Racial variability of glaucoma risk factors between African Caribbeans and Caucasians in a Canadian urban screening population

Background: The significance of race in the development and progression of glaucoma remains controversial, although in most cases the evidence shows greater prevalence and progression of the disease in African American populations. The purpose of this study was to determine the impact of the African Caribbean race on the variability of risk factors for glaucoma in an urban Canadian screening population. Study Design: Population-based, cross-sectional study. Participants: Participants with high risk for development of open-angle glaucoma. Methods: Participants underwent confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomograph), frequency-doubling technology (FDT) perimetry, and complete ophthalmic examination during a high-risk glaucoma screening clinic. Statistical analysis was performed comparing the data gathered from these tests in the different racial groups. Student's t tests as well as Pearson's chi(2) tests were done. Results: Racial breakdown included 64 African Caribbeans (22%) and 224 Caucasians (78%). Racial groups had similar female/male ratios, but Caucasians were significantly older (66 [SD 12] years) than African Caribbeans (56 [SD 12] years) (p = 0.001). African Caribbeans had significantly higher intraocular pressure (IOP) (p < 0.001); thinner central corneal thickness (CCT) (p < 0.001); greater cup/disc ratio (p = 0.016), disc area (p < 0.001), cup area (p = 0.002), and cup/disc area ratio (p = 0.009); and smaller rim/disc area ratio (p = 0.009). The latter optic disc parameter differences were not statistically different when corrected for disc area differences. Conclusions: In this study, African Caribbeans in a Canadian urban setting were associated with increased risk factors for open-angle glaucoma development, including higher IOP and thinner CCT The larger cup/disc and cup/disc area ratios of the African Caribbean group were directly correlated to disc area differences between the 2 groups.