Racial differences in macular thickness in healthy eyes

The relationship between race and macular thickness remains unknown. This relationship may be important for early and accurate diagnosis of macular disease and glaucoma, and may also provide insight into disease mechanisms. In this study, we compared macular thickness in healthy eyes of black and white subjects using optical coherence tomography (Stratus OCT).

This study used a matched, cross-sectional design. Subjects underwent OCT macular thickness map scanning in each eye, four-field, 45-degree digital retinal imaging in each eye, and blood pressure measurement. Retinal images were evaluated for absence of posterior pole disorders, including macular and optic nerve disease. Retinal thickness was evaluated in the central fovea, and in rings placed at 1, 3, and 6 mm from fixation.

Compared with whites (n = 7), blacks (n = 7) had significantly thinner total foveal thickness (TFT, retinal thickness in the central 1 mm diameter area; OD: p < 0.03; OS: p < 0.02; OU average: p < 0.02), and thinner total macular thickness (TMT, retinal thickness in 6mm diameter area excluding central foveal thickness; OS: p < 0.02; OU average: p < 0.03). There was a trend for central foveal thickness (retinal thickness at fixation) to be thinner in blacks than whites (OD: p = 0.12; OS: p = 0.08). There was no significant difference in macular thickness between right and left eyes.

Retinal thickness as measured by Stratus OCT in the fovea and macula is significantly thinner in blacks compared with age-matched whites. Larger multiracial prospective studies are needed to confirm these results and to evaluate the need for race-specific normative values.