Search

Schlemm's canal (SC) is a small circular canal in the deep part of the sclera at the junction of the sclera and cornea. As an integral component of the aqueous humor outflow, its structure and function are essential in regulating intraocular pressure (IOP). If SC develops lesions, the drainage of aqueous humor would be obstructed, leading to increased intraocular pressure and injury to the optic nerve. With the rapid development of minimally invasive glaucoma surgery, an increasing number of surgeons became familiar with SC, and the area generated substantial academic attention. The pathological mechanism and the therapy for SC that had been studied in recent years are summarized in this article, hoping to provide ideas for the treatment of glaucoma in the future. [ABSTRACT FROM AUTHOR]

Schlemm's canal (SC) is central in intraocular pressure regulation but requires much characterization. It has distinct inner and outer walls, each composed of Schlemm's canal endothelial cells (SECs) with different morphologies and functions. Recent transcriptomic studies of the anterior segment added important knowledge, but were limited in power by SEC numbers or did not focus on SC. To gain a more comprehensive understanding of SC biology, we performed bulk RNA sequencing on C57BL/6 J SC, blood vessel, and lymphatic endothelial cells from limbal tissue (~4,500 SECs). We also analyzed mouse limbal tissues by single-cell and single-nucleus RNA sequencing (C57BL/6 J and 129/Sj strains), successfully sequencing 903 individual SECs. Together, these datasets confirm that SC has molecular characteristics of both blood and lymphatic endothelia with a lymphatic phenotype predominating. SECs are enriched in pathways that regulate cell-cell junction formation pointing to the importance of junctions in determining SC fluid permeability. Importantly, and for the first time, our analyses characterize three molecular classes of SECs, molecularly distinguishing inner wall from outer wall SECs and discovering two inner wall cell states that likely result from local environmental differences. Further, and based on ligand and receptor expression patterns, we document key interactions between SECs and cells of the adjacent trabecular meshwork (TM) drainage tissue. Also, we present cell type expression for a collection of human glaucoma genes. These data provide a new molecular foundation that will enable the functional dissection of key homeostatic processes mediated by SECs as well as the development of new glaucoma therapeutics. [ABSTRACT FROM AUTHOR]

This study aimed to assess the effectiveness and safety of ab externo canaloplasty over a 3-year follow-up period in Polish Caucasian patients with glaucoma. This retrospective study of a cases series was conducted at the Department of Ophthalmology Medical University of Bialystok, Poland. Primary outcome measures were intraocular pressure and medication burden. Secondary outcome measures were best corrected visual acuity, retinal nerve fiber layer thickness, visual field test results, endothelial cell density, intraoperative and postoperative complications, and additional glaucoma surgery. The study group consisted of 160 eyes diagnosed with early to-moderate primary open-angle glaucoma and treated with ab externo canaloplasty from 2014 to 2020. The criteria for qualified and complete success were intraocular pressure < 18 mmHg or ≥ 20% reduction in intraocular pressure from baseline with or without antiglaucoma medications, respectively. After surgery, the mean intraocular pressure decreased from 19.23 ± 4.33 to 14.52 ± 3.79 mmHg, which constituted a 36.7 ± 7.8% reduction compared to the baseline value. The number of medications decreased by two at the end of the study period (from 2.69 ± 1.05 to 0.32 ± 0.75). Complete and qualified success were achieved in 58.7% and 68.7% of the patients, respectively, at the end of follow-up. An incomplete cannulation of Schlemm's canal was the most common intraoperative complication, occurring in 32 eyes (20%). The most frequent postoperative complications were hyphema, Descemet's membrane detachment, and a transient increase in intraocular pressure. Additional surgical procedure was required in seven cases (4.4%). In 16 patients (10%), medical treatment was re-administered. Overall, our findings suggest that ab externo canaloplasty is a good option for Polish Caucasian patients with primary open-angle glaucoma. It reduces intraocular pressure and has a low postoperative complication rate. Additional glaucoma surgery or re-administration of medications is required if the target intraocular pressure is unsatisfactory. [ABSTRACT FROM AUTHOR]

Introduction: Glaucoma, one leading cause of irreversible vision loss worldwide, is primarily caused by elevated intraocular pressure (IOP). Recently, minimally invasive glaucoma surgeries (MIGSs) have become popular due to their shorter surgical times, tissue-sparing nature, and faster recovery. One such MIGS, the Hydrus® nickel–titanium alloy Microstent, helps lower IOP by improving aqueous humor outflow. The NIDEK GS-1 automated 360° gonioscope provides advanced imaging of the chamber angle for evaluation and documentation. The aim of this study was to test automated 360° gonioscopy for the detection of postoperative positional variations after Hydrus® Microstent implantation. This study is the largest to date to evaluate post-op positioning of the Hydrus® Microstent using the NIDEK GS-1. Materials and Methods: This study analyzed postoperative outcomes and stent location in eyes diagnosed with mild to moderate glaucoma that underwent Hydrus® Microstent implantation with or without phacoemulsification. Patients with prior IOP-lowering surgery or vitrectomy were excluded. Analyses of the postoperative Hydrus® Microstent position were based on the evaluation of automated 360° gonioscopy images. Results: Twenty-three eyes were included in the study, and all showed a reduction in IOP and a decrease in antiglaucomatous drop use postoperatively. Postoperative gonoscopic images showed variations in implant position. In all cases, the proximal inlet was clearly visible in the anterior chamber. The degree of protrusion into the anterior chamber was variable. The distal tip of the stent was visible behind the trabecular meshwork in Schlemm's canal in five cases, in the anterior chamber in one case, and not visible in seven cases. In no case did postoperative alterations in the position of the implant lead to explantation. Conclusions: This study demonstrated that the Hydrus® Microstent can effectively lower IOP even in the presence of postoperative positional variations. Automated 360° gonioscopy was found to be a useful tool to verify and document the postoperative position of the implant. Positional changes did not require device explantation in any of the cases evaluated. [ABSTRACT FROM AUTHOR]

Abstract To evaluate the effectiveness and biocompatibility of Wistend, a novel Schlemm’s canal (SC) microstent made of Nitinol designed to improve aqueous humor outflow. New Zealand white (NZW) rabbits were divided into blank, sham-operated and Wistend groups. ICare® Tonovet Plus®, swept-source optical coherence tomography (SS-OCT), slit lamp biomicroscopy, retinal camera and scanning electron microscopy (SEM) were used for preoperative and postoperative observations. Hematoxylin and Eosin (H&E) tissue staining was adopted for biocompatibility. A significant difference in intraocular pressure (IOP) between the Wistend group and the control groups was observed during the six-month follow-up. SS-OCT identified arc line internal reflections within the SC in the anterior chamber angle. Conjunctival congestion and edema gradually diminished in the early stages. No corneal vascularization, no anterior chamber inflammatory response and no significant tissue reactions were noted in any groups. SEM showed the Wistend’s windows and orifices remained clear, encircled by minimal incidental ocular tissue and free from blockage. Histopathological examination revealed no discernible differences between the Wistend-implanted and sham-operated eyes. These in vivo studies demonstrate the effectiveness and biocompatibility of the microstent. Our findings suggest a promising potential for Wistend in significantly reducing IOP and effectively facilitating the outflow of aqueous humor.

