The African Descent and Glaucoma Evaluation Study (ADAGES): predictors of visual field damage in glaucoma suspects

Time to Glaucoma Progression Detection by Optical Coherence Tomography and Visual Field in Glaucoma Individuals of African Descent

PURPOSE

To examine the time to glaucoma progression detection by retinal nerve fiber layer thickness (RNFLT) and visual field (VF) among individuals of African descent (AD).

DESIGN

Retrospective cohort study.

METHODS

This multicenter study included eyes with glaucoma from individuals of AD from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study with ≥2 years/5 visits of optic nerve head RNFLT and 24-2 VF examinations.

INTERVENTION OR OBSERVATION PROCEDURE

Rates of VF mean deviation (MD) and RNFLT worsening were analyzed using linear mixed-effects models, and longitudinal data were simulated using the variability estimates.

MAIN OUTCOME MEASURE

The simulated time to detect trend-based glaucoma progression was assessed with assumed rates of VF MD and RNFLT change derived from the cohort (25th, 50th, and 75th percentile [as p25, median, and p75] slopes and mean slopes). Severity-stratified analyses were also performed.

RESULTS

We included 184 eyes from 128 subjects of AD (mean baseline age 63.4 years; VF MD -4.2 dB; RNFLT 80.2 µm). The p25, median, mean, and p75 rates of change were -0.43, -1.01, -1.15, and -1.64 µm per year for RNFLT, and 0.00, -0.21, -0.30, and -0.51 dB per year for VF MD, respectively. Compared with VF MD, RNFLT showed an overall shorter mean time to progression detection (time difference 0.4-1.7 years), with the mean rates showing the largest difference (RNFLT 5.2 years vs VF MD 6.9 years). Similarly, we found an overall shorter time to detect RNFLT progression, compared with that of VF MD progression, in eyes with mild glaucoma (≥1 year earlier) and in eyes with moderate to advanced glaucoma (∼0.5 year earlier).

CONCLUSIONS

Computer simulation showed a potentially shorter time to detect RNFLT progression than VF MD progression in eyes from individuals of AD. Our findings support the importance of using RNFLT to detect progressive glaucoma in individuals of AD.

Long-term variability of retinal nerve fibre layer thickness measurement in patients with glaucoma of African and European descents

BACKGROUND

To examine long-term retinal nerve fibre layer thickness (RNFLT) variability and associated clinical factors in African (AD) and European descent (ED) individuals with glaucoma.

METHODS

This retrospective cohort study included glaucoma eyes of AD and ED from Diagnostic Innovations in Glaucoma Study/The African Descent and Glaucoma Evaluation Study with ≥4 visits/2 years of follow-up. We calculated optic nerve head RNFLT variability per-examination/visit as the absolute error of its residuals across follow-up. Full, baseline and parsimonious linear-mixed models were fit to evaluate the effects of clinical factors (demographics and ocular characteristics, prior/intervening glaucoma surgeries and cataract extraction (CE), RNFLT thinning rate, scan quality, visit/testing frequency, etc) on RNFLT variability in both races.

RESULTS

There were 376 and 625 eyes (226 and 349 participants) of AD and ED, and the mean (95% CI) RNFLT variability was 1.62 (1.52, 1.71) µm and 1.42 (1.34, 1.50) µm, respectively (p=0.002). AD and ED had some shared predictors of RNFLT variability, including intraocular pressure fluctuation and scan quality, although the effects varied (p<0.05). In both races, intervening CE was most strongly correlated with higher RNFLT variability (β: 0.24-0.92, p<0.05). After excluding eyes with intervening CE, RNFLT variability was reduced and the small racial difference was no longer significant (AD: 1.40 (1.31, 1.48) µm vs ED: 1.34 (1.27, 1.40) µm; p=0.280).

CONCLUSIONS

Although some predictors were identified, long-term RNFLT variability appeared small for both AD and ED eyes. Moreover, the racial difference did not remain once intervening CE, the strongest predictor of variability, was eliminated. Our findings inform on strategies to optimise structural assessment and suggest that, when accounting for relevant factors, RNFLT is reliable across races.

Association Between Sociodemographic Factors and Self-reported Glaucoma in the National Health Interview Survey: A Population-Based Analysis

PURPOSE

To investigate the association between social determinants of health (SDH) in the domains of social and community context, education access, environmental context, economic stability, and healthcare access, with glaucoma prevalence.

DESIGN

Cross-sectional study.

METHODS

The study population consisted of adult participants who answered glaucoma-related questions on the 2017 National Health Interview Survey (NHIS), the most recent iteration that includes glaucoma-related questions. The main outcome measures included the relationships between SDH-related factors and self-reported glaucoma diagnosis as well as self-reported glaucomatous vision loss were examined using univariable and multivariable regression models.

RESULTS

In total, 26,696 of 26,742 (99.83%) NHIS respondents were included, of whom 880 (3.30%) reported a glaucoma diagnosis and 275 (1.03%) reported glaucomatous vision loss. Participants were predominantly middle-aged (50.95 ± 18.60 years), female (54.75%), and non-Hispanic White (70.49%). In age-adjusted multivariable regression (n = 25,456), non-Hispanic Black race (odds ratio [OR] = 1.87, 99% CI = [1.37, 2.55], P < .001, compared to non-Hispanic White race) and poor health status (OR = 1.54, 99% CI = [1.00, 2.37], P = .01, compared to good health status) were significant predictors of glaucoma diagnosis. For glaucomatous vision loss, having an income below the poverty threshold (OR = 2.41, 99% CI = [1.12, 5.20], P = .003, compared to income ≥5 times the poverty threshold) was the only significant predictor in univariable analyses. No SDH-related factors were significantly associated with glaucomatous vision loss in multivariable analysis (n = 848). Multicollinearity was minimal (variation inflation factor<1.6 for all independent variables).

CONCLUSIONS

Non-Hispanic Black race and poor health status were associated with self-reported glaucoma diagnosis. Physicians and policymakers may consider SDH when assessing clinical risk and designing public health interventions.

The Impact of Social Vulnerability on Structural and Functional Glaucoma Severity, Worsening, and Variability

PURPOSE

To determine the associations between social vulnerability index (SVI) and baseline severity, worsening, and variability of glaucoma, as assessed by visual field (VF) and OCT.

DESIGN

Retrospective longitudinal cohort study.

PARTICIPANTS

Adults with glaucoma or glaucoma suspect status in 1 or both eyes. Visual fields were derived from 7897 eyes from 4482 patients, while OCTs were derived from 6271 eyes from 3976 patients. All eyes had a minimum of 5 tests over follow-up using either the Humphrey Field Analyzer or the Cirrus HD-OCT.

METHODS

Social vulnerability index, which measures neighborhood-level environmental factors, was linked to patients' addresses at the census tract level. Rates of change in mean deviation (MD) and retinal nerve fiber layer (RNFL) thickness were computed using linear regression. The slope of the regression line was used to assess worsening, while the standard deviation of residuals was used as a measure of variability. Multivariable linear mixed-effects models were used to investigate the impact of SVI on baseline, worsening, and variability in both MD and RNFL. We further explored the interaction effect of mean intraocular pressure (IOP) and SVI on worsening in MD and RNFL.

MAIN OUTCOME MEASURES

Glaucoma severity defined based on baseline MD and RNFL thickness. Worsening defined as MD and RNFL slope. Variability defined as the standard deviation of the residuals obtained from MD and RNFL slopes.

RESULTS

Increased (worse) SVI was significantly associated with worse baseline MD (β = -1.07 dB, 95% confidence interval [CI]: [-1.54, -0.60]), thicker baseline RNFL (β = 2.46 μm, 95% CI: [0.75, 4.17]), greater rates of RNFL loss (β = -0.12 μm, 95% CI: [-0.23, -0.02]), and greater VF variability (β = 0.16 dB, 95% CI: [0.07, 0.24]). Having worse SVI was associated with worse RNFL loss with increases in IOP (βinteraction = -0.07, 95% CI: [-0.12, -0.02]).

CONCLUSIONS

Increased SVI score is associated with worse functional (VF) loss at baseline, higher rates of structural (OCT) worsening over time, higher VF variability, and a greater effect of IOP on RNFL loss. Further studies are needed to enhance our understanding of these relationships and establish their cause.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Social Factors Associated with the Risk of Glaucoma Suspect Conversion to Glaucoma: Analysis of the Nationwide All of Us Program

PURPOSE

To examine social factors associated with the 5-year risk of glaucoma suspects (GS) converting to open-angle glaucoma (OAG).

