Glaucoma

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Sii S, Barton K, Pasquale LR, Yamamoto T, King AJ, Azuara-Blanco A. Reporting Harm in Glaucoma Surgical Trials: Systematic Review and a Consensus-Derived New Classification System. Am J Ophthalmol 2018;194:153-162.Abstract
PURPOSE: To evaluate the standards of harm reporting for glaucoma surgical trials and to develop a classification system for reporting surgical complication severity. DESIGN: Systematic review and Delphi consensus method. METHODS: Systematic review of glaucoma surgical trials published from January 2010 until July 2017 with a quality assessment against the CONSORT checklist for harm. A Delphi method was employed to generate consensus grading (interquartile range ≤ 2) among international glaucoma experts (n = 43) on severity of glaucoma surgical complications, and specifically for trabeculectomy and aqueous shunt complications, from 1 (no clinical significance) to 10 (most severe complication). RESULTS: Forty-seven studies were eligible. The items of the CONSORT checklist for harm that were most frequently missing were use of a validated instrument to report severity (0%), withdrawals due to harm, and subgroup analyses, both reported in 3 publications (6.4%). Most glaucoma experts participating in the Delphi process (80%) completed the second round, and consensus was achieved for all but 1 complication. The least severe complications (graded 2) were "transient loss of vision," "early low intraocular pressure," "choroidal detachment anterior to equator," "small layered hyphema < 1 mm," and "increased lens opacity not clinically significant." The most severe complications (graded 10) were "endophthalmitis" and "permanent severe loss of vision (hand movements or worse)." CONCLUSIONS: Glaucoma surgical randomized controlled trials report frequency of complications, but their severity is rarely reported. The quality of harm reporting is poor. We propose the use of a newly developed system of classification for assessing the severity of surgical complications based on consensus.
Silva RNE, Shen LQ, Chiou CA, Shanbhag SS, Paschalis EI, Pasquale LR, Colby KA, Dohlman CH, Chodosh J, Alves MR. Glaucoma Management in Patients with Aniridia and Boston Type 1 Keratoprosthesis. Am J Ophthalmol 2019;Abstract
PURPOSE: To assess outcomes and glaucoma management in eyes with aniridia following Boston type 1 Keratoprosthesis (KPro) implantation. DESIGN: Retrospective, interventional comparative case series. METHODS: POPULATION: Patients with aniridia and patients with other preoperative diagnoses (excluding Stevens-Johnson syndrome, mucous membrane pemphigoid, and congenital disorders) who underwent KPro implantation at Massachusetts Eye and Ear with at least 2 years of follow-up. One eye per patient was selected based on the longer follow-up time. MAIN OUTCOME: Intermediate and long-term outcomes related to glaucoma. RESULTS: The aniridia (n=22) and comparison (n=61) groups had similar preoperative visual acuity (VA, mean ± standard deviation, 1.86±0.52 LogMAR, p=0.33) and follow-up time (65.6±26.3 months, p=0.25). Prior to KPro implantation, eyes with aniridia had more glaucoma (76.2%) and glaucoma surgery (57.1%) than comparison eyes (51.8%, p=0.053; 23.2%, p=0.005, respectively). More Ahmed valves were co-implanted with KPro in aniridia (47.6%) versus comparison eyes (17.9%, p=0.008). At final follow-up, more aniridia eyes had glaucoma (90.5%) than comparison eyes (64.3%, p=0.02), but the two groups had similar percentages of eyes with cup-to-disc ratio (CDR) >0.8 (23.8% vs. 30.4%, p=0.57) or CDR progression of ≥0.2 (42.9% vs. 44.6%, p=0.89, respectively). None of the eyes with prophylactic tube implantation developed glaucoma. Eyes with and without aniridia did not differ in post-KPro VA improvement (72.7%, 72.1%, p=0.96), and final VA (1.28±0.79 LogMAR, 1.23±0.98 LogMAR, p=0.51). CONCLUSION: Despite a higher glaucoma prevalence, eyes with aniridia achieved similar VA as comparison eyes with more than 5 years of mean follow-up time. Boston KPro offers satisfactory visual rehabilitation in aniridia when glaucoma is managed aggressively.
