Differences in visual function and optic nerve structure between healthy eyes of blacks and whites

Abstract

Objective: To investigate differences in visual function, optic disc topography, and retinal nerve fiber layer (RNFL) thickness between healthy eyes of blacks and whites.

Methods: Visual function was assessed in healthy eyes of 50 blacks and 50 whites using standard automated perimetry, short-wavelength automated perimetry, and frequency doubling technology perimetry. Optic disc topography and RNFL thickness were measured using the Heidelberg Retina Tomograph and the optical coherence tomograph.

Results: Mean standard automated perimetry mean deviations were within the normal range for both groups. Blacks had worse mean deviation values than whites using frequency doubling technology perimetry (mean +/- SD, -1.8 +/- 3.2 dB vs -0.1 +/- 2.4 dB), blacks had larger optic disc areas than whites using the Heidelberg Retina Tomograph (mean +/- SD, 2.1 +/- 0.4 mm2 vs 1.7 +/- 0.4 mm2), the RNFL of blacks was thicker than that of whites by 16.91 microm superiorly and 10.10 microm inferiorly using optical coherence tomography, and blacks had slightly higher intraocular pressures than whites (mean +/- SD, 16.5 +/- 2.5 mm Hg vs 15.2 +/- 3.2 mm Hg) and thinner central corneas (mean +/- SD, 540.5 +/- 43.2 microm vs 560.9 +/- 35.5 microm). No racial differences were found in mean RNFL thickness, pattern standard deviation on all tests, or any of the short-wavelength automated perimetry variables.

Conclusions: Minimal racial differences in visual function were found, but race significantly affected optic disc topography and superior and inferior RNFL thickness measurements in healthy eyes. The racial differences observed for intraocular pressure could theoretically increase after correcting for central corneal thickness. Prospective studies are needed to further investigate these findings.