Minimally Invasive Glaucoma Surgery Research Articles

To discuss the minimally invasive glaucoma surgery related to trabeculotomy from the perspective of physiological function of trabecular meshwork drainage pathway

The advent of minimally invasive glaucoma surgery (MIGS) has broadened the therapeutic options for managing glaucoma. In recent years, MIGS procedures targeting the trabecular meshwork-Schlemm's canal aqueous outflow resistance site have garnered significant attention. This focus has extended to the pathophysiological changes occurring within the aqueous outflow pathway. However, questions persist regarding the efficacy of near-peripheral or peripheral trabeculotomy in achieving the anticipated reduction of outflow resistance and the suitability of MIGS surgery for patients with primary open-angle glaucoma. By integrating clinical experience with pertinent clinical research, this paper advocates for a reevaluation of MIGS procedures to aid clinicians in making informed decisions regarding various glaucoma surgical interventions.

False Passage of 5-0 Polypropylene Suture into Episcleral Vein during Gonioscopy Assisted Transluminal Trabeculotomy

Gonioscopy-assisted transluminal trabeculotomy (GATT) is a promising cost effective minimally invasive glaucoma surgery (MIGS). The main advantage being safety with regards to low risk for hypotony and its related complications. However, the Schlemm’s canal (SC) based procedures have a different set of complications, the most common being hyphema and transient intraocular pressure spike. The other rare complications being, false passage of the suture by traversing the external wall of the SC into the suprachoroidal space or posterior chamber; or breaching the internal wall of SC into the anterior chamber. Although these complications are rare, knowledge about them is important not only for early identification but for prevention and management if they occur. Through this case report, we describe a rare complication where the suture had traversed through a dilated episcleral vein during GATT. To our knowledge, there has been no prior report of such a complication.

Clinical applications of aqueous angiography in glaucoma.

Aqueous humor outflow (AHO) pathways are the main site of resistance causing elevated intraocular pressure in glaucoma, especially primary open-angle glaucoma patients. With the recently introduced technique of aqueous angiography (AA); functional, real time assessment of AHO from proximal (trabecuar meshwork) to distal pathways under physiological conditions has been made possible. AHO pathways are segmental, and AA can identify high-flow region (increased angiographic signals) and low flow region (decreased angiographic signals) in an individual. With the introduction of canal-based minimally invasive glaucoma surgeries (MIGS), the assessment of AHO can help guide the placement of stents/incisions during MIGS procedures. This can allow individualized and targeted MIGS procedures in glaucoma patients for better results. Based on the density of AHO pathways visualized on AA, surgeons can decide whether to perform MIGS or conventional glaucoma surgery for improved outcomes for the patient. Immediate intraoperative assessment for functionality of the MIGS procedure performed is possible with AA, allowing for surgical adjustments of MIGS procedure in the same sitting, if needed. This review provides a summary of the studies performed with AA to date, with a special focus on Indian patients. It covers the basics and clinical applications of AA for improving surgical outcomes in glaucoma patients.

Corneal endothelial safety profile in minimally invasive glaucoma surgery.