Glaucoma is one of the primary causes of blindness worldwide. Canal opening surgery, a type of minimally invasive glaucoma surgery (MIGS) applied in cases of mild to moderate glaucoma, has gained increasing popularity in recent years due to its efficacy in reducing the intraocular pressure, its safety profile, the simplicity of its technique, and the reduced likelihood of compromised vision. Nevertheless, the existing body of histopathological studies remains insufficient for a comprehensive understanding of post-surgical wound healing. Consequently, debates persist among researchers regarding the mechanism through which Schlemm's canal opening surgery reduces the intraocular pressure, as well as the surgical techniques that may impact the outcomes and the factors influencing surgical success. As the history of MIGS is relatively short and lacks sufficient systemic reviews or meta-analyses evaluating the influence of individual factors, this review was conducted to illuminate the disparities in researchers' opinions at the current stage of research. [ABSTRACT FROM AUTHOR]

Murine models are commonly used to study glaucoma, the leading cause of irreversible blindness. Glaucoma is associated with elevated intra-ocular pressure (IOP), which is regulated by the tissues of the aqueous outflow pathway. In particular, pectinate ligaments (PLs) connect the iris and trabecular meshwork (TM) at the anterior chamber angle, with an unknown role in maintenance of the biomechanical stability of the aqueous outflow pathway, thus motivating this study. We conducted histomorphometric analysis and optical coherence tomography-based finite element (FE) modeling on three cohorts of C57BL/6 mice: “young” (2–6 months), “middle-aged” (11–16 months), and “elderly” (25–32 months). We evaluated the age-specific morphology of the outflow pathway tissues. Further, because of the known pressure-dependent Schlemm's canal (SC) narrowing, we assessed the dependence of the SC lumen area on varying IOPs in age-specific FE models over a physiological range of TM/PL stiffness values. We found age-dependent changes in morphology of outflow tissues; notably, the PLs were more developed in older mice compared to younger ones. In addition, FE modeling demonstrated that murine SC patency is highly dependent on the presence of PLs and that increased IOP caused SC collapse only with sufficiently low TM/PL stiffness values. Moreover, the elderly model showed more susceptibility to SC collapse compared to the younger models. In conclusion, our study elucidated the previously unexplored role of PLs in the aqueous outflow pathway, indicating their function in supporting TM and SC under elevated IOP. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to compare iris area, Schlemm's canal, and corneal tomography parameters in patients with unilateral Fuchs uveitis syndrome (FUS) with their unaffected eyes. Materials and Methods: Anterior segment optical coherence tomography (AS-OCT) were performed for sixteen unilateral FUS patients after an ophtalmological examinaton. The iris area was calculated by marking 3 mm from the pupil edge at 3 and 9 o'clock positions. Schlemm's canal length and area were calculated using the device's calipers. All patients underwent corneal tomography. Results: The average age of patients was 43.8±11.3 years. In eyes affected by FUS, there was no significant difference in nasal and temporal iris area, measuring 1.086±0.054 mm² and 0.999±0.059 mm² (p=0.11 and p=0.49). The nasal and temporal Schlemm's canal lengths in affected eyes were 245.4±24.2 µm and 241.3±20.5 µm, and nasal and temporal Schlemm's canal areas were 0.006±0.001 mm² and 0.006±0.001 mm², with no significant difference compared to unaffected eyes (p=0.58, p=0.16, p=0.79, and p=0.64, respectively). Subgroup analysis based on the presence of glaucoma and heterochromia also revealed no significant differences. Corneal tomography parameters were also found similar between the eyes (p>0.05 for all). Conclusion: Our study found similar iris area measurements between affected and unaffected eyes. These results support that iris stromal thickness measured by AS-OCT is not sensitive enough to distinguish affected eye from unaffected eye in unilateral FUS. Remarkably, the histological changes in the Schlemm's canal anatomy, reported in patients with glaucoma in past studies, are not detected in glaucomatous eyes affected by FUS. [ABSTRACT FROM AUTHOR]

Age and elevated intraocular pressure (IOP) are the two primary risk factors for glaucoma, an optic neuropathy that is the leading cause of irreversible blindness. In most people, IOP is tightly regulated over a lifetime by the conventional outflow tissues. However, the mechanistic contributions of age to conventional outflow dysregulation, elevated IOP and glaucoma are unknown. To address this gap in knowledge, we studied how age affects the morphology, biomechanical properties and function of conventional outflow tissues in C57BL/6 mice, which have an outflow system similar to humans. As reported in humans, we observed that IOP in mice was maintained within a tight range over their lifespan. Remarkably, despite a constellation of age‐related changes to the conventional outflow tissues that would be expected to hinder aqueous drainage and impair homeostatic function (decreased cellularity, increased pigment accumulation, increased cellular senescence and increased stiffness), outflow facility, a measure of conventional outflow tissue fluid conductivity, was stable with age. We conclude that the murine conventional outflow system has significant functional reserve in healthy eyes. However, these age‐related changes, when combined with other underlying factors, such as genetic susceptibility, are expected to increase risk for ocular hypertension and glaucoma. [ABSTRACT FROM AUTHOR]

Background: The European Glaucoma Society recommends that selective laser trabeculoplasty (SLT) be considered as a first-line treatment option for patients with mild or moderate primary open-angle glaucoma (POAG) or for those who have not responded well to medications. Purpose: To assess the efficacy of POAG treatment with SLT based on examination of the function of Schlemm's canal (SC) Methods: This paper presents the results of clinical studies and one-month dynamic follow-up of 38 POAG patients (52 eyes) who underwent SLT with a Tango Reflex YAG/SLT laser (Ellex, USA) at the VISUS clinic (Zaporizhzia). Of the 38 patients, 18 (47.37%) were males and 20 (52.63%) females. Patient age ranged from 58 to 85 years (mean age ± standard deviation, 69 ± 9.9 years). Results: There was a significant difference in the response to SLT between eyes with a functional blockage and those with an organic blockage of SC. In the former eyes, true intraocular pressure (P0) decreased from 25.66 ± 0.41 mmHg before SLT to 19.2 ± 0.24 mmHg, outflow facility coefficient increased by 40%, and Becker's coefficient decreased by 46.63% at 1 month after SLT (p < 0.05). In eyes with an organic blockage of SC, P0 changed from 27.69 ± 0.51 mmHg before SLT to 27.64 ± 0.49 mmHg at 1 week, and even increased to 28.75 ± 0.52 mmHg at month 1 after SLT (p 0.05), and tonography characteristics did not change. Conclusion: The current study demonstrated that the success rate of SLT in eyes with POAG was 69.2%. The success rate, however, may reach 100% (with a mean percentage IOP reduction of 25.18%, 40 percent increase in the outflow facility coefficient, and 46.63 percent decrease in the Becker's coefficient) if SLT is performed only in POAG eyes with a functional blockage of SC. If established, the functional state of SC may be used for determining indications and contraindications for SLT in POAG. [ABSTRACT FROM AUTHOR]