Silva RNE, Taniguchi EV, Cruzat A, Paschalis EI, Pasquale LR, Colby KA, Dohlman CH, Chodosh J, Shen LQ. Angle Anatomy and Glaucoma in Patients With Boston Keratoprosthesis. Cornea 2020;39(6):713-719.Abstract
PURPOSE: To quantitatively analyze the angle anatomy in eyes with a Boston type 1 keratoprosthesis (KPro) using anterior segment optical coherence tomography (AS-OCT) and to assess the diagnostic ability of AS-OCT in KPro-associated glaucoma. METHODS: AS-OCT (RTVue) images from KPro eyes with and without glaucoma were reviewed. The angle opening distance at 500 μm from the scleral spur (AOD500), trabecular-iris angle at 500 μm from the scleral spur (TIA500), and trabecular-iris surface area at 500 μm from the scleral spur (TISA500) were measured by 2 observers masked to the diagnosis. The measurements for each visible quadrant were compared between KPro eyes with and without glaucoma. RESULTS: Twenty-two eyes with glaucoma and 17 eyes without glaucoma from 39 patients with KPro were included. Of the 4 quadrants imaged, the temporal angle was the most visible (79.5%) and angle measurements of the temporal quadrant were the only ones that differentiated the 2 groups: the mean AOD500, TIA500, and TISA500 were significantly lower in KPro eyes with glaucoma than without glaucoma (388.2 ± 234.4 μm vs. 624.5 ± 310.5 μm, P = 0.02; 26.1 ± 14.0 degrees vs. 39.1 ± 17.1 degrees, P = 0.03; and 0.15 ± 0.09 mm vs. 0.23 ± 0.12 mm, P = 0.03; respectively). The highest area under the receiver operating characteristic curve for detecting glaucoma was 0.75 for temporal TIA500 (95% confidence interval 0.57-0.94, P = 0.02) with 50% specificity at 80% of sensitivity and a cutoff value of 37 degrees. CONCLUSIONS: The temporal angle was the most visible on AS-OCT in eyes with a KPro. Significant narrowing of the temporal angle detected on AS-OCT was associated with glaucoma in these eyes.
Silva RNE, Chiou CA, Wang M, Wang H, Shoji MK, Chou JC, D'Souza EE, Greenstein SH, Brauner SC, Alves MR, Pasquale LR, Shen LQ. Microvasculature of the Optic Nerve Head and Peripapillary Region in Patients With Primary Open-Angle Glaucoma. J Glaucoma 2019;28(4):281-288.Abstract
PURPOSE: To assess optic nerve head (ONH) and peripapillary microvasculature in primary open-angle glaucoma (POAG) of mild to moderate severity using swept-source optical coherence tomography angiography (OCTA). MATERIALS AND METHODS: In a cross-sectional study, swept-source OCTA images were analyzed for 1 eye from each of 30 POAG patients with glaucomatous Humphrey visual field loss and 16 controls. The anatomic boundary of ONH was manually delineated based on Bruch's membrane opening and large vessels were removed from en face angiography images to measure vessel density (VD) and the integrated OCTA by ratio analysis signal (IOS), suggestive of flow, in the ONH and peripapillary region. POAG subgroup analysis was performed based on a history of disc hemorrhage (DH) matched by visual field mean deviation (MD). RESULTS: POAG (mean MD±SD, -3.3±3.0 dB) and control groups had similar demographic characteristics and intraocular pressure on the day of imaging. Groups did not differ in superficial ONH VD or flow indicated by IOS (P≥0.28). POAG eyes showed significantly lower VD (39.4%±4.0%) and flow (38.8%±5.6%) in deep ONH, peripapillary VD (37.9%±2.9%) and flow (43.6%±4.0%) compared with control eyes (44.1%±5.1%, 44.7%±6.9%, 40.7%±1.7%, 47.8%±2.5%, respectively; P≤0.007 for all). In the subgroup analysis, POAG eyes with (n=14) and without DH (n=16) had similar measured OCTA parameters (P>0.99 for all). CONCLUSIONS: The image processing methodology based on the anatomic boundary of ONH demonstrated compromised microvasculature in the deep ONH and peripapillary region in eyes with mild to moderate POAG, regardless of the history of DH.
Silva RNE, Chiou CA, Wang M, Devlin J, Li D, Lovelace S, Wang H, Greenstein SH, Brauner SC, Shen LQ. Quantification of the Peripapillary Microvasculature in Eyes with Glaucomatous Paracentral Visual Field Loss. Ophthalmol Glaucoma 2021;4(3):286-294.Abstract
PURPOSE: To quantify abnormalities in the peripapillary microvasculature in eyes with primary open-angle glaucoma (POAG) and paracentral visual field (VF) loss. DESIGN: Prospective, cross-sectional study. PARTICIPANTS: Thirty-three POAG patients, including 15 with paracentral VF loss and 18 with peripheral VF loss, and 31 control participants underwent swept-source OCT angiography (OCTA) of the peripapillary region. METHODS: The POAG groups were matched by VF mean deviation (MD). The peripapillary microvasculature from the internal limiting membrane to the retinal nerve fiber layer (RNFL) interface was quantified within a 0.70-mm annulus around Bruch's membrane opening after removal of large vessels. Both vessel density (VD) and the integrated OCTA by ratio analysis signal (IOS) suggestive of flow were measured. Regional VD and IOS were measured from the affected hemisphere corresponding to the VF hemifield of more severe loss, which was used to calculate the paracentral total deviation (PaTD), or total deviation within the central 10°. One eye per participant was included. MAIN OUTCOME MEASURES: Difference in peripapillary OCTA measurements between paracentral and peripheral VF loss groups and correlation of peripapillary VD and IOS with PaTD. RESULTS: The POAG groups had matched VF MD (-3.1 ± 2.5 dB paracentral vs. -2.3 ± 2.0 dB peripheral; P = 0.31), did not differ in average RNFL thickness (71.1 ± 14.7 μm vs. 78.1 ± 15.0 μm; P = 0.55), but differed in age (59.2 ± 9.6 years paracentral vs. 67.4 ± 6.6 years peripheral; P = 0.02). Compared with control participants, both paracentral and peripheral VF loss groups showed reduced VD (P < 0.001 and P = 0.009, respectively) and IOS (P < 0.001 and P = 0.01, respectively) in the affected hemisphere. Compared with POAG eyes with peripheral VF loss, the paracentral group showed reduced peripapillary VD (38.0 ± 2.0%, 35.0 ± 2.2%, respectively; P = 0.001) and IOS (44.3 ± 3.1%, 40.4 ± 4.0%, respectively; P = 0.02) in the affected hemisphere. Among all POAG eyes, peripapillary VD and IOS of the affected hemisphere correlated significantly with functional measurement of paracentral loss (PaTD, r = 0.40, P = 0.02; r = 0.45, P = 0.008; respectively). These correlations remained significant after adjusting for age (r = 0.41, P = 0.02; r = 0.47, P = 0.01; respectively). CONCLUSIONS: Regional peripapillary microvasculature showed decreased VD and flow in POAG with paracentral loss, supporting its importance in this glaucoma subtype.