To compare 5-year corneal endothelial safety of 3 minimally invasive glaucoma surgery (MIGS) devices (iStent inject , Hydrus Microstent, CyPass Micro-Stent). U.S. multicenter trials. Post hoc 5-year analysis from prospective randomized single-masked pivotal trials. Mild to moderate open-angle glaucoma subjects received a MIGS implant with phacoemulsification (implant + phaco) or phaco alone (control). In addition, 5-year end points comparing the implant and control groups included proportion of eyes with significant endothelial cell loss (ECL) (>30% or ≥30% vs baseline) and mean endothelial cell density (ECD). Comparable proportions of eyes in the iStent inject + phaco and control groups had significant 60-month ECL (9.4% vs 6.3%, respectively, diff: 3.2%, 95% CI, -5.0% to 11.3%, P = .77). Hydrus (20.8% vs 10.6%, diff: 10.2%, 95% CI, 3.2% to 17.2%, P = .01) and CyPass (27.2% vs 10.0%, diff: 17.2%, 95% CI, 5.6% to 28.7%, P = .02) had more eyes with ECL vs controls (iStent inject 1.49X, Hydrus 1.96X, CyPass 2.72X vs controls). Mean ECD over 60 months for iStent inject was indistinguishable vs control, whereas greater ECL was observed primarily 3 months postoperative (Hydrus) or accelerated after 2 years (CyPass). No iStent inject or Hydrus subjects developed persistent corneal edema, whereas 7 CyPass-implanted eyes developed ECL-related complications. Through 5 years postoperative, there were no differences in proportion of eyes with significant ECL or mean ECD between the iStent inject and control groups. There was greater 5-year ECL and lower ECD in the Hydrus and CyPass groups vs controls. The Hydrus ECL rate mirrored control after 3 months; the CyPass ECL rate accelerated vs control.

Ab Interno Minimally Invasive Glaucoma Surgery Combined with Cataract Surgery and Cataract Surgery Alone: IRIS® Registry Study

PurposeDescribe real-world characteristics and outcomes in patients undergoing Food and Drug Administration (FDA) approved/cleared ab interno Minimally Invasive Glaucoma Surgery (MIGS) combined with cataract surgery or cataract surgery alone. DesignAn observational, retrospective study of glaucomatous disease treated with MIGS (OMNI® Surgical System, Hydrus®, iStent Inject®) combined with cataract surgery or cataract surgery alone, documented in the American Academy of Ophthalmology IRIS® Registry (Intelligent Research in Sight) MethodsThe study period was between 07/01/2017 and 12/31/2022. Eligible patients were identified via Current Procedural Terminology (CPT) codes coupled with electronic health records. Outcomes included intraocular pressure (IOP) and IOP-lowering medication class usage over 24 months stratified by baseline IOP (≤18 and >18 mmHg). Bonferroni testing (p<0.0125) were applied. ResultsGlaucomatous disease was identified for 77,391 (OMNI: 428, Hydrus: 1,435, iStent Inject: 4,769, cataract surgery alone: 70,759) patients (109,745 eyes). For patients with a baseline IOP >18 mmHg, significant (p<0.001) change in IOP (OMNI -6.64 [SD 7.59], Hydrus -5.71 [6.30], iStent Inject -4.96 [7.30], cataract surgery alone -5.55 [6.41]) and medication usage (OMNI -1.34 [1.48], Hydrus -1.20 [1.18], iStent Inject -0.86 [1.10], cataract surgery alone -0.67 [1.10]) were observed at 24 months. In the baseline IOP ≤18 mmHg subgroup, all cohorts showed significant medication reductions (p<0.001), with no change in IOP. ConclusionsMIGS combined with cataract surgery and cataract surgery alone resulted in significant and sustained IOP (baseline IOP >18mmHg) and medication reductions both IOP subgroups. As MIGS procedures lead to non-equivalent results, further research will define the role of each in patient subpopulations.

Rates of visual field change and functional progression in glaucoma following trabecular microbypass implantation of iStent technologies: a meta-analysis

Background/aimWhile intraocular pressure (IOP) remains the only modifiable risk factor for glaucoma progression, the ultimate goal of glaucoma management is to preserve patients’ functional vision and quality of life. To...

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.