Purpose: to investigate secondary glaucoma resulting from uveitis in a patient infected with Human T-cell Leukemia Virus Type 1 (HTLV-1) pathologically and discuss the management of glaucoma with recurrent uveitis. Clinical course: An octogenarian woman diagnosed as a carrier of HTLV-1 experienced recurrent uveitis and a sudden rise in intraocular pressure (IOP) in both eyes. Due to the uncontrolled IOP and severely damaged visual field in her left eye, a combined procedure of trabeculectomy and DGIS (glaucoma drainage implant surgery, Baerveldt 350) was performed. The presence of HTLV-1 provirus was detected in the aqueous humor. Her trabeculectomy sample was processed for light microscopic observation. Following an irregular follow-up, she presented with a sudden decrease in vision and pain in her fellow eye, four years after the glaucoma surgeries. Her right eye exhibited a significant accumulation of mutton-fat-like keratic precipitates. Results: Clinical manifestations revealed the presence of granulomatous uveitis. The combined glaucoma surgery, along with continuous topical corticosteroid medication post-surgery in her left eye, effectively suppressed the high IOP spikes and the recurrence of uveitis for 4 years. The pathological examination of the outflow pathways showed a range of damages in Schlemm's canal (SC), including SC endothelial loss, narrowing, and occlusion, as well as loss of trabecular meshwork (TM) cells and fused TM beams. Conclusion: Combined GDIS and trabeculectomy represents a promising approach for managing such refractory cases of secondary glaucoma. Continuous topical corticosteroid medication is strongly recommended to prevent irreversible changes in SC and TM associated with granulomatous uveitis. [ABSTRACT FROM AUTHOR]

Schlemm’s canal (SC) is central in intraocular pressure regulation but requires much characterization. It has distinct inner and outer walls, each composed of Schlemm’s canal endothelial cells (SECs) with different morphologies and functions. Recent transcriptomic studies of the anterior segment added important knowledge, but were limited in power by SEC numbers or did not focus on SC. To gain a more comprehensive understanding of SC biology, we performed bulk RNA sequencing on C57BL/6 J SC, blood vessel, and lymphatic endothelial cells from limbal tissue (~4,500 SECs). We also analyzed mouse limbal tissues by single-cell and single-nucleus RNA sequencing (C57BL/6 J and 129/Sj strains), successfully sequencing 903 individual SECs. Together, these datasets confirm that SC has molecular characteristics of both blood and lymphatic endothelia with a lymphatic phenotype predominating. SECs are enriched in pathways that regulate cell-cell junction formation pointing to the importance of junctions in determining SC fluid permeability. Importantly, and for the first time, our analyses characterize three molecular classes of SECs, molecularly distinguishing inner wall from outer wall SECs and discovering two inner wall cell states that likely result from local environmental differences. Further, and based on ligand and receptor expression patterns, we document key interactions between SECs and cells of the adjacent trabecular meshwork (TM) drainage tissue. Also, we present cell type expression for a collection of human glaucoma genes. These data provide a new molecular foundation that will enable the functional dissection of key homeostatic processes mediated by SECs as well as the development of new glaucoma therapeutics.

The article discusses a case of reticular bullous epitheliopathy induced by the medication netarsudil 0.02%. The patient, a 46-year-old black woman with advanced glaucoma, experienced corneal subepithelial bullae after starting netarsudil but continued the medication with close monitoring. The bullae resolved without discontinuation of netarsudil, highlighting the importance of balancing risks and benefits when managing patients with ocular hypotensive medications. The article also explores the pathophysiology of this rare adverse event and emphasizes the need for careful monitoring and individualized treatment decisions. [Extracted from the article]

Abstract Digital ocular massage has been reported to temporarily lower intraocular pressure (IOP). This could be related to an enhanced aqueous humor outflow; however, the mechanism is not clearly understood. Using anterior segment optical coherence tomography, the Schlemm’s canal (SC) and trabecular meshwork (TM) can be imaged and measured. Here, 66 healthy adults underwent digital ocular massage for 10 min in their right eyes. The IOP and dimensions of the SC and TM were measured before and after ocular massage. All subjects demonstrated IOP reduction from 15.7 ± 2.5 mmHg at baseline to 9.6 ± 2.2 mmHg immediately after, and median of 11.6 mmHg 5-min after ocular massage (Friedman’s test, p

Background: Minimally invasive glaucoma surgery (MIGS) is a new class of surgeries, which combines moderate to high success rates and a high safety profile. Bent Ab interno Needle Goniotomy (BANG) and Gonioscopy-Assisted Transluminal Trabeculotomy (GATT) are two low-cost MIGS procedures that communicate the anterior chamber to Schlemm's canal. Most of the available publications on MIGS are either case series or retrospective studies, with different study protocols. The aim of this manuscript is to describe a randomized clinical trial (RCT) protocol to compare the long-term intraocular pressure (IOP) control and the safety of both procedures in eyes with primary open-angle glaucoma. Methods: This is a parallel, double-arm, single-masked RCT that includes pseudophakic primary open-angle glaucoma (POAG) eyes. After inclusion criteria, medications will be washed out to verify baseline IOP before surgery. Patients will be randomized to BANG or GATT using a sealed envelope. Follow-up visits will be 1, 7, 15, 30, 60, 90, 180, 330 and 360 days after surgery. On PO330, a new medication washout will be done. The main outcome is the IOP reduction following the procedures. Complimentary evaluation of functional and structural parameters, safety, and quality of life will be done after 30, 90, 180, and 360 days. Discussion: Our study was designed to compare the long-term efficacy and safety of two low-cost MIGS. Most of the published studies on this subject are case series or retrospective cohorts, with different study protocols, which included different types and severities of glaucomas, combined with cataract extraction. Our study only included mild to moderate POAG eyes, with previous successful cataract extraction. Moreover, it provides a standardized protocol that could be replicated in future studies investigating various types of MIGS. This would allow comparison between different techniques in terms of efficacy, safety, and patients' quality of life. Trial registration: Retrospectively registered at the Registro Brasileiro de Ensaios Clínicos (ReBEC) platform RBR-268ms5y. Registered on July 29, 2023. The study was approved by the Ethics Committee of the University of Campinas, Brazil. [ABSTRACT FROM AUTHOR]

The authors report a case of a 5-month-old full-term infant with chronic conjunctival redness and elevated intraocular pressure in the right eye. Magnetic resonance imaging ruled out leptomeningeal angiomatosis. Despite lacking a typical port-wine mark, the diagnosis of Sturge-Weber syndrome was established based on specific observations in the right eye that involved unilateral vascular glaucoma. These findings included Haab striae, a larger axial length measurement, an increased number of episcleral vessels with blood in Schlemm canal, and a thicker choroid in the macular region. This is the first reported pediatric case with these specific ocular manifestations in the absence of facial angioma, highlighting the need for awareness among clinicians to avoid misdiagnosis and facilitate proper management. [J Pediatr Ophthalmol Strabismus. 2024;61(3):e19–e22.] [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of uneventful cataract surgery on Schlemm's canal (SC) and the trabecular meshwork (TM) in cases with pseudoexfoliation (PX). Methods: In this prospective study, 37 PX and 37 normal eyes, who underwent cataract surgery, were included. The PX group was further divided into two subgroups: PX syndrome (PXS) and PX glaucoma (PXG). Preoperative complete ophthalmologic examination, anterior segment (AS) imaging using a Scheimpflug camera, and measurements of SC length and area and TM thickness and length using AS optical coherence tomography (AS-OCT) were performed in all cases. All measurements were repeated at the first and third months after surgery. Results: Preoperative intraocular pressure (IOP), AS parameters, SC, and TM values showed no significant differences between the groups (p > 0.05). After surgery, there was a significant increase in AS parameter values and a significant decrease in IOP values in both the PX and control groups (p < 0.05). The nasal and temporal SC area showed a significant increase in the PX group after surgery (p = 0.007, p = 0.003, respectively). In the subgroup analysis, the only significant change in the nasal and temporal SC area was in the PXS group (p = 0.006, p = 0.003, respectively). Conclusion: Cataract surgery resulted in an increase in the SC area in patients with PXS. This increase may be due to multiple mechanisms including the IOP-lowering effect of cataract removal, change in AS, and removal of intraocular PX material after surgery. [ABSTRACT FROM AUTHOR]

