bleb-forming procedures (EX-PRESS Glaucoma Filtration Device, Xen Gel Stent and PreserFlo MicroShunt). MIGS is considered to have a shorter surgical time and fewer severe complications when compared to traditional glaucoma surgeries such as trabeculectomy and glaucoma drainage device implantation (Ahmed, Baerveldt, and Molteno valves). This literature review comprehensively examines the distinct MIGS devices and procedures, their underlying mechanisms, and clinical outcomes, emphasizing the importance of evaluating the efficacy and complications of each approach individually. As the field of MIGS continues to evolve, it is crucial to prioritize high-quality, long-term studies to better understand the safety and effectiveness of these innovative interventions in glaucoma management.

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.

Safety and Efficacy of Resident-Performed Gonioscopy-Assisted Transluminal Trabeculotomy.

GATT can be performed efficaciously and safely by PGY-3 and PGY-4 residents, with clinical outcomes and complication rates that mirror those of attending-performed GATT cohorts from the literature. Report outcomes of gonioscopy-assisted transluminal trabeculotomy (GATT) performed by PGY-3 and PGY-4 residents. A retrospective chart review was performed for patients undergoing resident-performed GATT. Eyes with previous traditional glaucoma surgery (trabeculectomy or aqueous shunt) or neovascular glaucoma were excluded from this analysis. The primary aim was to assess whether resident-performed GATTs demonstrated success rates comparable with the GATT literature. Surgical success was defined as intraocular pressure (IOP)<21mmHg, and an IOP reduction of 20% from baseline, and no subsequent IOP-lowering surgery. The secondary and tertiary aims were to describe complication rates and operating times for resident-performed GATTs, respectively. A total of 50 eyes from 40 patients with various types of glaucoma were included. Eyes either underwent resident-performed GATT-alone (N=9) or GATT+cataract extraction with intraocular lens implantation (CEIOL) (N=41). The surgical success rate at 6 months was 71% for GATT-alone and 42% for GATT+CEIOL. Three eyes required subsequent IOP-lowering surgery. The hyphema rate was 16% at postoperative week 1 and 6% at postoperative month 1. The IOP spike (>30mmHg) rate was 18%. Mean surgical time for both GATT-alone and GATT+CEIOL was longer for PGY-4s than for PGY-3s, attributable to less attending assistance during PGY-4 cases and more resident-performed cataracts in PGY-4 GATT+CEIOL cases (85%) compared with PGY-3 cases (35%). GATT can be performed efficaciously and safely by PGY-3 and PGY-4 residents, with clinical outcomes and complication rates that mirror those of attending-performed GATT cohorts from the literature.

Trabeculectomy indications – when to do it (Trab vs MIGS)

AbstractTrabeculectomy still remains the gold standard in glaucoma surgery, being the only operation that can potentially lead to single digit IOP control. Indications for trabeculectomy have not changed throughout the years in glaucoma management and even with the new EGS guidelines, trabeculectomy still represents what is called “traditional glaucoma surgery”. With the evolution of MIGS (Minimally Invasive Glaucoma Surgery) there has been a broad debate between the use of trabecvulectomy and the gradual replacement by MIGS. In this presentation the indication of trabeculectomy and MIGS will be explained, with specific emphasis on how MIGS complement trabeculectomy and fill the gap between drops and traditional incisional glaucoma surgery. Clinical paradigms will also be presented.

Evaluation of a Novel Αb Εxterno MicroShunt for the Treatment of Glaucoma.

The surgical management of glaucoma has been revolutionized by the introduction of minimally invasive glaucoma surgery (MIGS). The various MIGS options aim to meaningfully lower intraocular pressure with a better safety profile than traditional glaucoma surgery. The key clinical attributes and the emerging potential of an ab externo MicroShunt (PreserFlo™) are reviewed in the context of published evidence and clinical experience. This novel MicroShunt consists of an 8.5-mm-long tube that is implanted in the eye via an ab externo approach enabling aqueous humor drainage into the sub-Tenon’s space through the formation of a bleb, similar in appearance to that created by trabeculectomy. The efficacy and safety of this procedure, the concomitant use of antimetabolites, the impact of tube positioning, and its future value in clinical practice are critically reviewed. Recent evidence has demonstrated the MicroShunt to be less effective than traditional filtration surgery, but with a significant improvement in safety. Cumulative data suggest that the new implant provides tangible clinical benefits to selected patients with glaucoma in need of further intraocular pressure (IOP) lowering. Future research should delineate the precise role of this and other MIGS options in the rapidly evolving glaucoma treatment algorithm.

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

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. 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. 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. 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, withouteliciting a severe biological response.

Twenty-Four-Month Outcome of Gonioscopy-Assisted Transluminal Trabeculotomy (GATT) in Eyes With Prior Corneal Transplant Surgery.

