Angle-based minimally invasive glaucoma surgery in normal tension glaucoma: A systematic review and meta-analysis.

BACKGROUND: This systematic review and meta-analysis quantitatively examines the efficacy of angle-based minimally invasive glaucoma surgery (MIGS) in normal tension glaucoma (NTG). METHODS: A literature search was performed on Medline, Embase, PubMed, CINAHL and Cochrane Library from inception until 20 December 2022. Pilot, cohort, observational studies and randomised controlled trials including at least 5 subjects undergoing angle-based MIGS (trabecular-bypass devices, excisional trabeculotomy, goniotomy and ab-interno canaloplasty) for NTG, with or without cataract surgery, were included. Meta-analysis of continuous outcome using the meta routine in R version 2022.12.0+353 was performed to determine mean intraocular pressure (IOP) and anti-glaucoma medication (AGM) reduction post-operatively. RESULTS: Of the 846 studies initially identified, 15 studies with a pooled total of 367 eyes which underwent combined phacoemulsification and angle-based MIGS were included for final meta-analysis. Outcomes of the iStent were reported in 5 studies, iStent inject in 7 studies, Hydrus Microstent in 1 study, Kahook Dual Blade in 3 studies, and Trabectome in 2 studies. There was significant reduction in both IOP and AGM post-operatively at 6 months (2.44 mmHg, 95%CI: 1.83-3.06; 1.21 AGM, 95%CI: 0.99-1.44), 12 months (2.28 mmHg, 95%CI: 1.71-2.84; 1.18 AGM, 95%CI: 0.90-1.47), 24 months (2.10 mmHg, 95%CI: 1.51-2.68; 1.26 AGM, 95%CI: 0.85-1.68) and 36 months (2.43 mmHg, 95%CI: 1.71-3.15, 0.87 AGM, 95%CI: 0.21-1.53) (all p < 0.05). Subgroup analysis on combined phacoemulsification-iStent inject surgery demonstrated a reduction in both IOP (2.31 mmHg, 95%CI: 1.07-3.56, p < 0.001) and AGM (1.07 AGM, 95%CI: 0.86-1.29, p < 0.001) at 12 months post-operatively. CONCLUSIONS: Angle-based MIGS combined with phacoemulsification effectively reduces IOP and AGM in NTG eyes for up to 36 months after surgery.

Assessing the value of the water drinking test in glaucoma-a systematic review and meta-analysis.

This systematic review and meta-analysis examines the relationship between intraocular pressure (IOP) parameters derived from the water drinking test (WDT) and diurnal IOP monitoring, and evaluates the reproducibility of the WDT and its association with future glaucomatous visual field (VF) loss. A literature search was performed on PubMed, EMBASE, and Cochrane Library from inception to 31 March 2023. Cohort, cross-sectional and observational studies reporting WDT results in glaucoma patients were included. Meta analysis with random-effect model was performed using "metafor" package in R version 3.2.1. 641 studies were identified on initial literature search. 38 studies (2479 subjects) were included in final analysis. Meta-analytic estimates of 5 studies (310 subjects) found strong positive correlation in peak IOP between the WDT and diurnal IOP monitoring (r = 0.92, 95% CI = 0.75, 1.08, p < 0.0001). However, there was only weak positive correlation for IOP fluctuation between both methods (r = 0.26, 95% CI = 0.06,0.47, p < 0.0001). Meta-analytic estimates of 3 studies (189 subjects) suggested a trend of the diurnal peak IOP being lower than that derived from the WDT (MD = -2.37 mmHg, 95% Limit of Agreement (LOA) =-5.58,0.84, p = 0.147). Two studies found that a higher WDT peak IOP was associated with greater future VF progression. Two studies demonstrated good reproducibility in peak IOP measurements for WDTs conducted across different days. In conclusion, there was a strong positive correlation between IOP peak measurements from the WDT and diurnal IOP monitoring in glaucoma patients. The WDT peak IOP demonstrated good reproducibility and may be associated with greater future VF progression.

Effect of anti-VEGF on retinal blood flow in diabetic mice using laser speckle flowgraphy.

