Peripheral Monochromatic Aberrations in Young Adult Caucasian and East Asian Eyes

SIGNIFICANCE: Myopia prevalence rates differ between racial groups. If the growth of the eye is sensitive to differences in optical input, the difference in spherical aberration between East Asian and Caucasian eyes found in this study may be important in understanding myopia development. PURPOSE: The aim of this study was to determine differences in peripheral wavefront aberrations between two racial groups. METHODS: Wavefront aberrations were measured using a COAS-HD aberrometer across the 42 x 32 degrees central visual field on 37 right eyes of young adults (18 Caucasians, 19 East Asians; mean age 21.5 +/- 2.4 years). The mean spherical equivalent refraction was -1.94 +/- 1.63 diopters (D) with a range of -5.87 to +0.16 D. Effect of race and visual field position on refractions, individual Zernike aberration coefficients up to the fourth order, higher-order root-mean-square aberration, and total root-mean-square aberration were assessed by repeated-measures analysis of covariance. RESULTS: Caucasians and East Asians had similar relative peripheral myopia across the visual field. All higher-order aberration coefficients were affected by visual field position. Race had no significant effect on any higher-order Zernike coefficient, but the difference in mean vertical coma coefficient C-3(-1) across the visual field (i.e., average of 38 field locations) approached significance, being less positive in Caucasians than in East Asians (P=.08). When correction was made for the Caucasian group being slightly less myopic than the East Asian group, spherical aberration coefficient C-4(0) was less positive in Caucasians than in East Asians by 0.04 mu m (P=.001). The rates of change of coma coefficients across the field were not affected by race. CONCLUSIONS: Caucasians and East Asians had similar relative peripheral myopia, but with less positive spherical aberration coefficient in Caucasians than in East Asians. It remains to be determined whether aberrations have a role in the difference of myopia prevalence rates in different countries.