Glaucoma is a well-known sequelae of corneal transplant surgery and is a leading cause of visual loss in this patient group. We evaluated the performance and safety of gonioscopy-assisted transluminal trabeculotomy (GATT) in this population. Noncomparative retrospective case series. Consecutive eyes of patients receiving the GATT procedure for uncontrolled intraocular pressure (IOP) following corneal transplant surgery from 2016 to 2019. Retrospective analysis of eyes with a history of prior corneal transplant undergoing GATT at Glaucoma Associates of Texas between 2016 and 2019 was performed. Data included IOP, patient demographics, preoperative and postoperative medications, preoperative and postoperative corneal procedures, complications, and need for reoperation for IOP control. IOP reduction and medication use following the procedure. Thirty-nine eyes of 32 patients with prior corneal transplant surgery underwent a GATT procedure. Prior corneal surgery included penetrating keratoplasty (59.0%), Descemet's stripping endothelial keratoplasty (35.9%), Descemet's membrane endothelial keratoplasty (2.6%), and deep anterior lamellar keratoplasty (2.6%). Patient age ranged from 24 to 94 years (mean 68.0 y) with 44% female and 81% Caucasian. The majority of patients had secondary open angle glaucoma (64.1%). There was a significant reduction in IOP and number of medications at all postoperative time points after censoring patients requiring reoperation to control IOP (P<0.001). At 24 months the pressure decreased from baseline of 30.9±11.5 to 13.9±4.7 mm Hg. Medications decreased from 4.2±1.0 medications at baseline to 0.6±1.0 at 24 months. Visual acuities decreased significantly over the first postsurgical month (all P<0.05), but these recovered at subsequent follow-up visits with 2-Snellen line improvements exceeding losses from month 3 to 36. Seven eyes required reoperation for uncontrolled glaucoma at a median of 8.5 months (range: 1.6 to 16.2 mo) after GATT. The cumulative proportion of eyes undergoing repeat cornea surgery was 2.6%, 2.6%, and 14.3% at 12, 24, and 36 months post-GATT, respectively. This case series describes a group of glaucoma patients, with a history of prior corneal surgery, that were safely and successfully treated with GATT. While classically traditional glaucoma surgeries are considered the standard of care for eyes following corneal transplant surgery, GATT should be considered as a reasonable, safe and effective alternative for surgically lowering IOP.

Effects of Postoperative Intravitreal Injections on Outcomes of Traditional Glaucoma Surgery in Patients with Preoperative Intravitreal Injections

To compare outcomes of glaucoma drainage device (GDD) implantation and trabeculectomies with and without postoperative intravitreal injections (IVIs) in glaucoma patients with a history of preoperative IVIs. Retrospective cohort study. A total of 133 eyes of 133 glaucoma patients who underwent GDD implantation or trabeculectomy with at least 1 IVI preoperatively between January 2005 and October 2020 at Massachusetts Eye and Ear. Chart review of glaucoma patients with traditional glaucoma surgery and at least 1 IVI before surgery. All statistical analyses were conducted with R statistical programming software. Intraocular pressure (IOP), medication burden, best-corrected visual acuity (BCVA), Kaplan-Meier success rates, adjusted hazard ratios (HRs), and complications. Baseline demographics were similar between the groups with and without postoperative IVIs. The group with postoperative IVIs had a higher proportion of diabetic retinopathy and retinal vascular occlusions than the group without postoperative IVIs, which had more eyes with age-related macular degeneration. Intraocular pressure, medication burden, and visual acuity were similar between groups at all time points except for IOP at 6 weeks, which was lower in the group with postoperative IVIs. The group with postoperative IVIs had significantly more preoperative IVIs than the group without postoperative IVIs (6.6 vs. 3.3, P= 0.017). For success defined as IOP reduction ≥ 20% with 5 < IOP ≤ 21 mmHg, Kaplan-Meier analyses demonstrated similar success rates between groups with and without IVIs. When stratified by the number of IVIs, success rates for the group with 7 or more IVIs were significantly higher than the success rates for the group with 0-6 IVIs (P= 0.005). Each additional postoperative IVI resulted in a 7.2% decrease in the hazard of failure to achieve our stated success criteria. With regard to late complications, the group with postoperative IVIs had a higher incidence of vitreous hemorrhage (18.5% vs. 3.2%, P= 0.039) than the group without postoperative IVIs. A higher number of postoperative IVIs, specifically 7 or more IVIs, may be associated with improved success rates of traditional glaucoma surgery in glaucoma patients who received IVIs before surgery.