PURPOSE: To assess intra- (repeatability) and inter-observer (reproducibility) variability of laser speckle flowgraphy (LSFG) for retinal blood flow (RBF) measurement in 20 eyes of wild type (C57BL/6J) mice and effect of intravitreal Aflibercept on RBF in optic nerve head (ONH) region of 10 eyes of Ins2 (Akita) diabetic mice. METHODS: 'Mean blur rate (MBR)' was measured for all quadrants of tissue area (MT), vessel (MV) and total area (MA) of ONH region. Changes in MT were analysed at each timepoint. Repeatability was evaluated by measuring MBR variability without changing mouse head position, and reproducibility after resetting mouse head position by another operator. Coefficient of repeatability (CR) through Bland-Altman plot method coefficient of variation (COV) and Intraclass correlation coefficient (ICC) was calculated. Intravitreal Aflibercept (1 µg) was administered to Akita eyes and intraocular pressure (IOP) was measured using a tonometer at baseline, day 7, 14, 21 and 28 post-injection. Hurvich and Tsai's criterion was used. RESULTS: Coefficient of repeatability values of repeatability and reproducibility for all quadrants were within limits of agreement. Reliability was excellent (ICC 0.98-0.99) and reproducibility was moderate to excellent (ICC 0.64-0.96). There was a non-significant IOP increase in all Akita eyes at Day 28 (p > 0.05), and significant increase in MT in all quadrants at Day 21 and superior, inferior and temporal quadrants at Day 28 (p < 0.05). CONCLUSION: Laser speckle flowgraphy demonstrates excellent repeatability and moderate to excellent reproducibility in measuring RBF. Intravitreal Aflibercept injection results in a significant increase in MT up to 28 days post-injection without significant increase in IOP.

Aqueous humour protein dysregulation in Asian eyes with primary open angle glaucoma.

The pathophysiology of Primary Open Angle Glaucoma (POAG) remains poorly understood. Through proteomic analysis of aqueous humour (AH) from POAG patients, we aim to identify changes in protein composition of these samples compared to control samples. High resolution mass spectrometry-based TMT6plex quantitative proteomics analysis is performed on AH samples collected from POAG patients, and compared against a control group of patients with cataracts. Data are available via ProteomeXchange with identifier PXD033153. 1589 proteins were quantified from the aqueous samples using Proteome Discoverer version 2.2 software. Among these proteins, 210 were identified as unique master proteins. The proteins which were up or down-regulated by ±3 fold-change were considered significant. Human neuroblastoma full-length cDNA clone CS0DD006YL02 was significantly upregulated in patients with severe POAG on >2 medications, while actin, cytoplasmic 1, V2-7 protein (fragment), immunoglobulin-like polypeptide 1 and phosphatidylethanolamine-binding protein 4 were only present in these patients with severe POAG on >2 medications. Beta-crystallin B1 and B2, Gamma-crystallin C, D and S were significantly downregulated in the severe POAG ≤2 glaucoma medications group. Beta-crystallin B2, Gamma-crystallin D and GCT-A9 light chain variable region (fragment) were significantly downregulated in the non-severe POAG group. Actin, cytoplasmic 1 was significantly upregulated in subjects with severe POAG who required more than 2 glaucoma medications. Crystallins (Beta-crystallin B1 and B2, Gamma-crystallin C, D and S) were significantly downregulated in subjects with severe POAG who required less than 2 glaucoma medications.

A deep dive into hyperbaric environments and intraocular pressure-a systematic review.