DESIGN

Retrospective cohort analysis.

SUBJECTS

We screened for participants diagnosed with GS in the All of Us database. Cases that converted to OAG within 5 years of GS diagnosis (the "conversion group") were compared with control cases that did not convert.

METHODS

Demographic, socioeconomic and health-care utilization data of the cases were extracted and compared between the conversion group and the control group. Multivariable Cox proportional hazards modeling was used to identify potential factors associated with the risk of conversion.

MAIN OUTCOME MEASURES

Hazard ratios (HRs) of significant factors associated with the risk of conversion.

RESULTS

A total of 5274 GS participants were identified, and 786 (15%) cases converted to OAG within 5-year follow-up. The 2 groups showed significant differences in age, race, gender, employment status, income/education level, history of intraocular surgery, and health-care utilization patterns. In the multivariable model, African American/Black race (HR : 1.70 [95% confidence interval (CI) 1.44-2.00]), older age at GS diagnosis (1.17 [95% CI 1.09-1.25]), male gender (1.30 [95% CI 1.13-1.50], no history of recreational drug use (1.23 [1.07-1.42]), history of intraocular surgery (1.60 [95% CI 1.02-1.53]), and having more reasons for delayed health-care access (2.27 [95% CI 1.23-4.18]) were associated with a greater hazard of conversion, while being employed (0.71 [95% CI 0.60-0.86]) was associated with a smaller hazard of conversion (P < 0.05 for all).

CONCLUSIONS

Several social factors were associated with the conversion from GS to OAG, which may help to identify patients at higher risk of disease progression. Future studies are needed to examine the basis for these findings and the potential interventions that could address them.

FINANCIAL DISCLOSURES

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Understanding racial disparities of glaucoma

PURPOSE OF REVIEW

Increased prevalence, earlier onset, and more rapid progression to vision loss from glaucoma has demonstrated racial disparity in numerous studies over decades. Precise etiologies of these important differences among patients of African and Hispanic ancestral background have not been elucidated. This review focuses on currently available epidemiologic/population, genetic, socioeconomic and physiologic studies of racial disparities in this blinding disease.

RECENT FINDINGS

In depth reviews of several landmark studies of glaucoma prevalence in various racial groups have highlighted potential challenges of lack of recruitment of diverse populations in genetic studies and clinical trials, challenges of racial stratification of subjects, and the impact of socioeconomic variables.

SUMMARY

Through a more comprehensive analysis of racial disparities of glaucoma, both clinicians and researchers may provide more effective population screening and management with a holistic approach for individualized patient care to provide improved outcomes. Future studies of interventions in sociodemographic factors and genetic/physiologic variables that influence the prevalence, access, and consequential vision loss from glaucoma will be crucial to minimize/eliminate racial disparities and improve outcomes for all.

Clinical Factors Associated With Long-Term OCT Variability in Glaucoma

PURPOSE

To examine clinical factors associated with long-term optical coherence tomography (OCT)-measured retinal nerve fiber layer thickness (RNFLT) variability in glaucoma.

STUDY DESIGN

Retrospective cohort study.

METHODS

Glaucoma eyes from Diagnostic Innovations in Glaucoma Study (DIGS)/the African Descent and Glaucoma Evaluation Study (ADAGES) with ≥2-years and 4-visit follow-up were included. RNFLT variability was calculated per visit as the absolute error of optic nerve head RNFLT residuals across longitudinal follow-up. Clinical factors examined included general demographics, baseline ocular measurements, prior and intervening cataract extraction (CE) or glaucoma surgery, scan quality, baseline RNFLT and RNFLT thinning rate, follow-up duration, and visit/testing frequency. Three multivariable linear mixed models (full model, baseline model, and parsimonious model) were fit to evaluate the effects of clinical factors on RNFLT variability, with 10-fold cross-validation to estimate real-world model performance.

RESULTS

A total of 1140 eyes (634 patients) were included. The overall mean (95% CI) RNFLT variability was 1.51(1.45, 1.58) µm. Across different models, African American race (β [standard error {SE} = 0.18 [0.06]), intervening CE (β [SE] = 0.52 [0.07]), intervening glaucoma surgeries (β [SE] = 0.15 [0.03]), and more positive RNFLT thinning rate (β [SE] = 0.06 [0.02] per 1 µm/y more positive) showed consistent association with greater RNFLT variability, whereas more frequent visits/testing (β [SE] = -0.11[0.05] per 1 visit/y higher) was associated with smaller RNFLT variability (P < .05 for all).

CONCLUSIONS

Relevant clinical factors affecting long-term RNFLT variability in glaucoma were identified. These data enhance the evaluation of longitudinal structural change. Increasing the testing frequency, especially in eyes at risk for higher measurement variability, and resetting of baseline imaging after intervening procedures may help to more reliably detect OCT progression.

Paving the way while playing catch up: mitochondrial genetics in African ancestry primary open-angle glaucoma

Glaucoma, the leading cause of irreversible blindness worldwide, disproportionately affects individuals of African descent. Specifically, previous research has indicated that primary open-angle glaucoma (POAG), the most common form of disease, is more prevalent, severe, early-onset, and rapidly-progressive in populations of African ancestry. Recent studies have identified genetic variations that may contribute to the greater burden of disease in this population. In particular, mitochondrial genetics has emerged as a profoundly influential factor in multiple neurodegenerative diseases, including POAG. Several hypotheses explaining the underlying mechanisms of mitochondrial genetic contribution to disease progression have been proposed, including nuclear-mitochondrial gene mismatch. Exploring the fundamentals of mitochondrial genetics and disease pathways within the understudied African ancestry population can lead to groundbreaking advancements in the research and clinical understanding of POAG. This article discusses the currently known involvements of mitochondrial genetic factors in POAG, recent directions of study, and potential future prospects in mitochondrial genetic studies in individuals of African descent.

Association of Glaucoma with the Risk of Peripheral Arterial Occlusive Disease: A Retrospective Population-Based Cohort Study

This study aimed to investigate the potential association between glaucoma and peripheral arterial occlusive disease. The study recruited patients, including 101,309 with glaucoma and 1,860,528 without a glaucoma diagnosis, from a population of 2 million patients in the Longitudinal Health Insurance Database. Propensity score matching was performed between the two groups, matching for age, sex, and comorbidities. In total, 95,575 patients with glaucoma and 95,575 patients without glaucoma were analyzed for their risk of developing peripheral arterial occlusive disease. The analysis of the data revealed that the glaucoma group had a higher incidence density (ID = 4.13) of peripheral arterial occlusive disease than the non-glaucoma group (ID = 3.42). The relative risk for the glaucoma group was 1.21 (95% C.I. = 1.15-1.28). Cox proportional hazard model analysis indicated that the glaucoma group had a higher risk of developing peripheral arterial occlusive disease (HR = 1.18; 95% C.I. = 1.12-1.25). The subgroup analysis of the risk of PAOD showed that the glaucoma group had a higher risk of developing peripheral arterial occlusive disease in the age group of 20 to 39 (p for interaction = 0.002). In conclusion, patients with glaucoma were associated with a higher risk of subsequent peripheral arterial occlusive disease compared with those without a diagnosis of glaucoma.

A comparison of peripapillary vessel density between subjects with normal-tension glaucoma and primary open-angle glaucoma with similar extents of glaucomatous damage

The purpose of this study was to identify differences in retinal microvasculature impairments between patients with normal-tension glaucoma (NTG) and those with primary open-angle glaucoma (POAG) with similar extents of structural and visual field damage. Participants with glaucoma-suspect (GS), NTG, POAG, and normal controls were consecutively enrolled. Peripapillary vessel density (VD) and perfusion density (PD) were compared among the groups. Linear regression analyses were performed to identify the relationship between VD, PD and visual field parameters. The VDs of the full areas were 18.3 ± 0.7, 17.3 ± 1.7, 16.5 ± 1.7, and 15.8 ± 2.3 mm^-1 in the control, GS, NTG, and POAG groups, respectively (P < 0.001). The VDs of the outer and inner areas and the PDs of all areas also differed significantly among the groups (all P < 0.001). In the NTG group, the VDs of the full, outer, and inner areas were significantly associated with all visual field parameters including the mean deviation (MD), pattern standard deviation (PSD), and visual field index (VFI). In the POAG group, the VDs of the full and inner areas were significantly associated with PSD and VFI but not with MD. In conclusion, with similar degrees of retinal nerve fiber layer thinning and visual field damage in both groups, the POAG group showed a lower peripapillary VD and PD than the NTG group. VD and PD were significantly associated with visual field loss.