Simavli H, Poon LY-C, Que CJ, Liu Y, Akduman M, Tsikata E, de Boer JF, Chen TC. Diagnostic Capability of Peripapillary Retinal Volume Measurements in Glaucoma. J Glaucoma 2017;26(6):592-601.Abstract
PURPOSE: To determine the diagnostic capability of spectral domain optical coherence tomography peripapillary retinal volume (RV) measurements. MATERIALS AND METHODS: A total of 156 patients, 89 primary open-angle glaucoma and 67 normal subjects, were recruited. Spectral domain optical coherence tomography peripapillary RV was calculated for 4 quadrants using 3 annuli of varying scan circle diameters: outer circumpapillary annuli of circular grids 1, 2, and 3 (OCA1, OCA2, OCA3). Area under the receiver operating characteristic curves and pairwise comparisons of receiver operating characteristic (ROC) curves were performed to determine which quadrants were best for diagnosing primary open-angle glaucoma. The pairwise comparisons of the best ROC curves for RV and retinal nerve fiber layer (RNFL) were performed. The artifact rates were analyzed. RESULTS: Pairwise comparisons showed that the smaller annuli OCA1 and OCA2 had better diagnostic performance than the largest annulus OCA3 (P<0.05 for all quadrants). OCA1 and OCA2 had similar diagnostic performance, except for the inferior quadrant which was better for OCA1 (P=0.0033). The pairwise comparisons of the best ROC curves for RV and RNFL were not statistically significant. RV measurements had lower rates of artifacts at 7.4% while RNFL measurements had higher rates at 42.9%. CONCLUSIONS: Peripapillary RV measurements have excellent ability for diagnosing not only glaucoma patients but also a subset of early glaucoma patients. The inferior quadrant of peripapillary annulus OCA1 demonstrated the best diagnostic capability for both glaucoma and early glaucoma. The diagnostic ability of RV is comparable with that of RNFL parameters in glaucoma but with lower artifact rates.
Simavli H, Que CJ, Akduman M, Rizzo JL, Tsikata E, de Boer JF, Chen TC. Diagnostic capability of peripapillary retinal thickness in glaucoma using 3D volume scans. Am J Ophthalmol 2015;159(3):545-56.e2.Abstract

PURPOSE: To determine the diagnostic capability of spectral-domain optical coherence tomography (SD OCT) peripapillary retinal thickness (RT) measurements from 3-dimensional (3D) volume scans for primary open-angle glaucoma (POAG). DESIGN: Cross-sectional study. METHODS: setting: Institutional. study population: 156 patients (89 POAG and 67 normal subjects). observation procedures: One eye of each subject was included. SD OCT peripapillary RT values from 3D volume scans were calculated for 4 quadrants of 3 different sized annuli. Peripapillary retinal nerve fiber layer (RNFL) thickness values were also determined. main outcome measures: Area under the receiver operating characteristic curve (AUROC) values, sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios. RESULTS: The top 5 RT AUROCs for all glaucoma patients and for a subset of early glaucoma patients were for the inferior quadrant of outer circumpapillary annulus of circular grid (OCA) 1 (0.959, 0.939), inferior quadrant of OCA2 (0.945, 0.921), superior quadrant of OCA1 (0.890, 0.811), inferior quadrant of OCA3 (0.887, 0.854), and superior quadrant of OCA2 (0.879, 0.807). Smaller RT annuli OCA1 and OCA2 consistently showed better diagnostic performance than the larger RT annulus OCA3. For both RNFL and RT measurements, best AUROC values were found for inferior RT OCA1 and OCA2, followed by inferior and overall RNFL thickness. CONCLUSION: Peripapillary RT measurements from 3D volume scans showed excellent diagnostic performance for detecting both glaucoma and early glaucoma patients. Peripapillary RT values have the same or better diagnostic capability compared to peripapillary RNFL thickness measurements, while also having fewer algorithm errors.

