Primary Open-Angle Glaucoma Genetics in African Americans

Exploring Associations between Race/Ethnicity and Glaucoma Prevalence in a Multicenter Brazilian Study: The ELSA-Brasil

Purpose

Previous research indicates a higher prevalence of glaucoma in Black individuals of African descent. However, the association between race and glaucoma in Brazil's multiracial population remains underexplored. This study examines this association and seeks to identify preventable factors potentially influencing prevalence differences among racial groups in Brazil, should such difference be found.

Methods

Employing a cross-sectional design, data were analyzed from 10,696 participants in the multicenter Brazilian Longitudinal Study of Adult Health (2008-2010) who self-identified their race as White, Black, mixed race (pardo), Asian, or Indigenous and completed an ophthalmological questionnaire including their self-reported glaucoma status (yes or no). Poisson regression was used to estimate prevalence ratios (PRs) with robust SEs and adjustments for sociodemographic characteristics and the presence of diabetes, hypertension, and obesity.

Results

The prevalence of glaucoma was 5.8% in Black (86/1483), 3.8% in mixed race (101/2688), 3.8% in indigenous (4/106), 3.5% in Asian (10/288), and 2.4% in White (145/6131) populations. Compared with Whites, Blacks and mixed-race individuals were younger. Age-adjusted prevalence was 175% higher in Black individuals (PR=2.75, 95% confidence interval [CI]: 2.12, 3.56) and 85% higher in mixed-race individuals (PR=1.85, 95% CI: 1.44, 2.36) compared with Whites. The strength of these associations was reduced in models including the comorbidities of obesity, hypertension, and diabetes, which are more prevalent in Black and mixed-race individuals.

Conclusions

Our results reveal a higher prevalence of self-reported glaucoma in non-White groups, especially among Black and mixed-race individuals. Although causality cannot be conclusively established, our data suggest that the increased prevalence of glaucoma in these groups, compared with their White peers, is partially influenced by preventable health conditions.

Prevalence of Glaucoma Among US Adults in 2022

Importance

Glaucoma is the leading cause of irreversible blindness worldwide and, in the US, disproportionately affects people from racial and ethnic minority groups. Glaucoma prevalence has not been estimated for the US in more than a decade, and state- and county-level estimates are not available.

Objective

To estimate glaucoma and vision-affecting glaucoma prevalence by demographic factors and US state and county for the Centers for Disease Control and Prevention's Vision and Eye Health Surveillance System (VEHSS).

Data Sources

This meta-analysis used data from the National Health and Nutrition Examination Survey (2005-2008), Medicare fee-for-service claims (2019), IBM MarketScan commercial insurance claims (2016), population-based studies of eye disease (1985-2003), and 2022 population estimates from the US Census Bureau.

Study Selection

PubMed was searched for population-based studies of glaucoma prevalence published between 1991 and 2016.

Data Extraction and Synthesis

Bayesian meta-regression methods were used to estimate the prevalence of glaucoma and vision-affecting glaucoma stratified by age, undifferentiated sex/gender (a measure that captures an unclear mix of aspects of sex and or gender), race and ethnicity, and US county and state.

Main Outcomes and Measures

Prevalence of any type of glaucoma (open or closed angle) among people 18 years or older and vision-affecting glaucoma, defined as glaucoma and a visual field abnormality.

Results

For 2022, an estimated 4.22 million people (95% uncertainty interval [UI], 3.46 million to 5.23 million) in the US were living with glaucoma, with a prevalence of 1.62% (UI, 1.33%-2.00%) among people 18 years or older and 2.56% (UI, 2.10%-3.16%) among people 40 years or older. An estimated 1.49 million people (UI, 1.17 million to 1.90 million) were living with vision-affecting glaucoma, with a prevalence of 0.57% (UI, 0.45%-0.73%) among people 18 years or older and 0.91% (UI, 0.71%-1.16%) among people 40 years or older. Prevalence of glaucoma among people 18 years or older ranged from 1.11% (UI, 0.89%-1.40%) in Utah to 1.95% (UI, 1.57%-2.39%) in Mississippi. Black adults had a prevalence of 3.15% (UI, 2.32%-4.09%) compared with 1.42% (UI, 1.10%-1.85%) among White adults; adults in the Hispanic and all other racial and ethnic categories combined had a prevalence of 1.56% (UI, 1.13%-2.06%).