Purpose: SCUBA diving exposes participants to a unique hyperbaric environment, but few studies have examined the effects of such an environment on intraocular pressure (IOP) and glaucoma. This systematic review aims to consolidate recent literature findings regarding the impact of increased atmospheric pressure on IOP and glaucoma. Methods: Three online databases were searched to identify publications encompassing the subjects of diving or increased atmospheric pressure in conjunction with IOP or glaucoma. Three reviewers independently screened the publications and identified eligible articles. Relevant data was extracted from each article. The heterogeneity of the data precluded the conduct of a meta-analysis. Results: Nine studies met the inclusion criteria. Six experimental studies employed hyperbaric chambers to measure IOP under simulated diving conditions. Among these, IOP exhibited a reduction with increased atmospheric pressures in four studies, while the findings of two studies were inconclusive. One study measured IOP pre- and post-dive and another measured IOP with and without a diving mask. Post-dive, a decrease in IOP was observed, and a statistically significant reduction was noted when subjects wore a diving mask. A retrospective study examining the incidence of acute angle closure glaucoma attack found no association with weather or atmospheric pressure. Conclusion: The majority of studies found IOP to decrease with increased atmospheric pressure and after diving. The mechanisms underlying this reduction remain incompletely understood, with potential contributors including changes in ocular blood flow, sympathetic responses, and increased oxygenation. Hyperbaric chambers may have potential in future glaucoma treatments, but more studies are required to draw reliable conclusions regarding the safety of diving for glaucoma patients.

Comparison of Peripapillary Choroidal Thickness Between Primary Open-angle Glaucoma, Normal Tension Glaucoma, and Normal Eyes: A Systematic Review and Meta-analysis.

TOPIC: To investigate differences in peripapillary choroidal thickness (PPCT) between primary open-angle glaucoma (POAG), normal tension glaucoma (NTG), and healthy eyes, additionally comparing differences between POAG and NTG eyes. CLINICAL RELEVANCE: Peripapillary choroidal thickness is a well-established OCT parameter in eyes with glaucoma and other ocular pathologies. The relationship between PPCT and glaucoma, if better understood, may facilitate the development of PPCT as a potential diagnostic and monitoring metric for glaucoma. In particular, there has yet to be a synthesis that directly compares PPCT between POAG eyes and NTG eyes. METHODS: A comprehensive literature search was performed on PubMed, EMBASE, and Cochrane Library, identifying studies from inception to December 2022. We included studies that measured PPCT using OCT in POAG, NTG, and healthy eyes. Mean difference (MD) among groups was calculated. Statistical analysis was performed using R version 4.2.0. Risk of bias of included studies was assessed using the Newcastle Ottawa Scale (NOS). RESULTS: Eighteen studies were included in this meta-analysis, with a pooled total of 935 healthy control eyes, 446 NTG eyes, and 934 POAG eyes. There was a significant reduction of PPCT in POAG eyes compared with healthy eyes [MD = -16.32; 95% confidence interval (CI) (-27.55 to -5.09)]. Reduction in PPCT was also significant in NTG eyes compared with healthy eyes [MD = -34.96; 95% CI (-49.97 to -19.95)]. NTG eyes had significantly reduced PPCT compared with POAG eyes [MD = -26.64; 95% CI (-49.00 to -4.28)]. CONCLUSIONS: Glaucomatous eyes appear to have significantly reduced PPCT compared with normal healthy eyes. In addition, PPCT in NTG eyes appear significantly thinner compared with that in POAG eyes. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Remote Perimetry in a Virtual Reality Metaverse Environment for Out-of-Hospital Functional Eye Screening Compared Against the Gold Standard Humphrey Visual Fields Perimeter: Proof-of-Concept Pilot Study.

BACKGROUND: The growing global burden of visual impairment necessitates better population eye screening for early detection of eye diseases. However, accessibility to testing is often limited and centralized at in-hospital settings. Furthermore, many eye screening programs were disrupted by the COVID-19 pandemic, presenting an urgent need for out-of-hospital solutions. OBJECTIVE: This study investigates the performance of a novel remote perimetry application designed in a virtual reality metaverse environment to enable functional testing in community-based and primary care settings. METHODS: This was a prospective observational study investigating the performance of a novel remote perimetry solution in comparison with the gold standard Humphrey visual field (HVF) perimeter. Subjects received a comprehensive ophthalmologic assessment, HVF perimetry, and remote perimetry testing. The primary outcome measure was the agreement in the classification of overall perimetry result normality by the HVF (Swedish interactive threshold algorithm-fast) and testing with the novel algorithm. Secondary outcome measures included concordance of individual testing points and perimetry topographic maps. RESULTS: We recruited 10 subjects with an average age of 59.6 (range 28-81) years. Of these, 7 (70%) were male and 3 (30%) were female. The agreement in the classification of overall perimetry results was high (9/10, 90%). The pointwise concordance in the automated classification of individual test points was 83.3% (8.2%; range 75%-100%). In addition, there was good perimetry topographic concordance with the HVF in all subjects. CONCLUSIONS: Remote perimetry in a metaverse environment had good concordance with gold standard perimetry using the HVF and could potentially avail functional eye screening in out-of-hospital settings.