Simcoe MJ, Shah A, Fan BJ, Choquet H, Weisschuh N, Waseem NH, Jiang C, Melles RB, Ritch R, Mahroo OA, Wissinger B, Jorgenson E, Wiggs JL, Garway-Heath DF, Hysi PG, Hammond CJ. Genome-Wide Association Study Identifies Two Common Loci Associated with Pigment Dispersion Syndrome/Pigmentary Glaucoma and Implicates Myopia in its Development. Ophthalmology 2022;129(6):626-636.Abstract
PURPOSE: To identify genetic variants associated with pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG) in unrelated patients and to further understand the genetic and potentially causal relationships between PDS and associated risk factors. DESIGN: A 2-stage genome-wide association meta-analysis with replication and subsequent in silico analyses including Mendelian randomization. PARTICIPANTS: A total of 574 cases with PG or PDS and 52 627 controls of European descent. METHODS: Genome-wide association analyses were performed in 4 cohorts and meta-analyzed in 3 stages: (1) a discovery meta-analysis was performed in 3 cohorts, (2) replication was performed in the fourth cohort, and (3) all 4 cohorts were meta-analyzed to increase statistical power. Two-sample Mendelian randomization was used to determine whether refractive error and intraocular pressure exert causal effects over PDS. MAIN OUTCOME MEASURES: The association of genetic variants with PDS and whether myopia exerts causal effects over PDS. RESULTS: Significant association was present at 2 novel loci for PDS/PG. These loci and follow-up analyses implicate the genes gamma secretase activator protein (GSAP) (lead single nucleotide polymorphism [SNP]: rs9641220, P = 6.0×10-10) and glutamate metabotropic receptor 5 (GRM5)/TYR (lead SNP: rs661177, P = 3.9×10-9) as important factors in disease risk. Mendelian randomization showed significant evidence that negative refractive error (myopia) exerts a direct causal effect over PDS (P = 8.86×10-7). CONCLUSIONS: Common SNPs relating to the GSAP and GRM5/TYR genes are associated risk factors for the development of PDS and PG. Although myopia is a known risk factor, this study uses genetic data to demonstrate that myopia is, in part, a cause of PDS and PG.
Singh R, Rauscher FG, Li Y, Eslami M, Kazeminasab S, Zebardast N, Wang M, Elze T. Normative Percentiles of Retinal Nerve Fiber Layer Thickness and Glaucomatous Visual Field Loss. Transl Vis Sci Technol 2023;12(10):13.Abstract
PURPOSE: Circumpapillary retinal nerve fiber layer thickness (RNFLT) measurement aids in the clinical diagnosis of glaucoma. Spectral domain optical coherence tomography (SD-OCT) machines measure RNFLT and provide normative color-coded plots. In this retrospective study, we investigate whether normative percentiles of RNFLT (pRNFLT) from Spectralis SD-OCT improve prediction of glaucomatous visual field loss over raw RNFLT. METHODS: A longitudinal database containing OCT scans and visual fields from Massachusetts Eye & Ear glaucoma clinic patients was generated. Reliable OCT-visual field pairs were selected. Spectralis OCT normative distributions were extracted from machine printouts. Supervised machine learning models compared predictive performance between pRNFLT and raw RNFLT inputs. Regional structure-function associations were assessed with univariate regression to predict mean deviation (MD). Multivariable classification predicted MD, pattern standard deviation, MD change per year, and glaucoma hemifield test. RESULTS: There were 3016 OCT-visual field pairs that met the reliability criteria. Spectralis norms were found to be independent of age, sex, and ocular magnification. Regional analysis showed significant decrease in R2 from pRNFLT models compared to raw RNFLT models in inferotemporal sectors, across multiple regressors. In multivariable classification, there were no significant improvements in area under the curve of receiver operating characteristic curve (ROC-AUC) score with pRNFLT models compared to raw RNFLT models. CONCLUSIONS: Our results challenge the assumption that normative percentiles from OCT machines improve prediction of glaucomatous visual field loss. Raw RNFLT alone shows strong prediction, with no models presenting improvement by the manufacturer norms. This may result from insufficient patient stratification in tested norms. TRANSLATIONAL RELEVANCE: Understanding correlation of normative databases to visual function may improve clinical interpretation of OCT data.