Conclusions and Relevance

This meta-analysis found that an estimated 2.56% of people 40 years or older have glaucoma, slightly more than estimated by previous studies. Black individuals are disproportionately affected. Prevalence estimates at the state and county level can help guide public health planning.

Unfulfilled Needs in the Detection, Diagnosis, Monitoring, Treatment, and Understanding of Glaucoma in Blacks Globally

Glaucoma is an ophthalmic disorder that affects a significant number of Blacks globally. A leading cause of this condition is an age-related enlargement of the lens and increased intraocular pressure. Although Blacks are affected by glaucoma at a higher rate than their Caucasian counterparts, there remains a lack of emphasis placed on the detection, diagnosis, monitoring, and treatment of glaucoma in this population. Education regarding glaucoma in the African and African American populations is essential to reducing rates of glaucoma-related visual impairment and improving treatment success. In this article, we highlight specific issues and limitations to the management of glaucoma, which affects Blacks at a higher rate. In addition, we also review the backgrounds of Blacks globally and examine historical events that have contributed to financial inequality and wealth/health disparities affecting glaucoma management. Lastly, we suggest reparations and solutions that health care professionals can use to improve glaucoma screening and management.

National Utilization of Glaucoma Laser and Surgical Management in Medicare Beneficiaries: Disparities and Accessibility

PRCIS

In this population-based, cross-sectional study of Medicare beneficiaries, there were lower odds of national glaucoma surgery among ages older than 85, female sex, Hispanic ethnicity, and diabetic comorbidity. Glaucoma surgery rates were independent of ophthalmologist distribution.

PURPOSE

With an increasing prevalence of glaucoma in the United States, it is crucial to elucidate surgical procedure accessibility to deliver quality care. The objective of this study was to estimate national access to surgical glaucoma care by (1) comparing diagnostic and surgical management Medicare insurance claims followed by (2) correlating Medicare treatment claims with regional ophthalmologist availability.

PATIENTS AND METHODS

This cross-sectional study included Medicare claims from the 2017 Vision and Eye Health Surveillance System and workforce data from the 2017 Area Health Resource Files, both public domain databases. A total of 25,443,400 beneficiaries fully enrolled in Medicare Part B Fee-for-Service with glaucoma diagnosis claims were included. Rates of US MD ophthalmologists were determined by Area Health Resource Files distribution densities. Surgical glaucoma management rates included Medicare service utilization claims for drain, laser, and incisional glaucoma surgery.

RESULTS

While Black, non-Hispanic Americans had the highest prevalence of glaucoma, Hispanic beneficiaries had the highest odds of surgery. Older age (85+ vs. 65-84 y; Odds Ratio [OR]=0.864; 95% Confidence Interval [CI], 0.854-0.874), female sex (OR=0.923; 95% CI, 0.914-0.932), and having diabetes (OR=0.944; 95% CI, 0.936-0.953) was associated with lower odds of having a surgical glaucoma intervention. Glaucoma surgery rates were not associated with ophthalmologist density by state.

CONCLUSIONS

Glaucoma surgery utilization differences by age, sex, race/ethnicity, and systemic comorbidities warrant further investigation. Glaucoma surgery rates are independent of ophthalmologist distribution by state.