Premium Intraocular Lenses in Glaucoma-A Systematic Review.

The incidence of both cataract and glaucoma is increasing globally. With increasing patient expectation and improved technology, premium intraocular lenses (IOLs), including presbyopia-correcting and toric IOLs, are being increasingly implanted today. However, concerns remain regarding the use of premium IOLs, particularly presbyopia-correcting IOLs, in eyes with glaucoma. This systematic review evaluates the use of premium IOLs in glaucoma. A comprehensive search of the MEDLINE database was performed from inception until 1 June 2023. Initial search yielded 1404 records, of which 12 were included in the final review of post-operative outcomes. Studies demonstrated high spectacle independence for distance and good patient satisfaction in glaucomatous eyes, with positive outcomes also in post-operative visual acuity, residual astigmatism, and contrast sensitivity. Considerations in patient selection include anatomical and functional factors, such as the type and severity of glaucomatous visual field defects, glaucoma subtype, presence of ocular surface disease, ocular changes after glaucoma surgery, and the reliability of disease monitoring, all of which may be affected by, or influence, the outcomes of premium IOL implantation in glaucoma patients. Regular reviews on this topic are needed in order to keep up with the rapid advancements in IOL technology and glaucoma surgical treatments.

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.

Novel surgical technique to manage iStent inject over-implantation.

PURPOSE: To describe a novel surgical technique to manage over-implantation of the iStent inject intra-operatively, utilizing only the iStent inject delivery system itself to perform both device extraction and reimplantation, without the need for additional instrumentation. METHODS: A demonstration of managing over-implantation of the iStent inject, with two case examples. RESULTS: Over-implantation of the iStent inject can be successfully managed intra-operatively to ensure ideal positioning to optimise post-operative outcomes, with the use of only the iStent inject delivery system itself for both device extraction and reimplantation. CONCLUSION: This novel technique provides a cost-effective and feasible means to intra-operatively manage over-implantation of the iStent inject.

Comparison of Efficacy of Combined Phacoemulsification and iStent Inject versus Combined Phacoemulsification and Hydrus Microstent.

Aim: This study aims to compare the efficacy and safety of combined phacoemulsification with iStent inject (Phaco-iStent) and Hydrus microstent (Phaco-Hydrus). Methods: This was a retrospective comparative study of patients who underwent Phaco-iStent from April 2019 to August 2020 and Phaco-Hydrus from August 2019 to December 2020 at a tertiary eye centre in Singapore. Sixty-nine Phaco-iStent eyes and 49 Phaco-Hydrus eyes were included in this study. Complete surgical success was defined as freedom from second glaucoma surgery, Intraocular pressure (IOP) of 18 mmHg or less, and discontinuation of all antiglaucoma medications. Results: At 12 months, both Phaco-iStent and Phaco-Hydrus groups had comparable surgical success rate (68.1% vs 51%, p=0.061), reduction in antiglaucoma medication use (-1.3 ± 0.1 vs -1.4 ± 0.10, p=0.880) and intraocular pressure reduction (-1.1 ± 0.5 mmHg vs -1.6 ± 0.9 mmHg, p=0.323). Overall intraoperative and postoperative complications rate were similar in both groups, though hyphema was more commonly seen in early postoperative period in the Phaco-Hydrus compared to the Phaco-iStent group (8% vs 0%, p=0.028), with majority of cases resolving without any need for surgical intervention. Device obstruction was also more common in the Phaco-Hydrus group compared to the Phaco-iStent group (14% vs 4.3%, p=0.04). Conclusion: Phaco-iStent and Phaco-Hydrus have similar surgical efficacy and safety profiles at 12 months.

