Racial differences in the prevalence of age-related macular degeneration - The Salisbury Eye Evaluation (SEE) Project

Objective: To determine differences in the prevalence of age-related macular degeneration (AMD) and its fundus manifestations in a population-based sample of older black and white Americans. Design: Cross-sectional population-based study of 2520 participants of whom 1854 are white and 666 are black. Mean age was 73.5 years. Stereoscopic color fundus photographs were graded for presence, severity, and location of drusen, retinal pigment epithelium abnormalities, and choroidal neovascularization or disciform scarring. Results: Drusen at least 64 mu m in size were identified in 56% of black and white individuals within 3000 mu m of the foveal center, but drusen larger than 125 mu m were more common among white participants (16% white vs 11% black individuals). Drusen at least 250 mu m in size, confluent drusen, or a larger area (> 10%) occupied by drusen were each more common among white participants. White individuals were 3 times more likely to have focal hyperpigmentation than black individuals. Racial differences were most pronounced for features within the central 1500-mu m macular zone. Neovascular AMD was present in 1.7% of white participants and 1.1% of black participants (age-adjusted, P=.38), whereas geographic atrophy was more common in white than black individuals (1.8% vs 0.3%; age-adjusted, P=. 02). Conclusions: White persons are generally more likely than black persons to have medium or large drusen, focal pigment abnormalities, and advanced AMD. Racial differences were prominent for nonneovascular AMD features only when present in the central zone. These data suggest that black individuals may have a mechanism for protection in the central zone against these critical fundus features, which themselves convey high risk of progression to advanced AMD.