A Comparison of the Effectiveness Between Trabeculectomy and Minimally Invasive Glaucoma Surgeries

Background and Hypothesis: Glaucoma affects 3 million Americans and is the second most common cause of blindness globally, after cataracts. It involves the degeneration of the optic nerve, often associated with increased eye pressure, leading to vision loss. Trabeculectomy was traditionally the standard surgical approach for managing glaucoma progression once medication and laser had failed. Recently, minimally invasive glaucoma surgeries (MIGS) have gained FDA approval for mild and moderate cases and are being implemented in practice. We hypothesize that MIGS procedures are just as effective as trabeculectomy in mild, moderate, and severe cases of glaucoma.&#x0D; Experimental Design or Project Methods: Using data from IU Health, patients that underwent either a MIGS procedure or a trabeculectomy for open-angle glaucoma at least a year ago were identified. Visual field data was used to stage their glaucoma. Any future glaucoma surgery was noted. Using this information, three separate Kaplan-Meier curves at 95% confidence intervals were created corresponding to each stage of glaucoma with a second surgery defined as a failure and a survival analysis was done to visualize the difference between these surgical approaches.&#x0D; Results: The sample included 119 patients and 179 eyes with a mean age of 80 and 57% females. The study had 80% power at a two-sided 5% significance level. Based on the survival analysis, there were no significant differences between trabeculectomy and MIGS in mild and moderate glaucoma (p=0.69 and 0.97 respectively). In severe glaucoma, MIGS had a lower failure rate compared to trabeculectomy (p=0.026).&#x0D; Conclusion and Potential Impact: The research comparing trabeculectomy to MIGS is still relatively new and this study shows the safety and efficacy of MIGS procedures. If confirmed, this study could potentially change the standard of care to MIGS for all stages of open-angle glaucoma.

Combined cataract and glaucoma surgery

Cataracts and glaucoma commonly co‐exist, largely due to both being associated with older age. The crystalline lens can however cause glaucoma by phacomorphic or phacolytic processes, or by contributing to pupil block leading to primary angle closure. Medical and surgical treatments for glaucoma can also result in accelerated cataract formation. Cataract surgery in patients with glaucoma provides an opportunity to reduce medication burden and improve intraocular pressure control but has a higher risk than surgery in non‐glaucomatous eyes. Special consideration should be given to those with pseudoexfoliation (e.g. zonular instability), advanced glaucoma (e.g., risk of pressure spike and wipe out) or in those with short axial length or angle closure (e.g., shallow anterior chamber and risk of malignant glaucoma). Cataract surgery in eyes with previous subconjunctival glaucoma surgery is a particular challenge as it increases the risk of wound healing and failure of the filtering procedure. This presentation will outline steps for success in cataract surgery in patients with glaucoma and will also present recent evidence regarding the efficacy of phacoemulsification combined with minimally invasive glaucoma surgery (MIGS).

Complications of XEN gel stent implantation for the treatment of glaucoma: a systematic review.

This study was aimed to summarize the complications and their management associated with XEN gel stent implantation. A systematic review of literature was conducted using Medline (via PubMed), EMBASE, the Cochrane Library databases, and China National Knowledge Infrastructure, from their inception to February 1, 2024. A total of 48 studies published between 2017 and 2024 were identified and included in the systematic review, including 16 original studies (retrospective or prospective clinical studies), 28 case reports, and 4 case series, which followed patients for up to 5 years. Early postoperative complications of XEN gel stent implantation include hypotony maculopathy (1.9-4.6%), occlusion (3.9-8.8%), suprachoroidal hemorrhage (SCH), choroidal detachment (0-15%), conjunctival erosion, and exposure of the XEN gel stent (1.1-2.3%), wound and bleb leaks (2.1%) and malignant glaucoma (MG) (2.2%). Mid-postoperative complications of XEN gel stent implantation included migration of XEN (1.5%), ptosis (1.2%), endophthalmitis (0.4-3%), macular edema (1.5-4.3%), hypertrophic bleb (8.8%) and subconjunctival XEN gel stent fragmentation (reported in 2 cases). Late postoperative complications reported in cases included spontaneous dislocation and intraocular degradation. XEN gel stent implantation is a minimally invasive glaucoma surgery (MIGS) procedure for glaucoma, known for its potential to minimize tissue damage and reduce surgical duration. However, it is crucial to note that despite these advantages, there remains a risk of severe complications, including endophthalmitis, SCH, and MG. Therefore, postoperative follow-up and early recognition of severe complications are essential for surgical management.