Racial and Ethnic Differences in the Roles of Myopia and Ocular Biometrics as Risk Factors for Primary Open-Angle Glaucoma

Purpose

Assess how the roles of refractive error (RE) and ocular biometrics as risk factors for primary open-angle glaucoma (POAG) differ by race and ethnicity.

Methods

Data from the Los Angeles Latino Eye Study (LALES) and the Chinese American Eye Study (CHES), two population-based epidemiological studies, were retrospectively analyzed. Multivariable logistic regression and interaction term analyses were performed to assess relationships between POAG and its risk factors, including RE and axial length (AL), and to assess effect modification by race/ethnicity.

Results

Analysis included 7601 phakic participants of LALES (47.3%) and CHES (52.7%) with age ≥ 50 years. Mean age was 60.6 ± 8.3 years; 60.9% were female. The prevalence and unadjusted risk of POAG were higher in LALES than CHES (6.0% and 4.0%, respectively; odds ratio [OR] = 1.55; P < 0.001). In the multivariable analysis, significant risk factors for POAG included Latino ethnicity (OR = 2.25; P < 0.001), refractive myopia (OR = 1.54 for mild, OR = 2.47 for moderate, OR = 3.94 for high compared to non-myopes; P ≤ 0.003), and longer AL (OR = 1.37 per mm; P < 0.001). AL (standardized regression coefficient [SRC] = 0.3) was 2.7-fold more strongly associated with POAG than high myopia status (SRC = 0.11). There was no modifying effect by race/ethnicity on the association between RE (per diopter) or AL (per millimeter) and POAG (P = 0.49).

Conclusions

Although the POAG risk conferred by myopic RE and longer AL is similar between Latino and Chinese Americans, the difference in POAG prevalence between the two groups is narrowed by higher myopia prevalence among Chinese Americans. Racial/ethnic populations with higher myopia incidence may become disproportionately affected by POAG in the context of the global myopia epidemic.

Comparison of Ocular Biomery in Primary Open Angle Glaucoma and Non-glaucoma in South West Nigeria

Background

Glaucoma is a public health problem in Nigeria. The number of individuals affected by glaucoma in Nigeria is much higher than the individuals known to have the disease. Ocular parameters such as intraocular pressure, central cornea thickness, axial length and refractive error have all been documented as risk factors of glaucoma especially among Caucasians and African Americans, with little documentation in Africa where there's an alarming rate of blindness.

Aim and Objectives

To compare central cornea thickness (CCT), intraocular pressure (IOP), axial length (AL) and refractive state in participants with primary open angle glaucoma (POAG) and non-glaucoma in South-West Nigeria.

Materials and Methods

This hospital-based case-control study was carried out among 184 newly diagnosed POAG and non-glaucoma adult participants attending the outpatient clinic of Eleta eye institute. The CCT, IOP, AL and refractive state were measured in each participant. Test of significance between proportions in categorical variables were assessed using chi square test (χ2) in both groups. The means were compared using independent t-test while correlation between parameters were analyzed using Pearson correlation coefficient.

Results

The mean age of the POAG participants was 57.16 + 13.3 years and the mean age of the non-glaucoma participants was 54.15 + 13.4 years. The mean IOP in the POAG group was 30.2 + 8.9mmHg while non- glaucoma group was 14.2 + 2.6mmHg (P < 0.001), other ocular parameters were not significantly different in both groups. In the POAG group, decreased spherical equivalent refractive error (i.e increasing myopia) was significantly associated with increased axial length (r= -0.252, P = 0.01), but not significant in the non- glaucoma group. However, in the non-glaucoma group, central cornea thickness increased with increasing intraocular pressure (r= 0.305, P = 0.003), which was not significant in the glaucoma group.

Conclusion

Patients with POAG had much higher IOP and thus, IOP remains a significant risk factor in its development. There was a significant relationship between refractive state and axial length in the POAG group while a significant relationship was identified between central cornea thickness and intraocular pressure in the non- glaucoma group.

Association of Rates of Ganglion Cell and Inner Plexiform Thinning With Development of Glaucoma in Eyes With Suspected Glaucoma

Importance

In eyes with suspected glaucoma, it is clinically relevant to find diagnostic tests for the risk of development of perimetric glaucoma.

Objective

To investigate the association between rates of ganglion cell/inner plexiform layer (GCIPL) and circumpapillary retinal nerve fiber layer (cpRNFL) thinning and the development of perimetric glaucoma in eyes with suspected glaucoma.

Design, Setting, and Participants

This observational cohort study used data collected in December 2021 from a tertiary center study and a multicenter study. Participants with suspected glaucoma were followed up for 3.1 years. The study was designed in December 2021 and finalized in August 2022.

Exposures

Development of perimetric glaucoma was defined as having 3 consecutive results showing abnormal visual fields. Using linear mixed-effect models, rates of GCIPL were compared between eyes with suspected glaucoma that did and did not develop perimetric glaucoma. A joint longitudinal multivariable survival model was used to investigate the performance of rates of GCIPL and cpRNFL thinning in predicting the risk of developing perimetric glaucoma.

Main Outcomes and Measures

Rates of GCIPL thinning and hazard ratio (HR) of developing perimetric glaucoma.

Results

Among a total of 462 participants, the mean (SD) age was 63.3 (11.1) years, and 275 patients (60%) were female. Of 658 eyes, 153 eyes (23%) developed perimetric glaucoma. The mean rates of GCIPL thinning were faster in eyes that developed perimetric glaucoma (-1.28 vs -0.66 μm/y for minimum GCIPL thinning; difference, -0.62; 95% CI, -1.07 to -0.16; P = .02). Based on the joint longitudinal survival model, every 1-μm/y faster rate of minimum GCIPL and rate of global cpRNFL thinning were associated with a 2.4 and 1.9 higher risk of developing perimetric glaucoma, respectively (HR, 2.4; 95% CI, 1.8 to 3.2, and HR, 1.99; 95% CI, 1.76 to 2.22, respectively; P < .001). Among the predictive factors, African American race (HR, 1.56; 95% CI, 1.05 to 2.34; P = .02), male sex (HR, 1.47; 95% CI, 1.02 to 2.15; P = .03), 1-dB higher baseline visual field pattern standard deviation (HR, 1.73; 95% CI, 1.56 to 1.91; P < .001), and 1-mm Hg higher mean intraocular pressure during follow-up (HR, 1.11; 95% CI, 1.05 to 1.17; P < .001) were associated with higher risk of developing perimetric glaucoma.

Conclusions and Relevance

This study found that faster rates of GCIPL and cpRNFL thinning were associated with higher risks of developing perimetric glaucoma. Rates of cpRNFL thinning and specifically GCIPL thinning may be useful measures for monitoring eyes with suspected glaucoma.

Development and Evaluation of a Rules-based Algorithm for Primary Open-Angle Glaucoma in the VA Million Veteran Program

The availability of electronic health record (EHR)-linked biobank data for research presents opportunities to better understand complex ocular diseases. Developing accurate computable phenotypes for ocular diseases for which gold standard diagnosis includes imaging remains inaccessible in most biobank-linked EHRs. The objective of this study was to develop and validate a computable phenotype to identify primary open-angle glaucoma (POAG) through accessing the Department of Veterans Affairs (VA) Computerized Patient Record System (CPRS) and Million Veteran Program (MVP) biobank. Accessing CPRS clinical ophthalmology data from VA Medical Center Eye Clinic (VAMCEC) patients, we developed and iteratively refined POAG case and control algorithms based on clinical, prescription, and structured diagnosis data (ICD-CM codes). Refinement was performed via detailed chart review, initially at a single VAMCEC (n = 200) and validated at two additional VAMCECs (n = 100 each). Positive and negative predictive values (PPV, NPV) were computed as the proportion of CPRS patients correctly classified with POAG or without POAG, respectively, by the algorithms, validated by ophthalmologists and optometrists with access to gold-standard clinical diagnosis data. The final algorithms performed better than previously reported approaches in assuring the accuracy and reproducibility of POAG classification (PPV >83% and NPV >97%) with consistent performance in Black or African American and in White Veterans. Applied to the MVP to identify cases and controls, genetic analysis of a known POAG-associated locus further validated the algorithms. We conclude that ours is a viable approach to use combined EHR-genetic data to study patients with complex diseases that require imaging confirmation.

Longitudinal visual field variability and the ability to detect glaucoma progression in black and white individuals

BACKGROUND/AIMS

To investigate racial differences in the variability of longitudinal visual field testing in a 'real-world' clinical population, evaluate how these differences are influenced by socioeconomic status, and estimate the impact of differences in variability on the time to detect visual field progression.