Background: To assess the anterior scleral thickness (AST), Schlemm's canal diameter (SCD), trabecular meshwork diameter (TMD) and conjunctiva tenon capsule thickness (CTT) in high myopic (HM) subjects and HM subjects with glaucoma (HMG) compared to control eyes. Methods: One hundred and twenty eyes were included, and AST at 0, 1, 2 and 3 mm from the scleral spur, SCD, TMD and CTT were measured. Results: Mean age was 64.2 ± 11.0 years, and the temporal SCD and temporal TMD were significantly longer in the HMG subjects compared to the controls (380.0 ± 62 μm vs. 316.7 ± 72 μm, p = 0.001) and (637.6 ± 113 μm vs. 512.1 ± 97 μm, p = 0.000), respectively. There were no significant differences between the HM and HMG subjects in SCD and TMD (all p > 0.025). Compared to the HM subjects, the temporal AST0 (432.5 ± 79 μm vs. 532.8 ± 99 μm, p = 0.000), temporal AST1 (383.9 ± 64 μm vs. 460.5 ± 80 μm, p = 0.000), temporal AST2 (404.0 ± 68 μm vs. 464.0 ± 88 μm, p = 0.006) and temporal AST3 (403.0 ± 80 μm vs. 458.1 ± 91 μm, p = 0.014) were significantly thinner in the HMG group. No differences were found between the CTT in the three groups (all p > 0.025). Conclusions: Our data indicate a thinner AST in HMG subjects and no differences in SCD and TMD between HM and HMG subjects. [ABSTRACT FROM AUTHOR]

Purpose: To predict the presence of angle dysgenesis on anterior-segment optical coherence tomography (ADoA) by using deep learning (DL) and to correlate ADoA with mutations in known glaucoma genes. Participants: In total, 800 high-definition anterior-segment optical coherence tomography (AS-OCT) images were included, of which 340 images were used to build the machine learning (ML) model. Images used to build the ML model included 170 scans of primary congenital glaucoma (16 patients), juvenile-onset open-angle glaucoma (62 patients), and adult-onset primary open-angle glaucoma eyes (37 patients); the rest were controls (n = 85). The genetic validation dataset consisted of another 393 images of patients with known mutations that were compared with 320 images of healthy controls. Methods: ADoA was defined as the absence of Schlemm's canal, the presence of hyperreflectivity over the region of the trabecular meshwork, or a hyperreflective membrane. DL was used to classify a given AS-OCT image as either having angle dysgenesis or not. ADoA was then specifically looked for on AS-OCT images of patients with mutations in the known genes for glaucoma. Results: The final prediction, which was a consensus-based outcome from the three optimized DL models, had an accuracy of >95%, a specificity of >97%, and a sensitivity of >96% in detecting ADoA in the internal test dataset. Among the patients with known gene mutations, (MYOC, CYP1B1, FOXC1, and LTBP2) ADoA was observed among all the patients in the majority of the images, compared to only 5% of the healthy controls. Conclusion: ADoA can be objectively identified using models built with DL. [ABSTRACT FROM AUTHOR]

To determine the intraocular pressure (IOP) reduction of various trabecular procedures (a form of minimally invasive glaucoma surgery [MIGS]) combined with cataract surgery compared with cataract surgery alone, to compare the safety of the various trabecular procedures, and to highlight patient characteristics that may favor one trabecular procedure over another. A search of English-language peer-reviewed literature in the PubMed database was initially conducted in February 2021 and updated in April 2023. This yielded 279 articles. Twenty studies met initial inclusion and exclusion criteria and were assessed for quality by the panel methodologist. Of these, 10 were rated level I, 3 were rated level II, and 7 were rated level III. Only the 10 level I randomized controlled trials (RCTs) were included in this assessment, and all were subject to potential industry-sponsorship bias. The current analysis focuses on the amount of IOP reduction (in studies that involved medication washout) and on IOP reduction with concurrent medication reduction (in studies that did not involve medication washout). Based on studies that performed a medication washout, adding a trabecular procedure to cataract surgery provided an additional 1.6 to 2.3 mmHg IOP reduction in subjects with hypertensive, mild to moderate open-angle glaucoma (OAG) at 2 years over cataract surgery alone, which itself provided approximately 5.4 to 7.6 mmHg IOP reduction. In other words, adding a trabecular procedure provided an additional 3.8% to 8.9% IOP reduction over cataract surgery alone, which itself provided 21% to 28% IOP reduction. There was no clear benefit of one trabecular procedure over another. Patient-specific considerations that can guide procedure selection include uveitis predisposition, bleeding risk, metal allergy, and narrowing of Schlemm's canal. There are no level I data on the efficacy of trabecular procedures in subjects with pretreatment IOP of 21 mmHg or less. Trabecular procedures combined with cataract surgery provide an additional mild IOP reduction over cataract surgery alone in hypertensive OAG subjects. Additional research should standardize outcome definitions, avoid industry sponsorship bias, and study the efficacy of these procedures in normotensive OAG. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article. [ABSTRACT FROM AUTHOR]

PurposeThis study aimed to investigate and compare the anterior scleral thickness (AST) among high myopia (HM), primary open-angle glaucoma (POAG), and POAG with HM (HMPOAG) groups.MethodsThirty-two HM eyes, 30 POAG eyes, and 31 HMPOAG eyes were included. The Schlemm’s canal (SC) area, trabecular meshwork (TM) thickness, scleral spur (SS) length, and AST were measured using swept-source optical coherence tomography. AST was measured at 0 mm (AST0), 1 mm (AST1), 2 mm (AST2), and 3 mm (AST3) from SS.ResultsThe HMPOAG group had significantly thinner AST, SS length, and TM thickness than the HM and POAG groups (all p