Complications and post-operative interventions in XEN45 gel stent implantation in the treatment of open angle glaucoma-a systematic review and meta-analysis.

BACKGROUND: The XEN45 Gel Stent is a subconjunctival filtering device that has demonstrated promising efficacy. This meta-analysis quantitatively evaluates reported complications and interventions after XEN45 implantation in the treatment of open angle glaucoma (OAG). METHODS: Pilot, cohort, observational studies, and randomised controlled trials that included at least ten patients undergoing ab interno or externo XEN45 surgery, with or without phacoemulsification were deemed eligible for inclusion. A meta-analysis of proportions with random-effect models was performed using the meta routine in R version 3.2.1. Outcomes included the rate of complications and post-operative interventions. RESULTS: One hundred and fifty-two studies were identified on initial literature search and 33 were included in final analysis. Numerical hypotony was the most common post-operative complication, involving 20% of patients (95% CI: 10-31%). Post-operative gross hyphema occurred in 14% (95% CI: 7-22%) and transient intra-ocular pressure (IOP) spikes (>30 mmHg) in 13% (95% CI: 4-27%). Stent exposure occurred in 1% (95% CI: 0-2%). Stent migration occurred in 1% (95% CI: 0-3%). XEN45 revision and/or a second XEN45 implantation was performed in 5% of patients (95% CI: 3-7%). Stent relocation was performed in 3% (95% CI: 1-7%). A second glaucoma procedure was performed in 11% (95% CI: 8-15%). 26% underwent one (95% CI: 17-36%), 13% underwent two (95% CI: 5-24%) while 4% underwent three (95% CI: 2-6%) bleb needling procedures. 35% of patients (95% CI: 29-40%) required at least one needling. The average rate of needling per patient was 0.38 (95% CI: 0.20-0.59). However, there is a lack of high-quality data, with 8 of the 33 studies assessed to have a moderate to high risk of bias. CONCLUSIONS: While literature suggests that XEN45 Gel Stent implantation is safe in the treatment of OAG, the overall current level of evidence is low and further studies are needed. More than a third of patients require at least one post-operative bleb needling procedure.

A series of 777 pellet gun ocular injuries over a 4-month period in Kashmir.

Purpose: To examine the incidence, clinical findings and management of pellet gun-related ocular injuries that occurred during protests in Kashmir region. Methods: This retrospective study included records from 777 patients diagnosed with pellet gun-related ocular injuries admitted to a tertiary hospital in Srinagar, India, between July and November 2016. By reviewing the clinical records, the following data were collected: demographics, clinical information pertaining to the injury, imaging reports including computer tomography and ultrasonography B-scan, management in the emergency setting, and follow-up treatment. Results: Mean age was 22.3 ± 7.2 years and majority patients were male (97.7%). In terms of laterality, 94.3% and 5.7% of the patients sustained monocular and binocular injuries, respectively. In terms of the nature of injury, 76.3% of the eyes had open globe injury while 23.7% of the eyes had closed eye injury. Emergency surgical exploration was performed in 67.7% of closed globe injuries while emergency primary repair was done in 91.1% of open globe injuries. The vast majority of patients (98.7%) who required surgery underwent surgical intervention on the day of admission or the next day. Final best-corrected visual acuity (BCVA) after treatment was counting fingers or worse in 82.4% of the eyes. Conclusion: Pellet gun-related ocular injuries resulted in significant ocular morbidity, mostly manifesting as open globe injuries. Treatment often required surgical interventions, but despite expeditious management, visual prognosis remained poor for most of the patients.

Prospective 12-month outcomes of combined iStent inject implantation and phacoemulsification in Asian eyes with normal tension glaucoma.