Singh RK, Smith S, Fingert J, Gordon M, Kass M, Scheetz T, Segrè AV, Wiggs J, Elze T, Zebardast N. Machine Learning-Derived Baseline Visual Field Patterns Predict Future Glaucoma Onset in the Ocular Hypertension Treatment Study. Invest Ophthalmol Vis Sci 2024;65(2):35.Abstract
PURPOSE: The Ocular Hypertension Treatment Study (OHTS) identified risk factors for primary open-angle glaucoma (POAG) in patients with ocular hypertension, including pattern standard deviation (PSD). Archetypal analysis, an unsupervised machine learning method, may offer a more interpretable approach to risk stratification by identifying patterns in baseline visual fields (VFs). METHODS: There were 3272 eyes available in the OHTS. Archetypal analysis was applied using 24-2 baseline VFs, and model selection was performed with cross-validation. Decomposition coefficients for archetypes (ATs) were calculated. A penalized Cox proportional hazards model was implemented to select discriminative ATs. The AT model was compared to the OHTS model. Associations were identified between ATs with both POAG onset and VF progression, defined by mean deviation change per year. RESULTS: We selected 8494 baseline VFs. Optimal AT count was 19. The highest prevalence ATs were AT9, AT11, and AT7. The AT-based prediction model had a C-index of 0.75 for POAG onset. Multivariable models demonstrated that a one-interquartile range increase in the AT5 (hazard ratio [HR] = 1.14; 95% confidence interval [CI], 1.04-1.25), AT8 (HR = 1.22; 95% CI, 1.09-1.37), AT15 (HR = 1.26; 95% CI, 1.12-1.41), and AT17 (HR = 1.17; 95% CI, 1.03-1.31) coefficients conferred increased risk of POAG onset. AT5, AT10, and AT14 were significantly associated with rapid VF progression. In a subgroup analysis by high-risk ATs (>95th percentile or <75th percentile coefficients), PSD lost significance as a predictor of POAG in the low-risk group. CONCLUSIONS: Baseline VFs, prior to detectable glaucomatous damage, contain occult patterns representing early changes that may increase the risk of POAG onset and VF progression in patients with ocular hypertension. The relationship between PSD and POAG is modified by the presence of high-risk patterns at baseline. An AT-based prediction model for POAG may provide more interpretable glaucoma-specific information in a clinical setting.
Singh RB, Ichhpujani P, Thakur S, Jindal S. Promising therapeutic drug delivery systems for glaucoma: a comprehensive review. Ther Adv Ophthalmol 2020;12:2515841420905740.Abstract
The delivery of ophthalmic drugs is challenging despite easy accessibility via the ocular surface. Topical instillation of eye drops is a relatively easy and most commonly used as a conduit for drug delivery for treating a myriad of ocular morbidities, particularly involving the anterior segment, and has an additional benefit of avoiding the first-pass metabolism while passing through the systemic circulation. The primary challenges of drug administration through traditional methods include-inadequate patient education for proper drug instillation technique, compliance, adherence, and persistence. Various dynamic (choroidal and conjunctival blood flow, lymphatic clearance, and tear dilution) and static (namely, different layers of cornea, sclera, and retina including blood aqueous and blood-retinal barriers) ocular barriers limit drug delivery to the target ocular tissues. The maintenance of the therapeutic drug levels on the ocular surface for a prolonged duration is an added challenge, thus preventing persistent delivery for longer durations. These factors result in inadequate management, leading to poor prognosis in vision loss in as many as 27% of the patients diagnosed with glaucoma. We have reviewed the research and advancements in the development of novel and well-tolerated drug delivery systems with the common goal of overcoming the factors limiting adequate drug delivery to the target tissues in glaucomatous patients with traditional techniques. In the recent past, multiple research groups have successfully designed noninvasive, sustained drug delivery systems, promoting the efficacy as well as the feasibility of delivering topical drugs to the anterior segment.
Sit AJ, Chen TC, Takusagawa HL, Rosdahl JA, Hoguet A, Chopra V, Richter GM, Ou Y, Kim SJ, WuDunn D. Corneal Hysteresis for the Diagnosis of Glaucoma and Assessment of Progression Risk: A Report by the American Academy of Ophthalmology. Ophthalmology 2023;130(4):433-442.Abstract
PURPOSE: To review the current published literature on the utility of corneal hysteresis (CH) to assist the clinician in the diagnosis of glaucoma or in the assessment of risk for disease progression in existing glaucoma patients. METHODS: Searches of the peer-reviewed literature in the PubMed database were performed through July 2022. The abstracts of 423 identified articles were examined to exclude reviews and non-English articles. After inclusion and exclusion criteria were applied, 19 articles were selected, and the panel methodologist rated them for level of evidence. Eight articles were rated level I, and 5 articles were rated level II. The 6 articles rated level III were excluded. RESULTS: Corneal hysteresis is lower in patients with primary open-angle glaucoma, primary angle-closure glaucoma, pseudoexfoliative glaucoma, and pseudoexfoliation syndrome compared with normal subjects. Interpretation of low CH in patients with high intraocular pressure (IOP) or on topical hypotensive medications is complicated by the influence of these parameters on CH measurements. However, CH is also lower in treatment-naïve, normal-tension glaucoma patients compared with normal subjects who have a similar IOP. In addition, lower CH is associated with an increased risk of progression of glaucoma based on visual fields or structural markers in open-angle glaucoma patients, including those with apparently well-controlled IOP. CONCLUSIONS: Corneal hysteresis is lower in glaucoma patients compared with normal subjects, and lower CH is associated with an increased risk of disease progression. However, a causal relationship remains to be demonstrated. Nevertheless, measurement of CH complements current structural and functional assessments in determining disease risk in glaucoma suspects and patients. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.