In this study we used a spatial transcriptomics approach to identify genes specifically associated with either high or low outflow regions in the trabecular meshwork (TM) that could potentially affect aqueous humor outflow in vivo. High and low outflow regions were identified and isolated from organ cultured human anterior segments perfused with fluorescently-labeled 200 nm FluoSpheres. The NanoString GeoMx Digital Spatial Profiler (DSP) platform was then used to identified genes in the paraffin embedded tissue sections from within those regions. These transcriptome analyses revealed that 16 genes were statistically upregulated in high outflow regions and 57 genes were statistically downregulated in high outflow regions when compared to low outflow regions. Gene ontology enrichment analysis indicated that the top three biological categories of these differentially expressed genes were ECM/cell adhesion, signal transduction, and transcription. The ECM/cell adhesion genes that showed the largest differential expression (Log2FC ±1.5) were ADAM15, BGN, LDB3, and CRKL. ADAM15, which is a metalloproteinase that can bind integrins, was upregulated in high outflow regions, while the proteoglycan BGN and two genes associated with integrin signaling (LDB3, and CRKL) were downregulated. Immunolabeling studies supported the differential expression of ADAM15 and showed that it was specifically upregulated in high outflow regions along the inner wall of Schlemm's canal and in the juxtacanalicular (JCT) region of the TM. In addition to these genes, the studies showed that genes for decorin, a small leucine-rich proteoglycan, and the α8 integrin subunit were enriched in high outflow regions. These studies identify several novel genes that could be involved in segmental outflow, thus demonstrating that digital spatial profiling could be a useful approach for understanding segmental flow through the TM. Furthermore, this study suggests that changes in the expression of genes involved in regulating the activity and/or organization of the ECM and integrins in the TM are likely to be key players in segmental outflow. [ABSTRACT FROM AUTHOR]

Glucocorticoid (GC) therapy is indicated in many diseases, including ocular diseases. An important side-effect of GC therapy is GC-induced ocular hypertension (GIOHT), which may cause irreversible blindness known as GC-induced glaucoma (GIG). Here, we reviewed the pathological changes that contribute to GIOHT including in the trabecular meshwork and Schlemm's canal at cellular and molecular levels. We also discussed the clinical aspects of GIOHT/GIG including disease prevalence, risk factors, the type of GCs, the route of GC administration, and management strategies. [ABSTRACT FROM AUTHOR]

Pathological alterations in the biomechanical properties of the Schlemm’s canal (SC) inner wall endothelium and its immediate vicinity are strongly associated with ocular hypertension in glaucoma due to decreased outflow facility. Specifically, the underlying trabecular meshwork is substantially stiffer in glaucomatous eyes compared with that from normal eyes. This raises the possibility of a critical involvement of mechanotransduction processes in driving SC cell dysfunction. Yes-associated protein (YAP) has emerged as a key contributor to glaucoma pathogenesis. However, the molecular underpinnings of SC cell mechanosignaling via YAP and transcriptional coactivator with PDZ-binding motif (TAZ) in response to glaucomatous extracellular matrix (ECM) stiffening are not well understood. Using a novel biopolymer hydrogel that facilitates dynamic and reversible stiffness tuning, we investigated how ECM stiffening modulates YAP/TAZ activity in primary human SC cells, and whether disruption of YAP/TAZ mechanosignaling attenuates SC cell pathobiology and increases ex vivo outflow facility. We demonstrated that ECM stiffening drives pathologic YAP/TAZ activation and cytoskeletal reorganization in SC cells, which was fully reversible by matrix softening in a distinct time-dependent manner. Furthermore, we showed that pharmacologic or genetic disruption of YAP/TAZ mechanosignaling abrogates stiffness-induced SC cell dysfunction involving altered cytoskeletal and ECM remodeling. Finally, we found that perfusion of the clinically used, small molecule YAP/TAZ inhibitor verteporfin (without light activation) increases ex vivo outflow facility in normal mouse eyes. Collectively, our data provide new evidence for a pathologic role of aberrant YAP/TAZ mechanosignaling in SC cell dysfunction and suggest that YAP/TAZ inhibition has therapeutic value for treating ocular hypertension in glaucoma. NEW & NOTEWORTHY Pathologically altered biomechanical properties of the Schlemm’s canal (SC) inner wall microenvironment were recently validated as the cause for increased outflow resistance in ocular hypertensive glaucoma. However, the involvement of specific mechanotransduction pathways in these disease processes is largely unclear. Here, we demonstrate that Yesassociated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) are central regulators of glaucoma-like SC cell dysfunction in response to extracellular matrix stiffening and that targeted disruption of YAP/TAZ mechanosignaling attenuates SC cell pathobiology and enhances outflow function. [ABSTRACT FROM AUTHOR]

This document is a collection of abstracts from the Asian Journal of Ophthalmology, focusing on various presentations and surgical techniques in the field of ophthalmology. The abstracts cover a range of topics including missing iStents during re-threading, Excimer laser trabeculostomy for glaucoma, management of complex cases involving secondary glaucoma and traumatic cataract, challenges in cataract surgery for nanophthalmic eyes, AGV slicing as an option for failed Ahmed Glaucoma Valves, management of postoperative complications following ICL implantation, dual surgical approach for combined mechanism glaucoma and cataract, and the potential of MIGS techniques to rejuvenate trabeculectomy blebs. These abstracts provide valuable insights for researchers and practitioners in the field of ophthalmology. [Extracted from the article]

aimi,1 Norbert Koerber,2 Simon Ondrejka,2 Mark J Gallardo31Dean McGee Eye Institute – Oklahoma Health Center, Oklahoma City, OK, USA; 2Augencentrum Köln, Köln, Germany; 3El Paso Eye Surgeons, PA, El Paso, TX, USA Correspondence: Mahmoud A Khaimi, Dean McGee Eye Institute – Oklahoma Health Center, 608 Stanton L Young Blvd, Oklahoma City, OK, 73104, USA, Tel +1 405-271-6060, Email [email protected] Purpose: To study the consistency in outcomes of standalone canaloplasty performed via an ab-interno surgical technique in reducing intraocular pressure (IOP) and number of medications in uncontrolled open-angle glaucoma (OAG) eyes over a 12-month period. Methods: This retrospective multicenter case series included patients who underwent standalone canaloplasty via an ab-interno surgical technique using the iTrack microcatheter (Nova Eye, Inc., Fremont, USA) and had preoperative uncontrolled OAG (IOP≥ 18mmHg) along with no previous glaucoma surgery. The iTrack microcatheter is used to circumnavigate 360° and viscodilate Schlemm's canal. Consistency of IOP and medications reduction on an eye-by-eye basis were evaluated to understand the outcomes in each single eye. Results: Sixty-four eyes of 60 patients (age 71.5± 13.4 years) were included. Six eyes (9%) that underwent additional glaucoma surgery were considered a failure and were subsequently excluded from analysis. At 12 months, IOP was reduced in 57 of the 58 (89%) remaining eyes; one eye had the same IOP with a reduced number of medications. Of the 57/58 eyes with a reduced IOP: 44 eyes (69%) required fewer medications; 12 eyes (19%) required the same number of medications. Of these 58 eyes, 78% of eyes had a ≥ 20% reduction in IOP compared to baseline; 69% eyes had a postoperative IOP ≤ 15 mmHg, and 86% eyes ≤ 18 mmHg at 12 months. Forty percent of the eyes were medication-free at 12 months compared to none at baseline. Conclusion: Canaloplasty performed via an ab-interno surgical technique as a standalone procedure consistently reduced IOP and glaucoma medications in almost all eyes. [ABSTRACT FROM AUTHOR]