BACKGROUND: Glaucoma is the leading cause of irreversible blindness. Normal tension glaucoma (NTG) is a subset of open-angle glaucoma, demonstrating glaucomatous optic nerve damage in the absence of raised intraocular pressure (IOP). NTG is more prevalent in Asian populations. While generally slow-progressing, NTG may be associated with significant central visual field loss. In recent years, minimally invasive glaucoma surgery has been added to the armamentarium of glaucoma surgery. This prospective study aims to evaluate 12-month surgical outcomes of combined iStent inject (Glaukos Corporation, Laguna Hills, CA) implantation and phacoemulsification in Asian eyes with NTG. METHODS: This is a prospective, single-centre case series of 30 eyes followed up until 12 months after surgery. Outcome measures included IOP, number of glaucoma medications, best-corrected visual acuity (BCVA) and intra and postoperative complications. RESULTS: Mean age of subjects was 73.1 ± 6.3 years. Majority were ethnic Chinese (n = 27, 90%). Baseline medicated mean IOP was 13.8 ± 2.4 mmHg and mean number of glaucoma medications was 1.3 ± 0.7. Mean Humphrey visual field mean deviation was - 13.7 ± 7.6. The mean IOP reduction at all timepoints from postoperative month (POM) 3 onwards was statistically significant (all P < 0.05), with mean reduction of 1.2 mmHg (95% CI: 0.1-2.2, P = 0.037) by POM12. There was statistically significant reduction in mean number of medications from postoperative day (POD) 1 onwards (all P < 0.05), with mean decrease of 1.0 medication (95% CI: 0.9-1.1, P < 0.001) by POM12. By POM12, 25 (83.3%) eyes were medication-free. Three (10%) eyes had stent occlusion by iris requiring laser iridoplasty. One eye had gross hyphema which resolved on conservative management before POM1. Mean BCVA improved from the baseline 0.3 ± 0.3 logMAR to 0.1 ± 0.1 logMAR postoperatively (P < 0.001). There were no major adverse or sight-threatening events. No eyes required further glaucoma surgery during the 12-month follow-up period. CONCLUSION: Asian eyes with NTG which underwent combined iStent inject implantation and phacoemulsification demonstrated a significant and sustained reduction in IOP and glaucoma medications, up to 12 months postoperatively.

Standalone XEN45 Gel Stent implantation in the treatment of open-angle glaucoma: A systematic review and meta-analysis.

The XEN45 Gel Stent (Allergan Inc., Irvine, CA) allows the drainage of aqueous into the sub-conjunctival space, through a minimally-invasive approach. This systematic review and meta-analysis evaluates its intraocular pressure (IOP)-lowering efficacy and complications in the treatment of open-angle glaucoma. Fourteen studies comprising 963 eyes were included. IOP decreased significantly (P < 0.001) across all timepoints (1 day, 1 week, 1, 3, 6, 12, 18, and 24 months) with a mean decrease of 7.44 mm Hg (95%CI:4.91-9.97) at 24 months. IOP-lowering medications decreased significantly (P < 0.001) across all timepoints (1 week, 1, 3, 6, 12, 18, 24 months) with a mean reduction of 1.67 medications (95%CI:1.28-2.06) at 24 months. Numerical hypotony occurred in 39% (95%CI:14%-67%) and stent exposure in 1% (95%CI:0%-2%) of eyes. 38% (95%CI:30%-46%) of eyes required at least one postoperative needling, with an average of 0.6 (95%CI:0.37-0.81) needlings per eye. Standalone XEN45 Gel Stent implantation is effective in lowering IOP in open-angle glaucoma. Transient numerical hypotony is the most common postoperative complication. Sight-threatening complications are rare. Postoperative needling may be required to maintain IOP-lowering outcomes; however, the overall quality of current evidence is low, with the need for more randomized controlled trials and outcomes measured with a clinically meaningful definition of success.

Anterior segment imaging in minimally invasive glaucoma surgery - A systematic review.