METHODS

This retrospective observational cohort study used data from 1103 eyes from 751 White individuals and 428 eyes from 317 black individuals. Linear regression was performed on the standard automated perimetry mean deviation values for each eye over time. The SD of the residuals from the trend lines was calculated and used as a measure of variability for each eye. The association of race with the SD of the residuals was evaluated using a multivariable generalised estimating equation model with an interaction between race and zip code income. Computer simulations were used to estimate the time to detect visual field progression in the two racial groups.

RESULTS

Black patients had larger visual field variability over time compared with white patients, even when adjusting for zip code level socioeconomic variables (SD of residuals for Black patients=1.53 dB (95% CI 1.43 to 1.64); for white patients=1.26 dB (95% CI 1.14 to 1.22); mean difference: 0.28 (95% CI 0.15 to 0.41); p<0.001). The difference in visual field variability between black and white patients was greater at lower levels of income and led to a delay in detection of glaucoma progression.

CONCLUSION

Black patients had larger visual field variability compared with white patients. This relationship was strongly influenced by socioeconomic status and may partially explain racial disparities in glaucoma outcomes.

Cohort Study of Race/Ethnicity and Incident Primary Open-Angle Glaucoma Characterized by Autonomously Determined Visual Field Loss Patterns

Purpose

We evaluated racial/ethnic differences in primary open-angle glaucoma (POAG) defined by machine-learning–derived regional visual field (VF) loss patterns.

Methods

Participants (N = 209,036) from the Nurses’ Health Study (NHS; 1980–2018), Nurses’ Health Study II (NHS2; 1989–2019), and Health Professionals Follow-Up Study (HPFS; 1986–2018) who were ≥40 years of age and free of glaucoma were followed biennially. Incident POAG cases (n = 1946) with reproducible VF loss were confirmed with medical records. Total deviation information from the earliest reliable glaucomatous VF for each POAG eye (n = 2564) was extracted, and machine learning analyses were used to identify optimal solutions (“archetypes”) for regional VF loss patterns. Each POAG eye was assigned a VF archetype based on the highest weighting coefficient. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using per-eye Cox proportional hazards models.

Results

We identified 14 archetypes: four representing advanced loss patterns, nine of early loss, and one of no VF loss. Compared to non-Hispanic whites, black participants had higher risk of early VF loss archetypes (HR = 1.98; 95% CI, 1.48–2.66) and even higher risk for advanced loss archetypes (HR = 6.17; 95% CI, 3.69–10.32; P-contrast = 0.0002); no differences were observed for Asians or Hispanic whites. Hispanic white participants had significantly higher risks of POAG with paracentral defects and advanced superior loss; black participants had significantly higher risks of all advanced loss archetypes and three early loss patterns, including paracentral defects.

Conclusions

Blacks, compared to non-Hispanic whites, had higher risks of POAG with early central and advanced VF loss.

Translational Relevance

In POAG, risks of VF loss regional patterns derived from machine learning algorithms showed racial differences.

Glaucomatous Visual Field Progression in the African Descent and Glaucoma Evaluation Study (ADAGES): Eleven Years of Follow-up

PURPOSE

To compare the rates of visual field (VF) progression between individuals of Black and White race and to investigate whether treatment effects may help explain differences previously reported between racial groups.

DESIGN

Multicenter prospective observational cohort study.

METHODS

Participants were patients in referral tertiary care glaucoma clinics with open angle glaucoma. Eyes were excluded who had <5 VF tests and <2 years of follow-up or any disease that could affect the optic nerve or the VF. The VF mean deviation (MD) slopes over time (dB/y) were calculated with linear regression models. Socioeconomic variables, rates of glaucoma surgery, medications, treated intraocular pressure (IOP), and central corneal thickness (CCT) were investigated.

RESULTS

A total of 516 eyes were included with a mean (95% CI) follow-up time of 11.0 (range, 10.5-11.5) years and 15.0 (range, 14.1-15.8) visits. Participants of Black race were significantly younger (59.7 vs 66.9 years, P < .01) than those of White race. The mean CCT and socioeconomic variables were similar between Black and White groups (P = 0.20 and P = .56, respectively), as were treatment with topical medications (P = .90) and the rate of VF MD change (-0.24 [-0.31 to -0.17] dB/year vs -0.32 [-0.36 to -0.27], P = .11), despite higher treated mean IOP (14.9 [14.5 to 15.4] vs 14.0 [13.6 to 14.4] mm Hg, P = .03) and fewer trabeculectomies (29.5% vs 50.0%, P < .01) in the Black race group.

CONCLUSIONS

Rates of VF progression were similar despite higher treated IOP in the Black race group. Mitigation of health access disparities in this study may have equalized previously reported different rates of VF progression between racial groups.

Glaucoma Screening Using an iPad-Based Visual Field Test in a West African Population

PURPOSE

To investigate the performance of the Melbourne Rapid Fields (MRF) for use in clinic-based visual field testing in a low-resource setting.

DESIGN

Prospective cross-sectional study.

PARTICIPANTS

One hundred and three participants (66 patients with glaucoma and 37 control participants) attending a clinical appointment at the Tema Eye Center, Tema, Ghana.

METHODS

Patients with glaucoma and control participants underwent MRF and Humphrey Field Analyzer (HFA) testing.

MAIN OUTCOME MEASURES

Mean deviation (MD), pattern standard deviation (PSD), reliability parameters, sensitivity, specificity, and area under the receiver operating characteristic curve.

RESULTS

Mean MD was less negative and mean PSD was more positive on the MRF than the HFA in both groups (all P < 0.001). False-positive and false-negative rates were comparable between methods (P = 0.09 and P = 0.35, respectively). In patients with glaucoma, MD and PSD from the 2 devices were correlated strongly (r = 0.84; P < 0.001) and moderately (r = 0.61; P < 0.001), respectively. Agreement analysis revealed that MRF tended to generate significantly higher MD (bias, 3.3 ± 4.1 dB; P = 0.03) and PSD (bias, 1.9 ± 2.8 dB; P = 0.03) with wide limits of agreement. For detecting moderate to advanced glaucoma, the sensitivity was 60.9% for the MRF and 78.3% for the HFA (P = 0.10); respective specificities were 86.5% and 83.8% (P = 0.76).

CONCLUSIONS

The MRF underestimated MD and overestimated PSD values compared with the HFA. Agreement biases were significant, suggesting a weak agreement between the 2 devices. However, the MRF showed potential for screening in a low-resource setting, particularly for detecting moderate to advanced glaucoma.

Cutaneous melanin and glaucoma: a case control study

Purpose: Previous studies have used subjective assessments to implicate darker skin color as a risk factor for glaucoma. This study used objective measurements to determine whether skin melanin is a risk factor for glaucoma.Methods: In a case-control study conducted at a tertiary eye hospital in Nepal, patients aged 40 years or older from the glaucoma clinic were enrolled as cases and age-matched patients without glaucoma from other clinics at the eye hospital were enrolled as controls. A colorimeter was used to capture melanin measurements in triplicate from the inner arm and forehead of each participant. The exposure variable of interest was the median skin melanin value, in arbitrary units. The outcome of interest was the presence of glaucoma.Results: 100 glaucoma cases and 100 matched controls were enrolled. Agreement between the triplicate melanin measurements was high, with an intra-class correlation of 0.99 (95% CI, 0.99-0.99) for inner arm measurements and 0.97 (95% CI 0.96-0.98) for forehead measurements. Mean inner arm melanin values were 604 units (standard deviation [SD] 177) in cases and 602 units (SD 179) in controls; forehead values were 650 (SD 146) in cases and 652 (SD 152) in controls. After adjusting for sex and country of residence, skin melanin was not associated with the presence of glaucoma (odds ratio 1.04, 95%CI 0.78-1.38 for inner arm values and 0.97, 95%CI 0.70-1.35 for forehead values).Conclusion: This study failed to find a significant association between skin pigmentation and glaucoma.

The Relationship Between Melanin and Glaucoma: A Case-control Study

PRéCIS:: In a case-control study, skin pigmentation was not statistically significantly different when comparing glaucoma patients to those without glaucoma.

PURPOSE

Darker skin color has been implicated as a risk factor for glaucoma based on previous studies' subjective assessments of skin pigmentation. This study used objective measurements to determine whether cutaneous pigmentation is a risk factor for glaucoma.