Minimally Invasive Glaucoma Surgical Techniques for Open-Angle Glaucoma

Glaucoma affects more than 75 million people worldwide. Intraocular pressure (IOP)-lowering surgery is an important treatment for this disease. Interest in reducing surgical morbidity has led to the introduction of minimally invasive glaucoma surgeries (MIGS). Understanding the comparative effectiveness and safety of MIGS is necessary for clinicians and patients. To summarize data from randomized clinical trials of MIGS for open-angle glaucoma, which were evaluated in a suite of Cochrane reviews. The Cochrane Database of Systematic Reviews including studies published before June 1, 2021. Reviews of randomized clinical trials comparing MIGS with cataract extraction alone, other MIGS, traditional glaucoma surgery, laser trabeculoplasty, or medical therapy. Data were extracted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines by one investigator and confirmed by a second. Methodologic rigor was assessed using the AMSTAR 2 appraisal tool and random-effects network meta-analyses were conducted. The proportion of participants who did not need to use medication to reduce intraocular pressure (IOP) postsurgery (drop-free). Outcomes were analyzed at short-term (<6 months), medium-term (6-18 months), and long-term (>18 months) follow-up. Six eligible Cochrane reviews were identified discussing trabecular bypass with iStent or Hydrus microstents, ab interno trabeculotomy with Trabectome, subconjunctival and supraciliary drainage devices, and endoscopic cyclophotocoagulation. Moderate certainty evidence indicated that adding a Hydrus safely improved the likelihood of drop-free glaucoma control at medium-term (relative risk [RR], 1.6; 95% CI, 1.4 to 1.8) and long-term (RR, 1.6; 95% CI, 1.4 to 1.9) follow-up and conferred 2.0-mm Hg (95% CI, -2.7 to -1.3 mm Hg) greater IOP reduction at long-term follow-up, compared with cataract surgery alone. Adding an iStent also safely improved drop-free disease control compared with cataract surgery alone (RR, 1.4; 95% CI, 1.2 to 1.6), but the short-term IOP-lowering effect of the iStent was not sustained. Addition of a CyPass microstent improved drop-free glaucoma control compared with cataract surgery alone (RR, 1.3; 95% CI, 1.1 to 1.5) but was associated with an increased risk of vraision loss. Network meta-analyses supported the direction and magnitude of these results. Based on data synthesized in Cochrane reviews, some MIGS may afford patients with glaucoma greater drop-free disease control than cataract surgery alone. Among the products currently available, randomized clinical trial data associate the Hydrus with greater drop-free glaucoma control and IOP lowering than the iStent; however, these effect sizes were small.

Updates on the utility of anterior segment optical coherence tomography in the assessment of filtration blebs after glaucoma surgery.

The formation of filtration blebs is the main drainage mechanism for reducing intraocular pressure after traditional incisional glaucoma surgery such as trabeculectomy and non-penetrating deep sclerotomy. Early and short-lasting blebs may also occur after canaloplasty. Bleb formation also plays an important role after the implantation of glaucoma drainage devices, including Minimally Invasive Glaucoma Surgery devices. Anterior segment optical coherence tomography (AS-OCT) is a rapid and non-invasive high-resolution imaging technique that has evolved in recent years to become a routine examination. Anterior segment optical coherence tomography (AS-OCT) provides key information in the assessment and follow-up of glaucoma surgery, especially in the assessment of filtration blebs. Thus, bleb morphology can be qualitatively classified into diffuse, cystic, encapsulated and flattened, and AS-OCT imaging can also provide several quantitative parameters of the bleb, such as total bleb height, bleb fluid-filled cavity height, bleb wall thickness, number of microcysts and trabeculectomy opening size. These parameters could have an impact on clinical management during follow-up because they may predict the success or failure of the surgery in the early and late postoperative periods. Additionally, they may also guide the procedures used to increase filtration and reduce intraocular pressure, such as bleb needling and laser suture lysis.

Microinvasive Glaucoma Surgery in US Ophthalmology Residency: Surgical Case Log Cross-sectional Analysis and Proposal for New Glaucoma Procedure Classification.

A cross-sectional sample of the US ophthalmology residency graduating class of 2018 revealed that 18.4% of residents logged <5 traditional glaucoma surgeries, and 63.4% logged at least 1 microinvasive glaucoma surgery (MIGS). Describe the state of MIGS in US ophthalmology residency training and propose a glaucoma procedure classification system for residents' surgical case logs. Deidentified case logs from residents graduating in 2018 were requested from US residency program directors. Case logs were received for 152/488 (31%) residents from 36/115 (31%) programs. The mean number of traditional glaucoma surgeries per resident was 9.0±5.9 (range: 0 to 31). The mean number of MIGS per resident was 5.2±8.9 cases (range: 0 to 58). There were 28/152 (18.4%) residents from 16/36 (44.4%) programs who logged <5 traditional glaucoma surgeries as primary surgeon, and 3/152 (2.0%) residents from 3/36 (8.3%) programs who logged zero traditional glaucoma surgeries as primary surgeon. There were 98/152 (64.5%) residents from 32/36 (88.8%) programs who logged <5 MIGS as primary surgeon, and 48/152 (31.6%) residents from 25 of 36 (69.4%) programs who logged zero MIGS as primary surgeon. There were 104/152 (63.4%) residents from 33/36 (91.6%) programs who logged at least 1 MIGS as primary surgeon; there were 3/36 (8.3%) residency programs where no resident logged any MIGS as primary surgeon. US ophthalmology residents' MIGS experience varies widely. Residents can satisfy glaucoma surgery requirements with some MIGS, even in the absence of adequate traditional glaucoma surgeries. We propose a residency case log classification system that better reflects the growing role of MIGS in clinical practice and helps ophthalmic educators more accurately track procedures requiring related skills.