Minimally invasive glaucoma surgery (MIGS) has grown in popularity over the past decade. This systematic review explores the peri-operative and intraoperative application of anterior segment imaging to maximize the efficacy and safety of MIGS. A review of the PubMed, EMBASE and CINAHL databases was conducted, with inclusion criteria restricted to MIGS that had received United States Food and Drug Administration (FDA) premarket approval, FDA 510(K) premarket notification, or were listed as a class 1 device exempt from FDA approval or notification. 21 manuscripts from 21 unique studies were identified pertaining to MIGS devices including the XEN Gel Stent, Trabectome, iStent Inject, 1st-generation iStent and the Kahook Dual Blade (KDB). Anterior segment imaging modalities included anterior segment optical coherence tomography (AS-OCT), ultrasound biomicroscopy (UBM), aqueous angiography, OCT volumetric scans and in vivo confocal microscopy. Identification and evaluation of aqueous outflow pathways before and after MIGS have potential for improving patient preoperative patient selection and postoperative outcomes. Intraoperative imaging potentially provides the resolution needed for good visualization of angle anatomy and accurate evaluation of surgical endpoints in angle-based MIGS. Anterior segment imaging has been used to identify procedural complications, provide objective information on implant location in relation to surrounding anatomy, assess the post-implantation structural impact of MIGS devices and manage bleb failure and scarring. Technical difficulties in incorporating imaging modalities into the surgical microscope, variable quality of images and optical interference from ocular structures or surgical instruments are remaining barriers, which discourage the widespread clinical use of this technology.

Comparison of Surgical Outcomes of Sponge Application versus Subconjunctival Injection of Mitomycin-C during Combined Phacoemulsification and Trabeculectomy Surgery in Asian Eyes.

PURPOSE: To compare the outcomes of combined phacoemulsification-trabeculectomy surgery with intraoperative sponge-applied versus subconjunctival injection of mitomycin-C (MMC) in Asian eyes. METHODS: This was a retrospective review of 95 eyes that consecutively underwent combined phacoemulsification-trabeculectomy surgery in a tertiary eye center in Singapore from January 2013 to June 2014. Data collected included intraocular pressure (IOP), best corrected visual acuity, and number of glaucoma medications. Outcome measures included postoperative IOP and complications at various timepoints up to 12 months after surgery. RESULTS: Twenty eyes (21.1%) received 0.2 mg/ml subconjunctival MMC injection ("Group 1") and 75 (78.9%) received 0.4 mg/ml sponge-applied MMC ("Group 2"). There was no difference between groups in demographics, IOP, and number of glaucoma medications preoperatively. There was a reduction in IOP at postoperative month (POM) 1, 6, and 12 in both the groups (POM12: Group 1, -2.8 ± 5.36 mmHg, P < 0.001; Group 2, -5.8 ± 6.29 mmHg, P = 0.054). At POM1, Group 2 showed a trend toward greater IOP reduction (-5.89 ± 7.67 mmHg vs. -1.55 ± 5.68 mmHg, P = 0.061). However, at both POM6 and POM12, there was no statistically significant difference in IOP reduction between the two groups. At POM12, complete success, defined as achieving an IOP of between 6 and 15 mmHg without the use of antiglaucoma medications, was achieved in 11 (55%) eyes in Group 1 and 48 (64%) in Group 2 (P = 0.9). There was a lower rate of postoperative hypotony in the Group 1 (0%) compared to Group 2 (8%) (P = 0.34). CONCLUSION: Combined phacoemulsification-trabeculectomy with subconjunctival MMC injection has comparable outcomes to that with sponge-applied MMC, with a similar reduction in IOP at 1, 6, and 12 months postoperatively and a lower postoperative complication rate.

Standalone XEN45 Gel Stent implantation versus combined XEN45-phacoemulsification in the treatment of open angle glaucoma-a systematic review and meta-analysis.

PURPOSE: The XEN45 Gel Stent is currently the only FDA-approved sub-conjunctival minimally invasive glaucoma surgery (MIGS) procedure. It has been used worldwide either as a standalone implantation procedure or in combination with phacoemulsification surgery. Concomitant phacoemulsification is understood to influence outcomes of traditional subconjunctival filtering surgery. However, the comparative efficacy between standalone XEN45 Gel Sent implantation ("Standalone XEN45") and combined XEN-phacoemulsification surgery ("XEN45-Phaco") remains unclear. This study aims to appraise current literature to compare the efficacy of Standalone XEN45 and XEN45-Phaco in open-angle glaucoma. METHODS: A comprehensive search of PubMed, CINAHL, CENTRAL databases was performed with the terms "Xen surgery" followed by selective vetting. Pilot, cohort, observational studies and randomised controlled trials that included at least 10 patients undergoing either Standalone XEN45 or XEN45-Phaco surgeries for the treatment of open-angle glaucoma were deemed eligible for inclusion after independent assessment by 2 authors. The search workflow was reported according to the PRISMA guidelines. Data was pooled using random-effects model. A meta-analysis of continuous outcome and proportions was performed using the meta routine in R v3.2.1. RESULTS: Ten studies were included. There was a statistically significant difference in IOP reduction favouring Standalone XEN45 at post-operative day 1, week 1, months 1, 3 and 6. There was a statistically significant difference in decrease in IOP-lowering medications favouring Standalone XEN45 at post-operative week 1 and month 1. CONCLUSION: Standalone XEN45 has superior IOP-lowering outcomes compared to XEN45-Phaco in the early post-operative period, up to 6 months after surgery.