Introduction: Glaucoma is one of the leading cause of irreversible blindness worldwide. Among the affected ones, approximately 50% are not aware of it, because of its asymptomatic nature, especially in the early stages. Ripasudil Hydrochloride Hydrate is a novel drug, being the Rho-associated coiled-coil- containing protein kinase (ROCK) inhibitor eye drop that increases conventional aqueous outflow through the trabecular meshwork and Schlemm’s canal and thus lowers the intraocular pressure. Material and Methods: This prospective study included the first 150 consecutive eyes in patients of uncontrolled glaucoma with IOP > 21 mmHg despite maximal topical anti-glaucoma medications in at least one eye and aged eighteen or above. The patients with neovascular glaucoma, closed or barely open anterior chamber angle or with history of ocular surgery including refractive surgery were excluded. The purpose and nature of the study were explained in detail, and informed consent was obtained from all patients. Results: This study included 115 patients with 150 affected eyes. The mean age of patients in this series was 43.6 years with a range of 24-73 years. Right eye was affected in 47, left in 33 patients and the remaining 35 patients had bilateral involvement. The mean pachymetry was 521.13 μm in right eye and 523.53 μm in left eye and the mean cup disc ratio was 0.8 and 0.7 in right and left eye respectively. The mean baseline intraocular pressure in our series was 18.60 mmHg +- 7.60 mmHg. The mean IOP at six month follow up visit (final follow-up) was 11.83mmHg +- 4.45, which was statistically significant. The mean reductions in IOP at one month was 12.64mmHg, at 3 months follow up 12.07mmHg. Conclusion: The results of our study implies that ripasudil is a favourable anti glaucoma drug that can lower intraocular pressure. The additive pressure lowering effects of ripasudil in addition to existing maximal therapy can be because of different mechanism of action, it can delay or evade surgery in glaucoma. Transient conjunctival hyperaemia, not necessitating discontinuation was the most common complication in this series. [ABSTRACT FROM AUTHOR]

Purpose: To present the modified surgery technique of new suture probe canaloplasty with a specially prepared monofilament 4.0 polypropylene suture combined with suprachoroidal drainage (ScD) and collagen sheet implantation for non-penetrating glaucoma surgery. Methods: Prospective study with a twelve months follow-up. A standard 4/0 polypropylene suture (ProleneTM by Ethicon; thickness: approximately 250 m) is cut and shaped with an ophthalmic knife (MANI® Crescent Knife, Mani Inc 8-3 Kiyohara Industrial Park, Utsunomiya, Tochigi 321-3231, Japan) to create a blunt end without sharp or compressed edges. This improves suture probe canaloplasty by providing a more stable and smoother probing device. Schlemm’s canal is prepared using the standard technique of canaloplasty with suprachoroidal drainage. Then, instead of using the canaloplasty microcatheter or the previously published 6/0 double-helix suture, Schlemm’s canal is probed with the blunt ending of the 4/0 Prolene suture. After successful 360-degree probing, a doubled 10/0 polypropylene tension suture is threaded through the tip of the 4/0 suture. The 4/0 suture is then pulled back and the 10/0 tension sutures are tied at both ends to tension Schlemm’s canal. A special collagen sheet (Ologen®) is placed in suprachoroidal space, and the scleral flap is firmly sewed. Results: 115 eyes were included in this prospective study. In 113 cases the Schlemm’s canal could completely be probed with the suture probe and canaloplasty with ScD and collagen sheet implantation succeeded. In two cases the intervention was transformed to 360-degree suture trabeculotomy due to an intraoperative cheese-wiring. Twelve months after successful new suture probe canaloplasty with ScD and Collagen Implantation the IOP had decreased by 37.1% (from 21.6 ± 6.0 mmHg with 3.3 different IOP lowering eye drops to 13.5 ± 3.5 mmHg with 1.0 eye drops). 16 Patients did not achieve sufficient IOP levels and underwent 360-degree suture trabeculotomy during the follow-up. One patient had to be treated with further glaucoma surgery to achieve a sufficient IOP level. Complications were hyphema, postoperative IOP elevation and transient hypotony. No serious or sight-threatening complications occurred. Conclusion: New suture probe canaloplasty with ScD and collagen sheet implantation yields the opportunity to conduct a cost-effective canaloplasty easier and less complicated than with the previously described method with the twisted 6/0 suture. The safety profile and IOP lowering effect is comparable. In cases where complete probing fails, there is still the opportunity to switch to suture trabeculotomy over the majorly probed part of Schlemm’s canal. The pressure lowering effect of the deep sclerectomy with ScD and suprachoroidal collagen sheet implant seems to have an additional impact on the sufficient pressure lowering procedure. [ABSTRACT FROM AUTHOR]

This review highlights the importance of extracellular matrix (ECM) biomaterials in understanding the biology of human trabecular meshwork (TM) and Schlemm's canal (SC) cells under normal and simulated glaucoma-like conditions. We provide an overview of recent progress in the development and application of state-of-the-art 3D ECM biomaterials including cell-derived ECM, ECM scaffolds, Matrigel, and ECM hydrogels for studies of TM and SC cell (patho)biology. Such bioengineered platforms enable accurate and reliable modeling of tissue-like cell-cell and cell-ECM interactions. They bridge the gap between conventional 2D approaches and in vivo/ex vivo models, and have the potential to aid in the identification of the causal mechanism(s) for outflow dysfunction in ocular hypertensive glaucoma. We discuss each model's benefits and limitations, and close with an outlook on future directions.

PurposeThe purpose of this study was to investigate femtosecond laser trabeculotomy (FLT) in a clinically relevant manner (i.e., delivering the surgical laser beam through the cornea of the intact, human anterior segment to create channels from the anterior chamber into the Schlemm's canal) and to investigate the effect of this treatment on intraocular pressure in perfused human anterior segments.MethodsPerfused human anterior segments (15 eyes) received either FLT treatment (n = 8) or a sham-treatment (n = 7). Intraocular pressure (IOP) in the perfused samples was recorded before and after treatment. Spectral domain optical coherence tomography, second harmonic generation imaging, and transmission electron microscopy were used to investigate the FLT channels.ResultsThe FLT group (n = 7, 1 eye excluded) had a statistically significant reduction in mean IOP of 20.2% from baseline after treatment (5.06 ± 1.46 mm Hg to 4.04 ± 1.63 mm Hg; P < 0.0005), whereas the control group (n = 7) remained statistically unchanged (7.72 ± 3.45 mm Hg to 7.78 ± 3.51 mm Hg; P < 0.71). Imaging confirmed that the channels traversed the entire trabecular meshwork into the Schlemm's canal.ConclusionsThis study has provided the first direct evidence supporting the feasibility of clinically applicable, noninvasive femtosecond laser trabeculotomy for the treatment of glaucoma. Various imaging modalities revealed minimal collateral damage to adjacent issues.Translational relevanceThis work demonstrates noninvasive femtosecond laser trabeculotomy in a laboratory setting that is clinically relevant.