MINIMALLY INVASIVE GLAUCOMA SURGICAL TECHNIQUES FOR OPEN-ANGLE GLAUCOMA : A SYSTEMATIC REVIEW

Background: 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. Methods: By comparing itself to the standards set by the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020, this study was able to show that it met all of the requirements. So, the experts were able to make sure that the study was as up-to-date as it was possible to be. For this search approach, publications that came out between 2013 and 2023 were taken into account. Several different online reference sources, like Pubmed and SagePub, were used to do this. It was decided not to take into account review pieces, works that had already been published, or works that were only half done. Result: In the PubMed database, the results of our search brought up 318 articles, whereas the results of our search on SagePub brought up 34 articles. The results of the search conducted for the last year of 2013 yielded a total 13 articles for PubMed and 12 articles for SagePub. In the end, we compiled a total of 5 papers, 4 of which came from PubMed and 1 of which came from SagePub. We included five research that met the criteria. Conclusion: Although MIGS seem efficient in the reduction of the IOP and glaucoma medication and show good safety profile, this evidence is mainly derived from non-comparative studies and further, good quality RCTs are warranted.

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...

Mise au point de la Société française du glaucome sur la place des nouvelles techniques chirurgicales dans le glaucome

The surgical management of glaucoma has been enriched in recent years by the arrival of new surgical techniques as a group known as MIGS (minimally invasive glaucoma surgery). The objective of these new techniques is to reduce intraocular pressure (IOP) while limiting the risk of complications of conventional filtering surgery and allowing faster visual recovery. MIGS can be classified into three main categories depending on the route used to promote the outflow of aqueous humor: the trabecular route, the suprachoroidal route and the subconjunctival route. MIGS using the subconjunctival route are also called minimally invasive bleb surgery (MIBS). These new techniques do not replace conventional filtering surgery, which remains the gold standard technique, but now offer new alternatives for the surgical management of glaucoma patients in combination with cataract surgery or as stand-alone procedures.

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

ABSTRACT 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.

Recent Advancements in Glaucoma Surgery-A Review.

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

Attaching importance to the health economic evaluation of minimally invasive glaucoma surgery

Compared to traditional filtration surgery, minimally invasive glaucoma surgery (MIGS) offers several advantages, including smaller incisions, more effective intraocular pressure reduction, higher safety levels, fewer surgical complications, faster postoperative recovery, and reduced postoperative use of antiglaucoma drugs. MIGS has gained rapid popularity both domestically and internationally due to its easier operation, shorter learning curve, and reduced operation time. Considering the current clinical promotion of MIGS and the application of health economic evaluation in the glaucoma field, this article proposes the need for an emphasis on the health economic evaluation of MIGS. Conducting research in this area will provide valuable insights for related clinical diagnosis and treatment, medical pricing, and medical insurance payment, and help to further disseminate MIGS, so as to offer clinical benefits, which are aligned with national conditions and economic viability.

Chinese expert consensus on the perioperative management of minimally invasive glaucoma surgery with subconjunctival implants (2023)

Minimally invasive glaucoma surgery (MIGS) is widely used in China because of its effective reduction of intraocular pressure, small incisions, few surgical complications, and quick postoperative recovery. In order to regulate and promote the clinical application of MIGS, the Glaucoma Group of Ophthalmology Branch of Chinese Medical Association has formed consensus opinions on the clinical application and perioperative management of MIGS with subconjunctival implants on the basis of domestic and foreign research results and clinical practice, providing reference and guidance for clinical work.

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.

Position of the ISTENT Inject® Trabecular Micro-Bypass System Visualized with the NIDEK GS-1 Gonioscope-A Postoperative Analysis.