Smits DJ, Elze T, Wang H, Pasquale LR. Machine Learning in the Detection of the Glaucomatous Disc and Visual Field. Semin Ophthalmol 2019;:1-11.Abstract
Glaucoma is the leading cause of irreversible blindness worldwide. Early detection is of utmost importance as there is abundant evidence that early treatment prevents disease progression, preserves vision, and improves patients' long-term quality of life. The structure and function thresholds that alert to the diagnosis of glaucoma can be obtained entirely via digital means, and as such, screening is well suited to benefit from artificial intelligence and specifically machine learning. This paper reviews the concepts and current literature on the use of machine learning for detection of the glaucomatous disc and visual field.
Soh ZD, Tan M, Nongpiur ME, Xu BY, Friedman D, Zhang X, Leung C, Liu Y, Koh V, Aung T, Cheng C-Y. Assessment of angle closure disease in the age of artificial intelligence: A review. Prog Retin Eye Res 2024;98:101227.Abstract
Primary angle closure glaucoma is a visually debilitating disease that is under-detected worldwide. Many of the challenges in managing primary angle closure disease (PACD) are related to the lack of convenient and precise tools for clinic-based disease assessment and monitoring. Artificial intelligence (AI)- assisted tools to detect and assess PACD have proliferated in recent years with encouraging results. Machine learning (ML) algorithms that utilize clinical data have been developed to categorize angle closure eyes by disease mechanism. Other ML algorithms that utilize image data have demonstrated good performance in detecting angle closure. Nonetheless, deep learning (DL) algorithms trained directly on image data generally outperformed traditional ML algorithms in detecting PACD, were able to accurately differentiate between angle status (open, narrow, closed), and automated the measurement of quantitative parameters. However, more work is required to expand the capabilities of these AI algorithms and for deployment into real-world practice settings. This includes the need for real-world evaluation, establishing the use case for different algorithms, and evaluating the feasibility of deployment while considering other clinical, economic, social, and policy-related factors.
Soh Z, Yu M, Betzler BK, Majithia S, Thakur S, Tham YC, Wong TY, Aung T, Friedman DS, Cheng C-Y. The Global Extent of Undetected Glaucoma in Adults: A Systematic Review and Meta-analysis. Ophthalmology 2021;128(10):1393-1404.Abstract
TOPIC: Glaucoma is the leading cause of irreversible blindness, despite having good prognosis with early treatment. We evaluated the global extent of undetected glaucoma and the factors associated with it in this systematic review and meta-analysis. CLINICAL RELEVANCE: Undetected glaucoma increases the risk of vision impairment, which leads to detrimental effects on the quality-of-life and socioeconomic well-being of those affected. Detailed information on the extent and factors associated with undetected glaucoma aid in the development of public health interventions. METHODS: We conducted a systematic review and meta-analysis of population-based studies published between January 1, 1990, and June 1, 2020. Article search was conducted in online databases (PubMED, Web-of-Science), grey literatures (OpenGrey), and nongovernment organization reports. Our outcome measure was the proportion of glaucoma cases that were undetected previously. Manifest glaucoma included any form of glaucoma reported in the original studies and may include primary open-angle glaucoma (POAG), primary angle-closure-glaucoma, secondary glaucoma, or a combination thereof. Undetected glaucoma was defined as glaucoma cases that were undetected prior to diagnosis in the respective study. Random-effect meta-analysis was used to estimate the pooled proportion of undetected glaucoma. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the Meta-analysis of Observational Studies in Epidemiology guidelines in our study. RESULTS: We identified 61 articles from 55 population-based studies (n = 189 359 participants; n = 6949 manifest glaucoma). Globally, more than half of all glaucoma cases were undetected previously on average in each geographical region. Africa (odds ratio [OR], 12.70; 95% confidence interval [CI], 4.91-32.86) and Asia (OR, 3.41; 95% CI, 1.63-7.16) showed higher odds of undetected glaucoma as compared with Europe. Countries with low Human Development Index (HDI; <0.55) showed a higher proportion of undetected manifest glaucoma as compared with countries of medium to very high HDI (≥0.55; all P < 0.001). In 2020, 43.78 million POAG cases were projected to be undetected, of which 76.7% were in Africa and Asia. DISCUSSION: Undetected glaucoma is highly prevalent across diverse communities worldwide and more common in Africa and Asia. Strategies to improve detection are needed to prevent excess visual disability and blindness resulting from glaucoma.