Abstract Purpose To perform an in vivo evaluation of the changes in Schlemm’s canal (SC) among patients with primary angle-closure disease (PACD) using swept-source optical coherence tomography (SS-OCT). Methods Patients diagnosed with PACD who had not undergone surgery were recruited. The SS-OCT quadrants scanned herein included the nasal and temporal sections at 3 and 9 o’clock, respectively. The diameter and cross-sectional area of the SC were measured. A linear mixed-effects model was performed to analyze the effects of parameters on the SC changes. The hypothesis of interest was related to the angle status (iridotrabecular contact, ITC/open angle, OPN), which was further explored with pairwise comparisons of the estimated marginal means (EMMs) of the SC diameter and SC area. In the ITC regions, the relationship between the trabecular-iris contact length (TICL) percentage and SC parameters was also studied by a mixed model. Results A total of 49 eyes of 35 patients were included for measurements and analysis. The percentage of observable SCs in the ITC regions was only 58.5% (24/41), whereas it was 86.0% (49/57) in the OPN regions (χ2 = 9.44, p = 0.002). ITC was significantly associated with a decreasing SC size. The EMMs for the diameter and cross-sectional area of SC at the ITC and OPN regions were 203.34 μm versus 261.41 μm (p = 0.006) and 3174.43 μm2 versus 5347.63 μm2 (p = 0.022), respectively. Sex, age, spherical equivalent refraction, intraocular pressure, axial length, extent of angle closure, history of acute attack and treatment with LPI were not significantly associated with SC parameters. In the ITC regions, a larger TICL percentage was significantly associated with a decrease in SC diameter and area (p = 0.003 and 0.019, respectively). Conclusions The morphologies of SC could be affected by the angle status (ITC/OPN) in patients with PACD, and ITC was significantly associated with a decreasing SC size. These changes in SC as described by OCT scans might help to elucidate the progression mechanisms of PACD.

Isabella V Wagner,1 Bryan Ang,2 Leticia Checo,1 Derya Simsek,3 Christian Draper,1 Syril Dorairaj1 1Department of Ophthalmology, Mayo Clinic, Jacksonville, FL, USA; 2Department of Ophthalmology, Tan Tock Seng Hospital, Singapore; 3Department of Ophthalmology, Baskent University Medical School, Ankara, TurkeyCorrespondence: Syril Dorairaj, Department of Ophthalmology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, USA, Tel +1 904-953-2377, Fax +1 904-953-7040, Email dorairaj.syril@mayo.eduAbstract: Minimally invasive glaucoma surgery (MIGS) has revolutionized glaucoma care with its favorable safety profile and ability to delay or minimize the need for traditional, bleb-based procedures. Microstent device implantation is a type of angle-based MIGS, which reduces intraocular pressure (IOP) through bypass of the juxtacanalicular trabecular meshwork (TM) and facilitation of aqueous outflow into the Schlemm’s canal. Although there are limited microstent devices on the market, multiple studies have evaluated the safety and efficacy of iStent® (Glaukos Corp.), iStent Inject® (Glaukos Corp.), and Hydrus® Microstent (Alcon) in the treatment of mild-to-moderate open-angle glaucoma, with and without concurrent phacoemulsification. This review attempts to provide a comprehensive evaluation of injectable angle-based microstent MIGS devices in the treatment of glaucoma.Keywords: microstent injection, Schlemm’s canal, Hydrus microstent, iStent, glaucoma, aqueous outflow

The Schlemm’s canal (SC) is a circular, lymphatic-like vessel located at the limbus of the eye that participates in the regulation of aqueous humor drainage to control intraocular pressure (IOP). Circumferential flow of aqueous humor within the SC lumen generates shear stress, which regulates SC cell behaviour. Using biochemical analysis and real-time live cell imaging techniques, we have investigated the activation of autophagy in SC cells by shear stress. We report, for the first time, the primary cilium (PC)-dependent activation of autophagy in SC cells in response to shear stress. Moreover, we identified PC-dependent shear stress-induced autophagy to be positively regulated by phosphorylation of SMAD2 in its linker and C-terminal regions. Additionally, SMAD2/3 signaling was found to transcriptionally activate LC3B, ATG5 and ATG7 in SC cells. Intriguingly, concomitant to SMAD2-dependent activation of autophagy, we also report here the activation of mTOR pathway, a classical autophagy inhibitor, in SC cells by shear stress. mTOR activation was found to also be dependent on the PC. Moreover, pharmacological inhibition of class I PI3K increased phosphorylation of SMAD2 at the linker and activated autophagy. Together, our data indicates an interplay between PI3K and SMAD2/3 signaling pathways in the regulation of PC-dependent shear stress-induced autophagy in SC cells.

Purpose: To compare the morphological characteristics of Schlemm's canal (SC) in patients with primary open-angle glaucoma (POAG) and healthy controls, using swept-source optical coherence tomography (SS-OCT) with en face reconstruction. Methods: In this Prospective comparative study, we included 100 eyes from 50 patients diagnosed with POAG and 50 healthy controls. Three-dimensional cube and line scans of the temporal and nasal quadrants of the anterior segment of the limbus were acquired using SS-OCT. SC was identified using en face and cross-sectional images. The diameter and area of SC in cross-sectional images and the visible percentage and area of SC in en face images were measured using ImageJ. Results: SC was observed in 84% of en face images and 81% of cross-sectional images in eyes with POAG but in 92% of en face images and 86% of crosssectional images in control eyes. Significant differences between the POAG and normal control eyes were found in the en face area (0.35 ± 0.14mm² vs. 0.56 ± 0.22mm² in the temporal quadrant and 0.36 ± 0.14mm² vs. 0.58 ± 0.23mm² in the nasal quadrant; both p < 0.001) and visible percentage of SC (85.71% vs. 94.91% and 87.10% vs. 95.52% in the temporal and nasal quadrant respectively, both p < 0.001) in en face images as well as the cross-sectional area (2790.9 ± 942.2 µm² vs. 4138.6 ± 2027.8 µm² in the temporal quadrant and 2805.7 ± 947.2 µm² vs. 4224.0 ± 2002.2 µm² in the nasal quadrant, both p < 0.001) and diameter of SC (123.1 ± 25.4 µmvs. 149.5 ± 34.7 µmin the temporal quadrant and 126.3 ± 28.9 µm vs. 155.3 ± 36.0 µmin the nasal quadrant, both p < 0.001) in cross-section images. In addition, the mean intraocular pressure (IOP) significantly correlated with the en face area, visible percentage of SC, and cross-sectional area in the temporal and nasal quadrants. Conclusion: SS-OCT can obtain high-quality en face images of SC without postacquisition processing. Eyes with POAG had a decreased en face SC area compared with normal eyes. A correlation between SC area, visible percentage of en face images, and IOP was also observed. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effectiveness of ab-externo canaloplasty using the iTrack canaloplasty microcatheter (Nova Eye Inc, Fremont, California), with or without suture, in glaucoma patients with high myopia. Methods: This was a prospective, single-center, single-surgeon, observational study comparing the outcomes of ab-externo canaloplasty performed with a tensioning suture (suture group) and without a tensioning suture (no-suture group) in mild to severe glaucoma patients with high myopia. Twenty-three eyes received canaloplasty as a standalone procedure, 5 in combination with phacoemulsification. Primary efficacy endpoints included intraocular pressure (IOP) and the number of glaucoma medications. Safety was assessed based on reported complications and adverse events. Results: Twenty-nine eyes of 29 patients with a mean age of 61.2 ± 12.3 years; 19 eyes in the no-suture group and 10 eyes in the suture group. All eyes demonstrated a significant reduction in IOP 24 months postoperatively, from 21.9 ± 7.22 to 15.4 ± 4.86 mmHg in the suture group and from 23.8 ± 7.58 to 19.7 ± 3.68 mmHg in the no-suture group. The mean number of anti-glaucoma medications reduced from 3.1 ± 0.6 to 0.4 ± 0.7 in the suture group and 3.3 ± 0.9 to and 0.2 ± 0.6 in the no-suture group at 24 months. IOP was not significantly different at baseline between the 2 groups, but it was statistically different at 12 and 24 months. There was no statistically significant difference in the number of medications between the groups at baseline, 12 and 24 months. No serious complications were reported. Conclusion: Ab-externo canaloplasty performed either with or without a tensioning suture demonstrated good effectiveness in highly myopic eyes with a significant reduction in IOP and number of anti-glaucoma medications. The suture group achieved a lower postoperative IOP. However, the no-suture modification provides a similar reduction in medications with reduced tissue handling. [ABSTRACT FROM AUTHOR]