Glaucoma is one of the leading causes of irreversible blindness globally and is characterized by the gradual loss of retinal ganglion cells. The primary risk factor for the development and progression of glaucoma is increased intraocular pressure (IOP). Numerous surgical interventions exist to lower IOP should conservative therapy fail. One trend in recent years has been minimally invasive glaucoma surgery (MIGS) as an alternative to traditional methods. The ISTENT inject® is an ab interno trabecular micro-bypass implant designed to be implanted through the trabecular meshwork into the Schlemm's canal to lower IOP. The aim of the study was the postoperative visualization and description of the positioning of the ISTENT inject® using automated circumferential goniophotography. Patients with symptomatic cataracts and mild to moderate primary open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PEX), and pigment-dispersion glaucoma were included who underwent combined cataract surgery with the ISTENT inject® and received postoperative automated gonioscopy with the NIDEK Gonioscope GS-1 to visualize the location of the implant. Twenty-four implants of 14 eyes in 11 patients could be visualized. Out of the implants, 14.3% were in the trabecular meshwork, 46.4% were at the border between the trabecular meshwork and scleral spur, 25% were below the trabecular meshwork, and 14.3% of the implants were not detectable in the gonioscopy. In the overall cohort, a statistically significant IOP reduction was found over the 12-month postoperative observation period. Even in three eyes, in each of which both stents were located below the trabecular meshwork, an IOP reduction over 12 months was observed compared to the baseline IOP. In this study, vertical two-dimensional positioning of the ISTENT inject® was performed for the first time using NIDKE GS-1 automated 360° goniophotography. The method is suitable for postoperative visualization, control, and documentation of positioning after ISTENT inject® implantation. Further studies are needed to analyze the correlation between positioning of the ISTENT inject® in the chamber angle and postoperative IOP reduction.

Efficacy and Safety Outcomes of XEN Implantation and Gonioscopy-assisted Transluminal Trabeculotomy for the Management of Advanced Open-angle Glaucoma.

Minimally invasive glaucoma surgery (MIGS) is not typically used in patients with advanced-stage glaucoma. This study describes the outcomes and complications of patients with advanced open-angle glaucoma (OAG) who underwent XEN implantation with cataract surgery or gonioscopy-assisted transluminal trabeculotomy (GATT) with cataract surgery. This retrospective study identified patients who had undergone XEN implantation or GATT for the management of advanced OAG. Outcomes included surgical success, intraocular pressure (IOP) reduction, number of topical IOP-lowering drops, visual field mean deviation (MD), best-corrected visual acuity (BCVA), and complications. Surgical success was defined as an IOP of <14 mm Hg and a 20% reduction at 12 months without topical IOP-lowering drops (complete success) or with topical IOP-lowering drops (qualified success). Exactly 70 eyes were enrolled in this study, including 35 who had undergone XEN implantation and 35 who had undergone GATT. The overall surgical success rate was 74.3% (26 of 35) for eyes that underwent XEN implantation and 71.4% (25 of 35) for eyes that underwent GATT. Percent IOP reduction from baseline to 12 months postoperatively was 48% in the XEN cohort and 32% in the GATT cohort. Significant reduction in the use of topical IOP-lowering drops was demonstrated for both XEN (3.26 ± 1.15-1.23 ± 1.28) (p < 0.001) and GATT (2.46 ± 1.12-0.43 ± 0.78) (p < 0.001) cohorts at 12 months postoperatively. The only complication reported was transient hyphema, which occurred in three patients from the XEN group and four from the GATT group, and resolved spontaneously. Both XEN implantation and GATT may be safe and effective management options when treating patients with advanced OAG. However, larger sample sizes are required to make direct statistical comparisons between these techniques. In this study, XEN implantation and GATT combined with cataract surgery were each associated with favorable outcomes in patients with advanced OAG. Ruparelia S, Sharif M, Shoham-Hazon N. Efficacy and Safety Outcomes of XEN Implantation and Gonioscopy-assisted Transluminal Trabeculotomy for the Management of Advanced Open-angle Glaucoma. J Curr Glaucoma Pract 2023;17(2):63-67.