Song BJ, Aiello LP, Pasquale LR. Presence and Risk Factors for Glaucoma in Patients with Diabetes. Curr Diab Rep 2016;16(12):124.Abstract

Diabetes mellitus represents a growing international public health issue with a near quadrupling in its worldwide prevalence since 1980. Though it has many known microvascular complications, vision loss from diabetic retinopathy is one of the most devastating for affected individuals. In addition, there is increasing evidence to suggest that diabetic patients have a greater risk for glaucoma as well. Though the pathophysiology of glaucoma is not completely understood, both diabetes and glaucoma appear to share some common risk factors and pathophysiologic similarities with studies also reporting that the presence of diabetes and elevated fasting glucose levels are associated with elevated intraocular pressure-the primary risk factor for glaucomatous optic neuropathy. While no study has completely addressed the possibility of detection bias, most recent epidemiologic evidence suggests that diabetic populations are likely enriched with glaucoma patients. As the association between diabetes and glaucoma becomes better defined, routine evaluation for glaucoma in diabetic patients, particularly in the telemedicine setting, may become a reasonable consideration to reduce the risk of vision loss in these patients.

Song BJ, Ramanathan M, Morales E, Law SK, Giaconi JAA, Coleman AL, Caprioli J. Trabeculectomy and Combined Phacoemulsification-Trabeculectomy: Outcomes and Risk Factors for Failure in Primary Angle Closure Glaucoma. J Glaucoma 2016;25(9):763-9.Abstract

PURPOSE: To evaluate tonometric outcomes of patients with primary angle closure glaucoma (PACG) who have undergone trabeculectomy with mitomycin C (MMC) with and without concurrent phacoemulsification and to identify risk factors for postoperative failure. PATIENTS AND METHODS: Retrospective cohort study of 44 eyes of 33 phakic patients who underwent trabeculectomy with MMC with or without combined phacoemulsification for PACG. The primary endpoint was qualified tonometric success at 12 months according to predefined criteria. LogMAR visual acuity, number of glaucoma medications, and postoperative complications were also evaluated. Cox proportional hazard regression analysis was performed to identify potential risk factors for trabeculectomy failure. RESULTS: Mean intraocular pressure (IOP) decreased from 21.3±7.9 to 12.2±3.9 mm Hg at 12 months (P<0.001) in all patients. A significant reduction in mean number of glaucoma medications (P<0.001) was also seen. There was no change in logMAR visual acuity (P=0.39) after 12 months. There were no significant intergroup differences in mean IOP (P=0.42), number of glaucoma medications (P=0.85), or logMAR visual acuity (P=0.42) between the trabeculectomy versus combined surgery groups after 12 months. Increased age, greater baseline IOP, limbus-based conjunctival flaps, and MMC duration >1 minute were associated with decreased risk of surgical failure. Concurrent phacoemulsification at the time of trabeculectomy did not alter tonometric success or rate of complications. CONCLUSIONS: In phakic patients with PACG, trabeculectomy with MMC significantly reduces IOP and number of glaucoma medications at 12 months without change in visual acuity. However, success rates are modest when based on more demanding tonometric criteria.

Springelkamp H, Höhn R, Mishra A, Hysi PG, Khor C-C, Loomis SJ, Bailey JCN, Gibson J, Thorleifsson G, Janssen SF, Luo X, Ramdas WD, Vithana E, Nongpiur ME, Montgomery GW, Xu L, Mountain JE, Gharahkhani P, Lu Y, Amin N, Karssen LC, Sim K-S, van Leeuwen EM, Iglesias AI, Verhoeven VJM, Hauser MA, Loon S-C, Despriet DDG, Nag A, Venturini C, Sanfilippo PG, Schillert A, Kang JH, Landers J, Jonasson F, Cree AJ, van Koolwijk LME, Rivadeneira F, Souzeau E, Jonsson V, Menon G, Menon G, Weinreb RN, de Jong PTVM, Oostra BA, Uitterlinden AG, Hofman A, Ennis S, Thorsteinsdottir U, Burdon KP, Burdon KP, Burdon KP, Spector TD, Mirshahi A, Saw S-M, Vingerling JR, Teo Y-Y, Haines JL, Wolfs RCW, Lemij HG, Tai E-S, Jansonius NM, Jonas JB, Cheng C-Y, Aung T, Viswanathan AC, Klaver CCW, Craig JE, Macgregor S, Mackey DA, Lotery AJ, Stefansson K, Bergen AAB, Young TL, Wiggs JL, Pfeiffer N, Wong T-Y, Pasquale LR, Hewitt AW, van Duijn CM, Hammond CJ, Hammond CJ, Hammond CJ, Hammond CJ. Meta-analysis of genome-wide association studies identifies novel loci that influence cupping and the glaucomatous process. Nat Commun 2014;5:4883.Abstract

Glaucoma is characterized by irreversible optic nerve degeneration and is the most frequent cause of irreversible blindness worldwide. Here, the International Glaucoma Genetics Consortium conducts a meta-analysis of genome-wide association studies of vertical cup-disc ratio (VCDR), an important disease-related optic nerve parameter. In 21,094 individuals of European ancestry and 6,784 individuals of Asian ancestry, we identify 10 new loci associated with variation in VCDR. In a separate risk-score analysis of five case-control studies, Caucasians in the highest quintile have a 2.5-fold increased risk of primary open-angle glaucoma as compared with those in the lowest quintile. This study has more than doubled the known loci associated with optic disc cupping and will allow greater understanding of mechanisms involved in this common blinding condition.