METHODS

This case-control study was conducted at Menelik II Tertiary Referral Hospital in Addis Ababa, Ethiopia. Patients aged 40 years or older from the glaucoma clinic who were being scheduled for trabeculectomy were enrolled as cases and age-matched patients without glaucoma from other clinics at Menelik II Tertiary Referral Hospital were enrolled as controls. A Dermacatch device was used to capture melanin measurements in triplicate from the inner arm of each participant. The exposure variable of interest was the median of the triplicate skin melanin measurements, in arbitrary units. The outcome of interest was presence of glaucoma.

RESULTS

Agreement between the triplicate inner arm melanin measurements was high, with an intraclass correlation of 0.99 (95% confidence interval, 0.98-0.99). Mean melanin values were 704 units (SD 94) in 76 cases and 694 units (SD 93) in 152 controls. Melanin was not statistically significantly associated with glaucoma after adjusting for sex and season of measurement (ie, dry vs. rainy), with an odds ratio of 1.15 (95% confidence interval, 0.59-2.24) per 100 units of inner arm melanin.

CONCLUSION

This study failed to find a significant association between skin pigmentation and glaucoma using an objective and reproducible assessment of pigmentation.

Waveform parameters of retrobulbar vessels in glaucoma patients with different demographics and disease severity

Introduction:

To identify novel velocity waveform parameters of the ophthalmic artery and central retinal artery by computer-aided image processing of Doppler ultrasonography measurements, and to evaluate correlations between the waveform parameters and different demographics and disease severity of open-angle glaucoma patients.

Methods:

Thirty-six images of 36 open-angle glaucoma patients were considered. A semiautomated image processing code was used to detect the digitalized ophthalmic artery and central retinal artery velocity waveforms and to extract the waveform parameters. Concordance correlation coefficient, two-sample t-test, and Pearson’s correlation coefficient were used to test for similarities, differences, and associations among variables.

Results:

Female glaucoma patients showed a statistically higher ophthalmic artery normalized distance between ascending and descending limb (p = 0.004), hypertensive glaucoma patients a statistically higher ophthalmic artery peak systolic velocity time (p = 0.025), glaucoma patients with hyperlipidemia a statistically higher ophthalmic artery resistivity index (p = 0.023) and a statistically higher ophthalmic artery peak systolic velocity acceleration (p = 0.025), glaucoma patients with cardiovascular diseases a statistically lower central retinal artery normalized distance between ascending and descending limb of the wave (p = 0.033) and a statistically higher central retinal artery period (p = 0.028), and patients with different body mass index a statistically different central retinal artery normalized distance between ascending and descending limb of the wave (p = 0.016). Groups with different disease severity, classified following the Brusini glaucoma staging system 2, showed statistically different central retinal artery normalized distance between ascending and descending limb of the wave (p < 0.001) and central retinal artery period (p = 0.016). No statistical differences were found in regard to race, diabetes status, glaucoma family history, and smoking.

Discussion:

Ophthalmic artery and central retinal artery computer-aided analysis of velocity waveforms could identify novel waveform parameters capable of differentiating among different demographics and disease severity of open-angle glaucoma patients.

Comparison of Peripapillary Capillary Density in Glaucoma Patients of African and European Descent

PURPOSE

To evaluate racial differences in optic nerve head peripapillary capillary density measured by OCT angiography (OCTA) in patients with open-angle glaucoma.

DESIGN

Observational, cross-sectional study.

PARTICIPANTS

Two hundred eighty-four eyes of 195 glaucoma patients and 108 eyes of 58 healthy participants from the Diagnostic Innovations in Glaucoma Study.

METHODS

Global and sectoral circumpapillary capillary density (cpCD) loss in participants of European descent (ED) and African descent (AD) were compared. Areas under the receiver operating characteristic curve (AUROCs) were used to evaluate diagnostic accuracy of cpCD and global circumpapillary retinal nerve fiber layer (cpRNFL) thickness in the 2 groups after adjusting for confounders.

MAIN OUTCOME MEASURES

Peripapillary capillary density and cpRNFL thickness measurements and their estimated loss.

RESULTS

Participants of AD and ED with glaucoma were of similar age and glaucoma severity. After adjusting for age, disc area, and other confounders, significantly lower cpCD was found in ED eyes compared with AD eyes in mild glaucoma (mean, 42.2% [95% confidence interval (CI), 41.2%-43.2%] and 46.5% [95% CI, 44.8%-48.1%], respectively; adjusted difference, 4.4 [95% CI, 2.6-6.2]; P < 0.001) and moderate to advanced glaucoma (mean, 34.7% and 38.5%, respectively; adjusted difference, 4.8 [95% CI, 1.6-8.1]; P = 0.005). Although capillary density loss was greater in all sectors in ED compared with AD participants, a similar sectoral pattern of density loss was observed in both racial groups. Lower mean deviation and older age were associated with lower cpCD in both races in multivariate models. The adjusted AUROC for discriminating between healthy and glaucomatous eyes for cpCD was higher for ED (0.95) compared with AD (0.68) patients (P < 0.001). Sensitivity at 95% specificity in AD participants was lower than in ED participants for cpCD (0.32 [95% CI, 0.11-0.64] vs. 0.83 [95% CI, 0.69-0.93], respectively; P < 0.001).

CONCLUSIONS

Although peripapillary capillary density parameters showed good diagnostic accuracy for detecting glaucoma in ED patients, their diagnostic accuracy was only modest in AD patients. Diagnostic performance of cpCD is race dependent, and clinicians should be aware that it has poorer performance in AD patients.

A multiethnic genome-wide analysis of 44,039 individuals identifies 41 new loci associated with central corneal thickness

Central corneal thickness (CCT) is one of the most heritable human traits, with broad-sense heritability estimates ranging between 0.68 to 0.95. Despite the high heritability and numerous previous association studies, only 8.5% of CCT variance is currently explained. Here, we report the results of a multiethnic meta-analysis of available genome-wide association studies in which we find association between CCT and 98 genomic loci, of which 41 are novel. Among these loci, 20 were significantly associated with keratoconus, and one (RAPSN rs3740685) was significantly associated with glaucoma after Bonferroni correction. Two-sample Mendelian randomization analysis suggests that thinner CCT does not causally increase the risk of primary open-angle glaucoma. This large CCT study explains up to 14.2% of CCT variance and increases substantially our understanding of the etiology of CCT variation. This may open new avenues of investigation into human ocular traits and their relationship to the risk of vision disorders.

The Relationship Between Intraocular Pressure and Rates of Central Versus Peripheral Visual Field Progression

PRECIS

In this longitudinal prospective cohort study of open-angle glaucoma patients, intraocular pressure (IOP) parameters (mean, fluctuation, and maximum) had a similar effect on glaucomatous progression in the central and peripheral visual field (VF) regions.

PURPOSE

To study the effects of IOP on rates of glaucomatous central versus peripheral VF progression.

METHODS

The African Descent and Glaucoma Evaluation Study (ADAGES) is a longitudinal prospective cohort study that recruited patients from 3 centers. A sample of those with established glaucoma were included in this study. The mean peripheral sensitivity (MPS) and the mean central sensitivity (MCS) were defined based upon the average total deviation of the peripheral and central (10 degrees) points of the 24-2 VF, respectively. Progression was based upon central and peripheral change from linear mixed-effects models. The relationships between VF progression and IOP mean, maximum, and fluctuation as continuous variables were also investigated. Main outcome measures were MPS and MCS progression rates.

RESULTS

A total of 452 eyes of 344 patients were studied. The mean number of VFs (SD) for each eye was 13.3 (6.4) over 9.1 (3.7) years. The mean baseline MD was -5.1 (3.9) dB and the mean rate of MD change was -0.26 dB/y [95% confidence interval (CI): -0.33 to -0.20, P<0.001]. Mean rates of MPS (-0.27 dB/y, 95% CI: -0.33 to -0.22, P<0.001) and MCS change (-0.26 dB/y, 95% CI: -0.31 to -0.21, P<0.001) were similar (P=0.351). Mean, fluctuation, and maximum IOP were significantly associated with MPS and MCS (all P<0.025).

CONCLUSIONS

The effect of IOP parameters on VF progression was statistically similar between central and peripheral VF regions.

Ganglion Cell-Inner Plexiform Layer and Retinal Nerve Fiber Layer Changes in Glaucoma Suspects Enable Prediction of Glaucoma Development

PURPOSE

To investigate whether progressive macular ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (RNFL) thinning predict development of visual field (VF) defects in glaucoma suspects.

DESIGN

Retrospective cohort study.