Identifying, Understanding, and Addressing Disparities in Glaucoma Care in the United States

Glaucoma is the leading cause of irreversible blindness worldwide, currently affecting around 80 million people. Glaucoma prevalence is rapidly rising in the United States due to an aging population. Despite recent advances in the diagnosis and treatment of glaucoma, significant disparities persist in disease detection, management, and outcomes among the diverse patient populations of the United States. Research on disparities is critical to identifying, understanding, and addressing societal and healthcare inequalities. Disparities research is especially important and impactful in the context of irreversible diseases such as glaucoma, where earlier detection and intervention are the primary approach to improving patient outcomes. In this article, we first review recent studies identifying disparities in glaucoma care that affect patient populations based on race, age, and gender. We then review studies elucidating and furthering our understanding of modifiable factors that contribute to these inequities, including socioeconomic status (particularly age and education), insurance product, and geographic region. Finally, we present work proposing potential strategies addressing disparities in glaucoma care, including teleophthalmology and artificial intelligence. We also discuss the presence of non-modifiable factors that contribute to differences in glaucoma burden and can confound the detection of glaucoma disparities.

Translational Relevance

By recognizing underlying causes and proposing potential solutions, healthcare providers, policymakers, and other stakeholders can work collaboratively to reduce the burden of glaucoma and improve visual health and clinical outcomes in vulnerable patient populations.

Myocilin misfolding and glaucoma: A 20-year update

Mutations in the gene MYOC account for approximately 5% of cases of primary open angle glaucoma (POAG). MYOC encodes for the protein myocilin, a multimeric secreted glycoprotein composed of N-terminal coiled-coil (CC) and leucine zipper (LZ) domains that are connected via a disordered linker to a 30 kDa olfactomedin (OLF) domain. More than 90% of glaucoma-causing mutations are localized to the OLF domain. While myocilin is expressed in numerous tissues, mutant myocilin is only associated with disease in the anterior segment of the eye, in the trabecular meshwork. The prevailing pathogenic mechanism involves a gain of toxic function whereby mutant myocilin aggregates intracellularly instead of being secreted, which causes cell stress and an early timeline for TM cell death, elevated intraocular pressure, and subsequent glaucoma-associated retinal degeneration. In this review, we focus on the work our lab has conducted over the past ∼15 years to enhance our molecular understanding of myocilin-associated glaucoma, which includes details of the molecular structure and the nature of the aggregates formed by mutant myocilin. We conclude by discussing open questions, such as predicting phenotype from genotype alone, the elusive native function of myocilin, and translational directions enabled by our work.

Glaucoma and Systemic Disease

Glaucoma is the leading cause of irreversible blindness in the world. Due to its potential to cause permanent vision loss, it is important to understand how systemic conditions and their respective treatments can be associated with or increase the risk for developing glaucoma. In this review, we examined the literature for up-to-date discussions and provided commentary on glaucoma, its pathophysiology, and associated risk factors. We discuss systemic diseases and the impact, risk, and mechanism for developing glaucoma, including pharmacologically induced glaucoma; inflammatory and auto-immune conditions; infectious, dermatologic, cardiovascular, pulmonary, renal, urologic, neurologic, psychiatric and systemic malignancies: intraocular tumors; as well as pediatric, and genetic conditions. The goal of our discussion of systemic conditions including their commonality, mechanisms, treatments, and associations with developing glaucoma is to emphasize the importance of ocular examinations and follow-up with the multidisciplinary teams involved in the care of each patient to prevent unnecessary vision-loss.

Evolutionary Landscape of SOX Genes to Inform Genotype-to-Phenotype Relationships

