Quantifying Factors Related to Severe Vision Loss in African Americans with Primary Open-Angle Glaucoma

Abstract

Purpose : Primary open-angle glaucoma (POAG) is particularly prevalent in individuals of African American descent; the phenotypic severity of POAG is greater, with the disease resulting in higher rates of blindness compared to other ethnic groups. The purpose of this study was to quantify the causes of severe vision loss (SVL) in a large African American cohort.

Methods : An electronic chart review was conducted on subjects enrolled in the Primary Open-Angle African American Glaucoma Genetics (POAAGG) study. Subjects with a diagnosis of POAG and SVL (defined as VA≤20/200) in one or both eyes were included. Demographic data, ocular and medical history, and cause(s) of SVL were assessed.

Results : Eighty-nine subjects, 50 female and 39 male, were identified. Average age was 74.4±11.8yrs (mean±SD). For 52 subjects (58%) SVL was due solely to POAG, and for 37 subjects (42%) SVL in one or both eyes was due to other causes including corneal scarring/edema, retinal detachment, central and branch vein occlusion, age-related macular degeneration, cystoid macular edema, optic neuropathy, neovascular glaucoma, and trauma (all developed after POAG diagnosis) (Table 1). Eyes with SVL from POAG had thinner corneas (512.8μm vs. 539.1μm; p=0.01) and larger cup-to-disc ratios (0.92 vs. 0.75; p=0.002) compared to eyes with SVL from other causes (Table 2). Subjects with SVL from POAG underwent more glaucoma surgeries (1.1 vs. 0.3; p<0.001) and similar numbers of laser procedures (0.7 vs. 0.6; p=0.68) (Table 1). While subjects with SVL from other causes trended towards a higher prevalence of systemic illnesses such as HTN, DM, TIA and CVA, differences were not significant (p=0.07-0.63) (Table 1). In those with SVL from POAG, the group with bilateral (N=15) versus unilateral SVL (N=37) trended towards older age (76.9 vs. 73.1yrs) and male gender (53 vs. 41%), and completed fewer visits since 2012 (58.7 vs. 64.1%). However, none of these differences were statistically significant (p>0.30), which may be due to the small sample sizes, but a lack of association cannot be disproven.

Conclusions : In an African American POAG cohort with SVL in one or both eyes, approximately half of subjects experienced SVL not related to POAG, often due to conditions associated with systemic illnesses. Diagnosis and treatment of ocular and systemic disease other than POAG is important in managing POAG patients.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.