METHODS

This study included 541 eyes of 357 glaucoma suspects with a mean follow-up of 5.7 years. Progressive GCIPL and RNFL thinning were determined using Guided Progression Analysis (GPA) in optical coherence tomography (OCT). The development of VF defect was defined as the presence of three consecutive abnormal VFs. The risk of developing VF defect was evaluated using Cox proportional hazard models.

RESULTS

A total of 74 eyes (13.7%) and 87 eyes (16.1%) showed progressive GCIPL and RNFL thinning by OCT GPA, respectively, and 40 eyes (7.4%) developed VF defects. Eyes with progressive GCIPL (hazard ratio [HR], 7.130; 95% confidence interval [CI], 3.137-16.205) and RNFL (HR, 7.525; 95% CI, 3.272-17.311) thinning showed a significantly higher risk of developing VF defects. The rate of change in the average GCIPL and RNFL thickness was significantly higher in the eyes that developed VF defects (-0.71 and -1.13 μm/y, respectively) than the eyes that did not (-0.19 and -0.27 μm/y, respectively; all P < 0.05). Progressive GCIPL (43.1 vs. 63.1 months, respectively; P < 0.001) and RNFL (50.9 vs. 66.7 months, respectively; P < 0.001) thinning were detected significantly earlier than the development of VF defects.

CONCLUSIONS

Monitoring progressive change in GCIPL, as well as RNFL, effectively predicts the development of VF defects in glaucoma suspects.

Clinical implications of recent advances in primary open-angle glaucoma genetics

Over the last decade, genetic studies, including genome-wide association studies (GWAS), have accelerated the discovery of genes and genomic regions contributing to primary open-angle glaucoma (POAG), a leading cause of irreversible vision loss. Here, we review the findings of genetic studies of POAG published in English prior to September 2019. In total, 74 genomic regions have been associated at a genome-wide level of significance with POAG susceptibility. Recent POAG GWAS provide not only insight into global and ethnic-specific genetic risk factors for POAG susceptibility across populations of diverse ancestry, but also important functional insights underlying biological mechanisms of glaucoma pathogenesis. In this review, we also summarize the genetic overlap between POAG, glaucoma endophenotypes, such as intraocular pressure and vertical cup-disc ratio (VCDR), and other eye disorders. We also discuss approaches recently developed to increase power for POAG locus discovery and to predict POAG risk. Finally, we discuss the recent development of POAG gene-based therapies and future strategies to treat glaucoma effectively. Understanding the genetic architecture of POAG is essential for an earlier diagnosis of this common eye disorder, predictive testing of at-risk patients, and design of gene-based targeted medical therapies none of which are currently available.

Update on the genetics of primary open-angle glaucoma

Affecting nearly 80 million individuals, glaucoma is the number one cause of irreversible blindness in the world. This ocular disease describes a set of optic neuropathies of which primary open angle glaucoma (POAG) is the most common. POAG is associated with progressive visual field deterioration resulting from damage to the optic nerve and loss of retinal ganglion cells. Risk factors for POAG include elevated intraocular pressure, aging, African and Hispanic ancestry, and a positive family history of POAG. Multiple genes have been found to contribute to POAG. Much of POAG genetics and pathology has yet to be explained. Recent genome-wide association studies have identified a large number of novel loci associated with POAG and its endophenotypes. Genomic and proteomic profiling of biofluids has contributed to our knowledge of differential gene expression in POAG. Functional studies both in cell culture and animal models have confirmed the effects of variants and differential gene expression on ocular physiology while in silico analyses have increased our understanding of disease risk and progression so that we might better diagnose and treat this complex genetic illness.

The African Descent and Glaucoma Evaluation Study (ADAGES) III: Contribution of Genotype to Glaucoma Phenotype in African Americans: Study Design and Baseline Data

PURPOSE

To describe the study protocol and baseline characteristics of the African Descent and Glaucoma Evaluation Study (ADAGES) III.

DESIGN

Cross-sectional, case-control study.

PARTICIPANTS

Three thousand two hundred sixty-six glaucoma patients and control participants without glaucoma of African or European descent were recruited from 5 study centers in different regions of the United States.

METHODS

Individuals of African descent (AD) and European descent (ED) with primary open-angle glaucoma (POAG) and control participants completed a detailed demographic and medical history interview. Standardized height, weight, and blood pressure measurements were obtained. Saliva and blood samples to provide serum, plasma, DNA, and RNA were collected for standardized processing. Visual fields, stereoscopic disc photographs, and details of the ophthalmic examination were obtained and transferred to the University of California, San Diego, Data Coordinating Center for standardized processing and quality review.

MAIN OUTCOME MEASURES

Participant gender, age, race, body mass index, blood pressure, history of smoking and alcohol use in POAG patients and control participants were described. Ophthalmic measures included intraocular pressure, visual field mean deviation, central corneal thickness, glaucoma medication use, or past glaucoma surgery. Ocular conditions, including diabetic retinopathy, age-related macular degeneration, and past cataract surgery, were recorded.

RESULTS

The 3266 ADAGES III study participants in this report include 2146 AD POAG patients, 695 ED POAG patients, 198 AD control participants, and 227 ED control participants. The AD POAG patients and control participants were significantly younger (both, 67.4 years) than ED POAG patients and control participants (73.4 and 70.2 years, respectively). After adjusting for age, AD POAG patients had different phenotypic characteristics compared with ED POAG patients, including higher intraocular pressure, worse visual acuity and visual field mean deviation, and thinner corneas (all P < 0.001). Family history of glaucoma did not differ between AD and ED POAG patients.

CONCLUSIONS

With its large sample size, extensive specimen collection, and deep phenotyping of AD and ED glaucoma patients and control participants from different regions in the United States, the ADAGES III genomics study will address gaps in our knowledge of the genetics of POAG in this high-risk population.

Genetic Architecture of Primary Open-Angle Glaucoma in Individuals of African Descent: The African Descent and Glaucoma Evaluation Study III

PURPOSE

To find genetic contributions to glaucoma in African Americans.

DESIGN

Cross-sectional, case-control study.

PARTICIPANTS

One thousand eight hundred seventy-five primary open-angle glaucoma (POAG) patients and 1709 controls, self-identified as being of African descent (AD), from the African Descent and Glaucoma Evaluation Study (ADAGES) III and Wake Forest School of Medicine.

METHODS

MegaChip genotypes were imputed to Thousand Genomes data. Association of single nucleotide polymorphisms (SNPs) with POAG and advanced POAG was tested by linear mixed model correcting for relatedness and population stratification. Genetic risk scores were tested by receiver operator characteristic curves (ROC-AUCs).

MAIN OUTCOME MEASURES

Primary open-angle glaucoma defined by visual field loss without other nonocular conditions (n = 1875). Advanced POAG was defined by age-based mean deviation of visual field (n = 946).

RESULTS

Eighteen million two hundred eighty-one thousand nine hundred twenty SNPs met imputation quality of r2 > 0.7 and minor allele frequency > 0.005. Association of a novel locus, EN04, was observed for advanced POAG (rs185815146 β, 0.36; standard error, 0.065; P < 3×10-8). For POAG, an AD signal was observed at the 9p21 European descent (ED) POAG signal (rs79721419; P < 6.5×10-5) independent of the previously observed 9p21 ED signal (rs2383204; P < 2.3×10-5) by conditional analyses. An association with POAG in FNDC3B (rs111698934; P < 3.9×10-5) was observed, not in linkage disequilibrium (LD) with the previously reported ED SNP. Additional previously identified loci associated with POAG in persons of AD were: 8q22, AFAP1, and TMC01. An AUC of 0.62 was observed with an unweighted genetic risk score comprising 11 SNPs in candidate genes. Two additional risk scores were studied by using a penalized matrix decomposition with cross-validation; risk scores of 50 and 400 SNPs were identified with ROC of AUC = 0.74 and AUC = 0.94, respectively.

CONCLUSIONS

A novel association with advanced POAG in the EN04 locus was identified putatively in persons of AD. In addition to this finding, this genome-wide association study in POAG patients of AD contributes to POAG genetics by identification of novel signals in prior loci (9p21), as well as advancing the fine mapping of regions because of shorter average LD (FNDC3B). Although not useful without confirmation and clinical trials, the use of genetic risk scores demonstrated that considerable AD-specific genetic information remains in these data.

Bruch's membrane opening minimum rim width and retinal nerve fiber layer thickness in a Brazilian population of healthy subjects

Objective

To determine Bruch’s membrane opening (BMO) minimum rim width (MRW) and peripapillary retinal nerve fiber layer thickness (RNFLT) measurements, acquired with optical coherence tomography (OCT) in healthy Brazilian individuals self-reported as African Descent (AD), European Descent (ED) and Mixed Descent (MD).