The SOX transcription factor family is pivotal in controlling aspects of development. To identify genotype-phenotype relationships of SOX proteins, we performed a non-biased study of SOX using 1890 open-reading frame and 6667 amino acid sequences in combination with structural dynamics to interpret 3999 gnomAD, 485 ClinVar, 1174 Geno2MP, and 4313 COSMIC human variants. We identified, within the HMG (High Mobility Group)- box, twenty-seven amino acids with changes in multiple SOX proteins annotated to clinical pathologies. These sites were screened through Geno2MP medical phenotypes, revealing novel SOX15 R104G associated with musculature abnormality and SOX8 R159G with intellectual disability. Within gnomAD, SOX18 E137K (rs201931544), found within the HMG box of ~0.8% of Latinx individuals, is associated with seizures and neurological complications, potentially through blood-brain barrier alterations. A total of 56 highly conserved variants were found at sites outside the HMG-box, including several within the SOX2 HMG-box-flanking region with neurological associations, several in the SOX9 dimerization region associated with Campomelic Dysplasia, SOX14 K88R (rs199932938) flanking the HMG box associated with cardiovascular complications within European populations, and SOX7 A379V (rs143587868) within an SOXF conserved far C-terminal domain heterozygous in 0.716% of African individuals with associated eye phenotypes. This SOX data compilation builds a robust genotype-to-phenotype association for a gene family through more robust ortholog data integration.

Diversity in Polygenic Risk of Primary Open-Angle Glaucoma

Glaucoma is the leading cause of irreversible blindness worldwide. Primary open-angle glaucoma (POAG), the most common glaucoma subtype, is more prevalent and severe in individuals of African ancestry. Unfortunately, this ancestral group has been historically under-represented among genetic studies of POAG. Moreover, both genetic and polygenic risk scores (GRS, PRS) that are typically based on genetic data from European-descent populations are not transferable to individuals without a majority of European ancestry. Given the aspirations of leveraging genetic information for precision medicine, GRS and PRS demonstrate clinical potential but fall short, in part due to the lack of diversity in these studies. Prioritizing diversity in the discovery of risk variants will improve the performance and utility of GRS and PRS-derived risk estimation for disease stratification, which could bring about earlier POAG intervention and treatment for a disease that often goes undetected until significant damage has occurred.

Social determinants associated with loss of an eye in the United States using the All of Us nationwide database

PURPOSE

To identify common factors associated with the loss of an eye using the NIH All of Us database.

METHODS

In this case-controlled study, we extracted electronic health record and socio-demographic data for 231 cases of eye loss from All of Us enrollment sites. Controls (N = 924) matched the demographic characteristics of the 2020 United States Census. Bivariate analyses and multivariable logistic regression identified variables significantly associated with increased odds of eye loss.

OUTCOME MEASURES

Medical and social determinants associated with increased odds of losing an eye.

RESULTS

Among cases, the average age (standard deviation) was 60.1 (14.4) years. The majority (125, 54.1%) were male. 87 (37.7%) identified as African American, and 49 (21.2%) identified as Hispanic or Latino. Loss of eye was more likely in those with ocular tumor (odds ratio [OR] 421.73, 25 95% confidence interval [CI] 129.81-1959.80, p < .001), trauma (OR 13.38, 95% CI 6.64-27.43, p < .001), infection (OR 11.46, 95% CI 4.11-32.26, p = .001) or glaucoma (OR 8.33, 95% CI 4.43- 15.81, p < .001). African American (OR 2.39, 95% CI 1.39-4.09, p = .002) and Hispanic or Latino (OR 1.80, 95% CI 1.01-3.15, p = .04) participants were disproportionately affected.

CONCLUSIONS

Racial and ethnic disparities exist among those with loss of an eye from underlying conditions. Addressing health inequities may mitigate the risk of this morbid outcome.

Glaucoma Genetic Risk Scores in the Million Veteran Program

PURPOSE

Primary open-angle glaucoma (POAG) is a degenerative eye disease for which early treatment is critical to mitigate visual impairment and irreversible blindness. POAG-associated loci individually confer incremental risk. Genetic risk score(s) (GRS) could enable POAG risk stratification. Despite significantly higher POAG burden among individuals of African ancestry (AFR), GRS are limited in this population. A recent large-scale, multi-ancestry meta-analysis identified 127 POAG-associated loci and calculated cross-ancestry and ancestry-specific effect estimates, including in European ancestry (EUR) and AFR individuals. We assessed the utility of the 127-variant GRS for POAG risk stratification in EUR and AFR Veterans in the Million Veteran Program (MVP). We also explored the association between GRS and documented invasive glaucoma surgery (IGS).