Association of SNTB1 with High Myopia.

PURPOSE: To investigate the associations of Single Nucleotide Polymorphisms (SNPs) in the SNTB1 gene with high myopia in a Han Chinese population. MATERIALS AND METHODS: Based on previous studies, four SNPs from the SNTB1 gene were chosen for genotyping. This is a case-control genetic association study comprising 193 high myopia participants and 135 normal emmetropic controls from a Han Chinese population. Allelic frequencies of the SNPs and haplotypes were compared to assess the associations of the SNPs with high myopia and axial length (AL). RESULTS: The SNPs rs7839488 (effect allele: A; OR = 0.685), rs4395927 (effect allele: T; OR = 0.692), and rs6469937 (effect allele: A; OR = 0.683) displayed significant associations with high myopia initially (P = .044, 0.049, and 0.035, respectively), but did not withstand permutation testing (all Ppermutation>0.05). rs6469937 displayed associations with high myopia in the dominant model (AG+AA: OR = 0.609) against GG (reference). rs6469937 was also associated with AL in the dominant model (AG+AA: Beta = -0.58) against GG (reference). The haplotype analysis demonstrated ATGA as the protective haplotype against high myopia, which remained statistically significant in permutation testing (Ppermutation = 0.045). CONCLUSIONS: Our findings are suggestive that SNTB1 is associated with high myopia in a Han Chinese population.

Correlation of myopia severity with visual performance.

PURPOSE: To describe visual performance in high myopia. METHODS: In this cross-sectional study, 148 emmetropes [spherical equivalent (SE) - 0.50 to + 1.00 D] and 564 high myopes [SE ≤ - 6.00 D] were categorised into three groups (Group 1: SE - 6.00 to > - 8.00 D; Group 2: SE - 8.00 to > - 10.00 D; and Group 3: SE ≤ - 10.00 D). Multivariate regression analyses adjusting for age and ethnicity examined the relationship between corrected distance visual acuity (CDVA) [photopic, mesopic and super vision test-night vision goggles (SVT-NVG)] and contrast sensitivity (CS)] (mesopic and SVT-NVG) with SE and axial length (AL). RESULTS: Mean age of subjects was 21.07 ± 1.17 years, and majority were Chinese (91.9%). Mean SE was 0.10 ± 0.23 D (emmetropes) and - 8.76 ± 2.04 D (high myopes), p < 0.001. Higher degrees of myopia were associated with reduced CDVA and CS, and increased AL (all p < 0.001). Among high myopes, Group 1 had the highest proportion of subjects with good CDVA (photopic ≤ 0.00 LogMAR, mesopic ≤ 0.00 LogMAR and NVG ≤ 0.10 LogMAR) and CS (mesopic ≥ 0.75 LogCS and NVG ≥ 0.35 LogCS) compared with Groups 2 and 3 (all p < 0.001). Among high myopes with good VA (photopic ≤ 0.00 LogMAR, mesopic ≤ 0.00 LogMAR and NVG ≤ 0.10 LogMAR), Group 1 also had the highest proportion of subjects who achieved mesopic ≥ 0.75 LogCS and NVG ≥ 0.35 LogCS (both p < 0.001). Multivariate analyses demonstrated that reduced VA and CS were associated with decreased SE and increased AL (all p < 0.001). CONCLUSIONS: High myopia is associated with reduced VA and reduced CS.