Methods

260 healthy individuals (78 AD, 103 ED and 79 MD) were included in this cross-sectional study conducted at the Clinics Hospital of the University of Campinas. We obtained optic nerve head (24 radial B scans) and peripapillary retinal nerve fiber layer (3.5-mm circle scan) images in one randomly selected eye of each subject.

Results

After adjustment for BMO area and age, there were no significant differences in mean global MRW (P = 0.63) or RNFLT (P = 0.07) among the three groups. Regionally, there were no significant differences in either MRW or RNFLT in most sectors, except in the superonasal sector, in which both MRW and RNFLT were thinner among ED (P = 0.04, P<0.001, respectively). RNFLT was also thinner in ED in the inferonasal sector (P = 0.009). In all races, global MRW decreased and global RNFLT increased with BMO area. AD subjects had higher rates of global RNFLT decay with age (-0.32 μm/year) compared to ED and MD subjects (-0.10 μm/year and -0.08 μm/year, respectively; P = 0.01 and P = 0.02, respectively).

Conclusions and relevance

While we found no significant differences in global MRW and RNFLT among the three races, age-related thinning of the RNFLT was significantly higher in the AD subgroup, which warrants further study.

Racial Differences in Rate of Change of Spectral-Domain Optical Coherence Tomography-Measured Minimum Rim Width and Retinal Nerve Fiber Layer Thickness

PURPOSE

To compare race-related differences in estimated rate of change of Bruch's membrane opening-minimum rim width (BMO-MRW) and circumpapillary retinal nerve fiber layer thickness (RNFLT) in healthy, glaucoma suspect, and glaucoma eyes of individuals of European (ED) and African descent (AD).

DESIGN

Prospective cohort study.

METHODS

This study investigated rate of change of BMO-MRW and RNFLT in 124 healthy, 227 glaucoma suspect, and 177 glaucoma eyes followed for approximately 3 years and tested with optical coherence tomography every 6 months. Suspect eyes had a history of untreated intraocular pressure (IOP) ≥ 22 mm Hg or suspicion of glaucoma by optic disc photograph assessment without repeatable abnormal standard automated perimetry (SAP) results. Glaucoma eyes had repeatable abnormal SAP results (GHT ONL or PSD ≤ 5%). Mixed-effects models were used to estimate the rate of change after controlling for age, mean follow-up IOP, central corneal thickness, axial length, and BMO area.

RESULTS

A race-related difference in rate of change of global BMO-MRW but not average RNFLT in suspect eyes was observed. Rate of change of BMO-MRW was -1.82 μm/year and -2.20 μm/year in ED and AD suspect eyes, respectively (P = .03). Rate of change of RNFLT was -0.64 μm/year and -0.75 μm/year in ED and AD suspect eyes, respectively (P = .75). No race-related differences in change rate were found in healthy or glaucoma eyes.

CONCLUSION

Race is an important consideration when assessing structural change, particularly minimum rim width, in glaucoma suspect eyes. Differences in rate of structural change may help explain racial disparities in glaucoma susceptibility.

Automated Beta Zone Parapapillary Area Measurement to Differentiate Between Healthy and Glaucoma Eyes

PURPOSE

To evaluate whether automated assessment of beta zone parapapillary atrophy (βPPA) area can differentiate between glaucomatous and healthy eyes of varying axial lengths (AL).

DESIGN

Cross-sectional study.

METHODS

βPPA was automatically identified in glaucoma and healthy eyes with enhanced-depth imaging optical coherence tomography (OCT) optic nerve head (ONH) radial B-scans. Associations with AL and the presence of glaucoma were assessed. Manually delineated βPPA on individual OCT ONH B-scans of 35 eyes from the Diagnostic Innovations in Glaucoma Study served to validate the automated method.

RESULTS

One hundred fifty-three glaucoma eyes (mean ± standard deviation) (visual field mean deviation, -5.0 ± 6.4 dB and mean AL, 25.1 ± 1.1 mm) and 73 healthy eyes (visual field mean deviation, 0.1 ± 1.4 dB and mean AL, 24.1 ± 1.1 mm) were included. In multivariable analysis, larger βPPA area was significantly associated with a diagnosis of glaucoma after controlling for age, central corneal thickness, and AL. Moreover, in multivariable analysis, the odds of having glaucoma were doubled for each 0.2 mm² larger βPPA area. The age- and AL-adjusted area under the receiver operating characteristic curve (95% confidence interval) of βPPA area for differentiating between glaucoma and healthy eyes was 0.75 (0.68-0.81). Agreement for the location of the Bruch membrane opening and the location of retinal pigment epithelium tips was stronger between the automated technique and each individual observer than it was between the 2 observers.

CONCLUSIONS

Larger βPPA area, as determined by automated OCT assessment, is significantly associated with a diagnosis of glaucoma, even after adjusting for age and AL, and may aid in differentiating healthy from glaucomatous eyes.

Inter-eye Asymmetry of Optical Coherence Tomography Angiography Vessel Density in Bilateral Glaucoma, Glaucoma Suspect, and Healthy Eyes

PURPOSE

To investigate inter-eye retinal vessel density asymmetry in healthy, glaucoma suspect, and mild-to-moderate glaucoma subjects, and its potential utility for early detection of glaucomatous damage.

DESIGN

Cross-sectional study.

METHODS

In 153 subjects including 55 healthy, 32 glaucoma suspect, and 66 glaucoma subjects enrolled in the Diagnostic Innovations in Glaucoma Study (DIGS), vessel density was obtained from optical coherence tomography angiography (OCT-A) macular and optic nerve head scans. Thickness of peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell complex (mGCC) was measured with spectral-domain optical coherence tomography (SD-OCT) scans. Inter-eye asymmetry was calculated by taking the absolute value of difference in vessel density and thickness between the right and left eyes.

RESULTS

Inter-eye retinal vessel density asymmetry parameters were significantly different among the 3 groups. Glaucoma suspects had significantly higher peripapillary and macular inter-eye vessel density asymmetries compared to healthy groups in univariate (1.1% vs 2.0%, P = .014 and 1.2% vs 2.5%, P = .027, respectively) and multivariate analyses (P = .007 and P = .038, respectively). No significant differences in asymmetry of thickness parameters were found between glaucoma suspect and healthy groups (all P > .718). However, significant differences in asymmetry of thickness parameters between glaucoma suspects and glaucoma patients (P < .01) were found for all parameters.

CONCLUSION

Inter-eye vessel density asymmetry can be quantified by OCT-A measurement. Glaucoma suspects have significantly greater vessel density asymmetry than healthy eyes. Longitudinal studies are needed to better characterize the relationship of vessel density asymmetry with the development and progression of glaucoma.

The distribution of retinal nerve fiber layer thickness and associations with age, refraction, and axial length: the Gutenberg health study

PURPOSE

To evaluate the distribution of peripapillary retinal nerve fiber layer thickness as measured by optical coherence tomography and its associations with ocular parameters in a population-based setting.

METHODS

In the population-based Gutenberg Health Study, 1974 subjects from the Mainz-Bingen region were scheduled for ophthalmologic examinations, including visual acuity, refraction, tonometry, biometry, and measurements of peripapillary retinal nerve fiber layer thickness (pRNFL) by optical coherence tomography (SD-OCT, Spectralis®, Heidelberg Engineering, Germany). The associated factors in the global and sectoral pRNFL data were analyzed using multivariable linear mixed models related to age, sex, and ocular parameters.

RESULTS

Advanced age and longer axial length were associated with a thinner pRNFL, whereas pRNFL thickness was independent of sex, intraocular pressure (IOP), and central corneal thickness (CCT). Spherical equivalent was positively associated with pRNFL thickness, except in the temporal pRNFL sector.

CONCLUSIONS

In this large, population-based study, pRNFL thickness decreased with age. Longer eyes had thinner pRNFL thickness. Sex, IOP, and CCT showed no significant association with pRNFL thickness. These data may improve the interpretation of pRNFL data.

A Longitudinal Analysis of Peripapillary Choroidal Thinning in Healthy and Glaucoma Subjects

PURPOSE

To evaluate the rate of peripapillary choroidal thinning in glaucoma patients and healthy controls using spectral domain optical coherence tomography.

DESIGN

Cohort study.

METHODS

Participants from the multicenter African Descent and Glaucoma Evaluation Study and Diagnostic Innovations in Glaucoma Study were included. The San Diego Automated Segmentation Algorithm was used to automatically segment and measure peripapillary choroidal thickness (PCT) from circle scans centered on the optic nerve head. The rate of PCT thinning was calculated using mixed effects models.