DESIGN

Cross-sectional study.

PARTICIPANTS

MVP Veterans with imputed genetic data, including 5830 POAG cases (445 with IGS documented in the electronic health record) and 64 476 controls.

METHODS

We tested unweighted and weighted GRS of 127 published risk variants in EUR (3382 cases and 58 811 controls) and AFR (2448 cases and 5665 controls) Veterans in the MVP. Weighted GRS were calculated using effect estimates from the most recently published report of cross-ancestry and ancestry-specific meta-analyses. We also evaluated GRS in POAG cases with documented IGS.

MAIN OUTCOME MEASURES

Performance of 127-variant GRS in EUR and AFR Veterans for POAG risk stratification and association with documented IGS.

RESULTS

GRS were significantly associated with POAG (P < 5 × 10-5) in both groups; a higher proportion of EUR compared with AFR were consistently categorized in the top GRS decile (21.9%-23.6% and 12.9%-14.5%, respectively). Only GRS weighted by ancestry-specific effect estimates were associated with IGS documentation in AFR cases; all GRS types were associated with IGS in EUR cases.

CONCLUSIONS

Varied performance of the GRS for POAG risk stratification and documented IGS association in EUR and AFR Veterans highlights (1) the complex risk architecture of POAG, (2) the importance of diverse representation in genomics studies that inform GRS construction and evaluation, and (3) the necessity of expanding diverse POAG-related genomic data so that GRS can equitably aid in screening individuals at high risk of POAG and who may require more aggressive treatment.

Clinical Characteristics and Stage at Presentation of Glaucoma Patients in Sub-Saharan Africa

PURPOSE

To explore regional variations in the presentation of newly diagnosed glaucoma in Sub Saharan Africa (SSA).

METHODOLOGY

This was a multi-centre, cross-sectional study in which newly diagnosed, consecutive, glaucoma patients aged ≥18 years were recruited from 27 eye clinics in 10 countries throughout SSA. Demographic and ophthalmic examination data were collected. Glaucoma severity was based on optic nerve head and visual field assessment. Statistical analyses were performed using STATA version 14.0.

RESULTS

Among 1214 enrolled patients with newly diagnosed glaucoma from Western, Eastern and Southern Africa, the overall mean (standard deviation) age was 59.9 (17.1) years. More than half of all patients (716/1178; 60.8%) presented with severe glaucoma in the worse eye, and one third (36.9%) had severe glaucoma in both eyes. Primary open-angle glaucoma was the commonest form of glaucoma in all regions (77.4%). A family history of blindness (260/1204, 21.6%) was common. Patients from Western Africa had lower mean presenting IOP (26.4 [11.1] mmHg, P <0.001), but had worse glaucoma in the better eye based on mean cup-disc ratio (0.8; P <0.001) and mean visual field mean deviation [10.4 (8.4)] dB, P =0.016) compared to other regions. Exfoliation glaucoma was more common in Eastern Africa (30/170=17.7%, P <0.001) compared to other regions.

CONCLUSION

The initial presentation of glaucoma varies meaningfully across SSA. A comprehensive strategy with regional customization based on local differences is needed to reduce glaucoma blindness in SSA.

Racial and Ethnic Disparities in Primary Open-Angle Glaucoma Clinical Trials: A Systematic Review and Meta-analysis

IMPORTANCE

The disease burden for primary open-angle glaucoma (POAG) is highest among racial/ethnic minority groups, particularly Black individuals. The prevalence of POAG worldwide is projected to increase from 52.7 million in 2020 to 79.8 million in 2040, a 51.4% increase attributed mainly to Asian and African individuals. Given this increase, key stakeholders need to pay particular attention to creating a diverse study population in POAG clinical trials.