Springelkamp H, Iglesias AI, Mishra A, Höhn R, Wojciechowski R, Khawaja AP, Nag A, Wang YX, Wang JJ, Cuellar-Partida G, Gibson J, Cooke Bailey JN, Vithana EN, Gharahkhani P, Boutin T, Ramdas WD, Zeller T, Luben RN, Yonova-Doing E, Viswanathan AC, Yazar S, Cree AJ, Haines JL, Koh JY, Souzeau E, Wilson JF, Amin N, Müller C, Venturini C, Kearns LS, Kang JH, Kang JH, Tham YC, Zhou T, van Leeuwen EM, Nickels S, Sanfilippo P, Liao J, van der Linde H, Zhao W, van Koolwijk LME, Zheng L, Rivadeneira F, Baskaran M, van der Lee SJ, Perera S, de Jong PTVM, Oostra BA, Uitterlinden AG, Fan Q, Hofman A, Tai E-S, Vingerling JR, Sim X, Wolfs RCW, Teo YY, Lemij HG, Khor CC, Willemsen R, Lackner KJ, Aung T, Jansonius NM, Montgomery G, Wild PS, Young TL, Burdon KP, Hysi PG, Pasquale LR, Wong TY, Klaver CCW, Hewitt AW, Jonas JB, Mitchell P, Lotery AJ, Foster PJ, Vitart V, Pfeiffer N, Craig JE, Mackey DA, Hammond CJ, Wiggs JL, Cheng C-Y, van Duijn CM, Macgregor S. New insights into the genetics of primary open-angle glaucoma based on meta-analyses of intraocular pressure and optic disc characteristics. Hum Mol Genet 2017;Abstract

Primary open-angle glaucoma (POAG), the most common optic neuropathy, is a heritable disease. Siblings of POAG cases have a ten-fold increase risk of developing the disease. Intraocular pressure (IOP) and optic nerve head characteristics are used clinically to predict POAG risk. We conducted a genome-wide association meta-analysis of IOP and optic disc parameters and validated our findings in multiple sets of POAG cases and controls. Using imputation to the 1000 genomes (1000G) reference set, we identified 9 new genomic regions associated with vertical cup disc ratio (VCDR) and 1 new region associated with IOP. Additionally, we found 5 novel loci for optic nerve cup area and 6 for disc area. Previously it was assumed that genetic variation influenced POAG either through IOP or via changes to the optic nerve head; here we present evidence that some genomic regions affect both IOP and the disc parameters. We characterized the effect of the novel loci through pathway analysis and found that pathways involved are not entirely distinct as assumed so far. Further, we identified a novel association between CDKN1A and POAG. Using a zebrafish model we show that six6b (associated with POAG and optic nerve head variation) alters the expression of cdkn1a In summary, we have identified several novel genes influencing the major clinical risk predictors of POAG and showed that genetic variation in CDKN1A is important in POAG risk.

Stacy R, Huttner K, Watts J, Peace J, Wirta D, Walters T, Sall K, Seaman J, Ni X, Prasanna G, Mogi M, Adams C, Yan J-H, Wald M, He Y, Newton R, Kolega R, Grosskreutz C. A Randomized, Controlled Phase I/II Study to Evaluate the Safety and Efficacy of MGV354 for Ocular Hypertension or Glaucoma. Am J Ophthalmol 2018;192:113-123.Abstract
PURPOSE: To assess the clinical safety, tolerability, and efficacy of topically administered MGV354, a soluble guanylate cyclase (sGC) activator, in patients with ocular hypertension (OH) or glaucoma. DESIGN: Double-masked, randomized, and vehicle-controlled study. METHODS: Parts 1 and 2 evaluated safety and tolerability to identify the maximum tolerated dose (MTD) of once-daily MGV354 in 32 healthy volunteers (Part 1) and 16 patients with OH or glaucoma (Part 2) at a single clinical site. Part 3 was a multisite trial that evaluated intraocular pressure (IOP)-lowering efficacy of the MTD administered nightly for 1 week in 50 patients with minimum IOP of 24 mm Hg at 8 AM, with a main outcome measure of mean diurnal IOP at day 8 compared to baseline (ClinicalTrials.govNCT02743780). RESULTS: There was no difference in favor of MGV354 for IOP lowering; change from baseline to day 8 in mean diurnal IOP was -0.6 mm Hg for MGV354-treated patients and -1.1 mm Hg for vehicle-treated patients in Part 3, with a confidence interval of -0.7 to 1.7. The most common adverse events reported after MGV354 administration were conjunctival and ocular hyperemia. CONCLUSIONS: Overall, MGV354 0.1% demonstrated no statistically significant effect compared to vehicle in lowering IOP based on the study's main outcome measure. MGV354 produced ocular hyperemia consistent with its pharmacology.

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