Background: More than ~70% of the aqueous humor exits the eye through the conventional aqueous outflow pathway that is comprised of the trabecular meshwork (TM), juxtacanalicular tissue (JCT), the inner wall endothelium of Schlemm's canal (SC). The flow resistance in the JCT and SC inner wall basement membrane is thought to play an important role in the regulation of the intraocular pressure (IOP) in the eye, but current imaging techniques do not provide enough information about the mechanics of these tissues or the aqueous humor in this area. Methods: A normal human eye was perfusion-fixed and a radial wedge of the TM tissue from a high-flow region was dissected. The tissues were then sliced and imaged using serial block-face scanning electron microscopy. Slices from these images were selected and segmented to create a 3D finite element model of the JCT and SC cells with an inner wall basement membrane. The aqueous humor was used to replace the intertrabecular spaces, pores, and giant vacuoles, and fluid–structure interaction was employed to couple the motion of the tissues with the aqueous humor. Results: Higher tensile stresses (0.8-kPa) and strains (25%) were observed in the basement membrane beneath giant vacuoles with open pores. The volumetric average wall shear stress was higher in SC than in JCT/SC. As the aqueous humor approached the inner wall basement membrane of SC, the velocity of the flow decreased, resulting in the formation of small eddies immediately after the flow left the inner wall. Conclusions: Improved modeling of SC and JCT can enhance our understanding of outflow resistance and funneling. Serial block-face scanning electron microscopy with fluid–structure interaction can achieve this, and the observed micro-segmental flow patterns in ex vivo perfused human eyes suggest a hypothetical mechanism. [ABSTRACT FROM AUTHOR]

This article presents three cases of Descemet's membrane detachment (DMD) occurring during 'ab externo' phacocanaloplasty procedures in three patients with uncontrolled primary open-angle glaucoma (OAG) and discusses the management of this condition by reviewing the available literature. Following a successful 360° cannulation of Schlemm's canal (SC), the microcatheter was withdrawn while an ophthalmic viscosurgical device (OVD) was injected into the canal. During passage through the inferonasal quadrant, a spontaneous separation of the posterior layer of the cornea was observed. Each case was managed differently after diagnosis, with the third case being drained intraoperatively based on experience gained from the previous cases. On the first postoperative day, slit-lamp biomicroscopy (BMC) revealed multiple DMDs in case one and a hyphema in the lower third of a deep anterior chamber. In the other two cases, a single DMD was observed. The second case developed hemorrhagic Descemet membrane detachment (HDMD), while the other two were non-hemorrhagic. In all three cases, anterior segment optical coherence tomography (AS-OCT) revealed the presence of retrocorneal hyperreflective membranes indicative of DMDs. These membranes were located in the periphery of the cornea and did not impact the visual axis. After evaluation, a small incision was made in the inferotemporal DMD of the first case. However, for the two remaining cases, a strategy of watchful waiting was deemed appropriate due to the location and size of the DMDs, as they did not affect the best-corrected visual acuity (BCVA). Over time, the patients demonstrated progressive improvement with a gradual reduction in the size of the DMDs. [ABSTRACT FROM AUTHOR]

Background: To assess the anterior scleral thickness (AST), Schlemm’s canal diameter (SCD), trabecular meshwork diameter (TMD) and conjunctiva tenon capsule thickness (CTT) in high myopic (HM) subjects and HM subjects with glaucoma (HMG) compared to control eyes. Methods: One hundred and twenty eyes were included, and AST at 0, 1, 2 and 3 mm from the scleral spur, SCD, TMD and CTT were measured. Results: Mean age was 64.2 ± 11.0 years, and the temporal SCD and temporal TMD were significantly longer in the HMG subjects compared to the controls (380.0 ± 62 μm vs. 316.7 ± 72 μm, p = 0.001) and (637.6 ± 113 μm vs. 512.1 ± 97 μm, p = 0.000), respectively. There were no significant differences between the HM and HMG subjects in SCD and TMD (all p > 0.025). Compared to the HM subjects, the temporal AST0 (432.5 ± 79 μm vs. 532.8 ± 99 μm, p = 0.000), temporal AST1 (383.9 ± 64 μm vs. 460.5 ± 80 μm, p = 0.000), temporal AST2 (404.0 ± 68 μm vs. 464.0 ± 88 μm, p = 0.006) and temporal AST3 (403.0 ± 80 μm vs. 458.1 ± 91 μm, p = 0.014) were significantly thinner in the HMG group. No differences were found between the CTT in the three groups (all p > 0.025). Conclusions: Our data indicate a thinner AST in HMG subjects and no differences in SCD and TMD between HM and HMG subjects.

A study conducted by researchers investigated the effect of wearing a surgical mask on intraocular pressure (IOP) during the COVID-19 pandemic. The study involved 174 participants, including individuals with glaucoma and those without. The results showed that wearing a surgical mask caused a statistically significant increase in IOP, regardless of age, gender, or glaucoma diagnosis. Men were found to be more vulnerable to the effect of surgical masks on IOP values than women. The study suggests that masks should be used properly in certain circumstances to avoid unsatisfactory IOP values in glaucoma patients, but further research is needed to understand the long-term effects of mask-wearing on glaucoma progression and the underlying biological processes. [Extracted from the article]

Background: The mechanism that could increase intraocular pressure (IOP) during scleral lens (SL) wear is not fully understood, although it may be related to compression of the landing zone on structures involved in aqueous humor drainage. Methods: Thirty healthy subjects were fitted with two SLs of different sizes (L1 = 15.8 mm, L2 = 16.8 mm) for 2 h in the right eye and left eye as a control. Central corneal thickness (CCT), parameters of iridocorneal angle (ICA), Schlemm's canal (SC), and optic nerve head were measured before and after wearing both SLs. IOP was measured with a Perkins applanation tonometer before and after lens removal and with a transpalpebral tonometer before, during (0 h, 1 h, and 2 h), and after lens wear. Results: CCT increased after wearing L1 (8.10 ± 4.21 µm; p < 0.01) and L2 (9.17 ± 4.41 µm; p < 0.01). After L1 removal, the ICA parameters decreased significantly (p < 0.05). With L2 removal, nasal and temporal SC area and length were reduced (p < 0.05). An increased IOP with transpalpebral tonometry was observed at 2 h of wearing L1 (2.55 ± 2.04 mmHg; p < 0.01) and L2 (2.53 ± 2.22 mmHg; p < 0.01), as well as an increased IOP with Perkins applanation tonometry after wearing L1 (0.43 ± 1.07 mmHg; p = 0.02). Conclusions: In the short term, SL resulted in a slight increase in IOP in addition to small changes in ICA and SC parameters, although it did not seem to be clinically relevant in healthy subjects. [ABSTRACT FROM AUTHOR]