OBJECTIVE

To assess the prevalence of racial/ethnic minorities in POAG clinical research trials compared with White individuals.

DATA SOURCES

This meta-analysis consisted of publicly available POAG clinical trials using ClinicalTrials.gov, PubMed, and Drugs@FDA from 1994 to 2019.

STUDY SELECTION

Randomized clinical trials that reported on interventions for POAG and included demographic subgroups including sex and race/ethnicity.

DATA EXTRACTION AND SYNTHESIS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 2 independent reviewers extracted study-level data for a random-effects meta-analysis. A third person served as the tiebreaker on study selection. Microsoft Excel 2016 (Microsoft Corporation) and SAS, version 9.4 (SAS Institute) were used for data collection and analyses.

MAIN OUTCOMES AND MEASURES

The primary outcomes were the prevalence of each demographic subgroup (White, Black, Hispanic/Latino, other race/ethnicity groups, and female or male) in each trial according to the trial start year, study region, and study sponsor. Participation rates are expressed as percentages.

RESULTS

A total of 105 clinical trials were included in the meta-analysis, including 33 428 POAG clinical trial participants (18 404 women [55.1%]). Overall, 70.7% were White patients, 16.8% were Black patients, 3.4% were Hispanic/Latino patients, and 9.1% were individuals of other races/ethnicities, including Asian, Native Hawaiian or Pacific Islander, American Indian or Alaska Native, and unreported as defined by the US Census. The mean (SD) numbers of participants by race/ethnicity were 236.5 (208.2) for White, 58.4 (70.0) for Black, 29.9 (71.1) for Hispanic/Latino, and 31.1 (94.3) for other race/ethnicity. According to the test for heterogeneity using the Cochrane Risk of Bias tool, the I2 statistic was 98%, indicating high heterogeneity of outcomes in the included trials. A multiple linear regression analysis was performed to assess any trend and significance between participation by Black individuals and the year the study started, the region in which the study took place, and the study sponsor. There was no significant increase of Black participant enrollment from 1994 to 2019 (r2 = 0.11; P = .17) and no significant association between Black participant enrollment and clinical trial region (r2 = 0.16; P = .50), but there was a significant association between Black participant enrollment and study sponsor (r2 = 0.94; P = .03).

CONCLUSIONS AND RELEVANCE

This meta-analysis found that compared with White individuals, individuals from racial/ethnic minority groups had a very low participation rate in POAG clinical trials despite having a higher prevalence among the disease population. Despite measures to increase clinical trial diversity, there has not been a significant increase in clinical trial participation among Black individuals, the group most affected by this disease; this disparity in POAG clinical trial representation can raise questions about the true safety and efficacy of approved medical interventions for this disease and should prompt further research on how to increase POAG clinical trial diversity.

Epidemiology of Glaucoma: The Past, Present, and Predictions for the Future

Glaucoma is a multifactorial optic degenerative neuropathy characterized by the loss of retinal ganglion cells. It is a combination of vascular, genetic, anatomical, and immune factors. Glaucoma poses a significant public health concern as it is the second leading cause of blindness after cataracts, and this blindness is usually irreversible. It is estimated that 57.5 million people worldwide are affected by primary open-angle glaucoma (POAG). People over 60 years of age, family members of those already diagnosed with glaucoma, steroid users, diabetics, as well as those with high myopia, hypertension, central cornea thickness of <5 mm, and eye injury are at an increased risk of glaucoma. By 2020, it is expected that approximately 76 million people will suffer from glaucoma with that number estimated to reach 111.8 million by 2040. In this article, we perform an extensive literature review focusing on the epidemiology of glaucoma and try to determine the number of people affected; we categorize them by sex, location, and level of income. Furthermore, we strive to estimate the future projection of the disease in the next 20 years (2040) while determining the disease burden, including the cost involved in treating and preventing the disease and the disease and disability projection of glaucoma.