RESULTS

Two hundred ninety-seven eyes with a median follow-up of 2.6 years were included. At baseline, the global mean PCT was significantly thinner in glaucoma patients than healthy control subjects (141.7 ± 66.3 μm vs 155.7 ± 64.8 μm, respectively; P < .001). However, when age was included in the model, this difference was no longer significant (P = .38). Both healthy controls and glaucoma patients had a significant decrease in mean (95% confidence interval) PCT change over time (-2.18 [-2.97 to -1.40 μm/year] and -1.88 [-3.08 to -0.67 μm/year], respectively) and mean PCT percent change over time (-3.32% [-4.36 to -2.27 μm/year] and -2.85% [-4.64 to -0.99 μm/year], respectively). No significant difference was found between healthy control subjects and glaucoma patients in the mean rate of PCT change (P = .28) or PCT percentage change over time (P = .23).

CONCLUSIONS

The rate of peripapillary choroidal thinning was not significantly different between healthy and glaucoma eyes during this relatively short follow-up period. Longer follow-up is needed to determine whether monitoring the rate of PCT change has a role in glaucoma management.

Primary Open-Angle Glaucoma Genetics in African Americans

PURPOSE OF REVIEW

Individuals of African descent are at highest risk for developing primary open-angle glaucoma (POAG), a devastating disease and major contributor of blindness worldwide. Currently, there is a large dearth of knowledge in this area despite a critical need for better understanding the underlying genetic and environmental factors afflicting this population. Here we highlight the current literature exploring the genetics of POAG in African Americans.

RECENT FINDINGS

Current studies have yet to replicate European POAG index variants (i.e. CDKN2B-AS1 and SIX1/SIX6) in African Americans or to definitely exclude that these loci contribute to risk in African descent populations. Recent studies have evaluated clinical features that may account for some differences in POAG risk between African Americans and European Americans.

SUMMARY

In summary, little headway has been made in elucidating the genetics of primary open-angle glaucoma in African Americans and other individuals of African descent.

Comparing the Rates of Retinal Nerve Fiber Layer and Ganglion Cell-Inner Plexiform Layer Loss in Healthy Eyes and in Glaucoma Eyes

PURPOSE

To compare the rates of circumpapillary retinal nerve fiber layer (RNFL) and macular retinal ganglion cell-inner plexiform layer (GCIPL) change over time in healthy and glaucoma eyes.

DESIGN

Cohort study.

METHODS

The rates of circumpapillary RNFL and macular GCIPL loss in 28 healthy subjects and 97 glaucoma subjects from the Diagnostic Innovations in Glaucoma Study (DIGS) were compared using mixed-effects models.

RESULTS

The median follow-up time and number of visits were 1.7 years and 6 visits and 3.2 years and 7 visits for healthy and glaucoma eyes, respectively. Significant rates of loss of both global circumpapillary RNFL and average macular GCIPL thickness were detectable in early and moderate glaucoma eyes; in severe glaucoma eyes, rates of average macular GCIPL loss were significant, but rates of global circumpapillary RNFL loss were not. In glaucoma eyes, mean rates of global circumpapillary RNFL thickness change (-0.98 μm/year [95% confidence interval (CI), -1.20 to -0.76]) and normalized global circumpapillary RNFL change (-1.7%/year [95% CI, -2.1 to -1.3]) were significantly faster than average macular GCIPL change (-0.57 μm/year [(95% CI, -0.73 to -0.41]) and normalized macular GCIPL change (-1.3%/year [95% CI, -1.7 to -0.9]). The rates of global and inferior RNFL change were weakly correlated with global and inferior macular GCIPL change (r ranges from 0.16 to 0.23, all P < .05).

CONCLUSIONS

In this cohort, the rate of circumpapillary RNFL thickness change was faster than macular GCIPL change for glaucoma eyes. Global circumpapillary RNFL thickness loss was detectable in early and moderate glaucoma, and average macular GCIPL thickness loss was detectable in early, moderate, and severe glaucoma, suggesting that structural changes can be detected in severe glaucoma.

[Differentiation of ocular hypertension]

The term ocular hypertension has been used for more than 30 years. It is defined as an elevated intraocular pressure above the statistical norm without detectable optic nerve head or visual field damage. The number of patients with ocular hypertension in Germany is estimated to be approximately 3-5 million. Increased intraocular pressure is a risk factor for conversion to primary open-angle glaucoma. Most patients with ocular hypertension (and no risk factors) can be followed on a regular basis without any treatment. Each visit should include measurement of intraocular pressure, optic nerve head examination with a slit lamp, imaging and perimetric examinations. Currently known risk factors are high intraocular pressure, higher age, myopia, a thin cornea and darkly pigmented skin. If risk factors are present, antiglaucomatous therapy is indicated.

A Longitudinal Study of Association between Adiposity Markers and Intraocular Pressure: The Kangbuk Samsung Health Study

Importance

Intraocular pressure (IOP) reduction or stabilization is the only proven method for glaucoma management. Identifying risk factors for IOP is crucial to understand the pathophysiology of glaucoma.

Objective

To examine the associations of change in body mass index (BMI), waist circumference, and percent fat mass with change in intraocular pressure (IOP) in a large sample of Korean adults.

Design, setting and participants

Cohort study of 274,064 young and middle age Korean adults with normal fundoscopic findings who attended annual or biennial health exams from January 1, 2002 to Feb 28, 2010 (577,981 screening visits).

Exposures

BMI, waist circumference, and percent fat mass.

Main Outcome Measure(s)

At each visit, IOP was measured in both eyes with automated noncontact tonometers.

Results

In multivariable-adjusted models, the average increase in IOP (95% confidence intervals) over time per interquartile increase in BMI (1.26 kg/m²), waist circumference (6.20 cm), and percent fat mass (3.40%) were 0.18 mmHg (0.17 to 0.19), 0.27 mmHg (0.26 to 0.29), and 0.10 mmHg (0.09 to 0.11), respectively (all P < 0.001). The association was stronger in men compared to women (P < 0.001) and it was only slightly attenuated after including diabetes and hypertension as potential mediators in the model.

Conclusions and Relevance

Increases in adiposity were significantly associated with an increase in IOP in a large cohort of Korean adults attending health screening visits, an association that was stronger for central obesity. Further research is needed to understand better the underlying mechanisms of this association, and to establish the role of weight gain in increasing IOP and the risk of glaucoma and its complications.

Rate and Pattern of Rim Area Loss in Healthy and Progressing Glaucoma Eyes

PURPOSE

To characterize the rate and pattern of age-related and glaucomatous neuroretinal rim area changes in subjects of African and European descent.

DESIGN

Prospective longitudinal study.

PARTICIPANTS

Two hundred ninety-six eyes of 157 healthy subjects (88 patients of African descent and 69 of European descent) and 73 progressing glaucoma eyes of 67 subjects (24 patients of African descent and 43 of European descent) from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study were included.

METHODS

Global and sectoral rim areas were measured using confocal laser scanning ophthalmoscopy. Masked stereophotograph review determined progression of glaucomatous optic disc damage. The rates of absolute rim area loss and percentage rim area loss in healthy and progressing glaucomatous eyes were compared using multivariate, nested, mixed-effects models.

MAIN OUTCOME MEASURES

Rate of rim area loss over time.

RESULTS

The median follow-up time was 5.0 years (interquartile range, 2.0-7.4 years) for healthy eyes and 8.3 years (interquartile range, 7.5-9.9 years) for progressing glaucoma eyes. The mean rate of global rim area loss was significantly faster in progressing glaucomatous eyes compared with healthy eyes for both rim area loss (-10.2×10(-3) vs. -2.8×10(-3) mm(2)/year, respectively; P < 0.001) and percentage rim area loss (-1.1% vs. -0.2%/year, respectively; P < 0.001), but considerable overlap existed between the 2 groups. Sixty-three percent of progressing glaucoma eyes had a rate of change faster than the fifth quantile of healthy eyes. For both healthy and progressing eyes, the pattern of rim area loss and percentage rim area loss were similar, tending to be fastest in the superior temporal and inferior temporal sectors. The rate of change was similar in progressing eyes of patients of African or European descent.

CONCLUSIONS

Compared with healthy eyes, the mean rate of global rim area loss was 3.7 times faster and the mean rate of global percentage rim area loss was 5.4 times faster in progressing glaucoma eyes. A reference database of healthy eyes can be used to help clinicians distinguish age-related rim area loss from rim area loss resulting from glaucoma.