Peripheral aberrations in adult hyperopes, emmetropes and myopes.

Abstract

To determine differences in peripheral aberrations in hyperopic, emmetropic and myopic groups. Cycloplegic peripheral aberrations for 5mm pupils were measured at 39 locations across 42°×32° of right eye visual fields with a COAS-HD Hartmann-Shack aberrometer in nine hyperopes (mean age 29±5years, spherical equivalent refraction M+1.47±0.58D), 20 emmetropes (28±7years, +0.06±0.36D) and 20 myopes (27±6years, -2.55±1.82D). Relative peripheral refraction error RPRE and 3rd-4th order Zernike coefficients were compared between the groups. Hyperopes and emmetropes had relative peripheral myopia across the visual field, with considerable nasal-temporal asymmetry for both groups and superior-inferior asymmetry for hyperopes. Myopes had minimal RPRE along the horizontal meridian, but myopic RPRE along the vertical meridian which was less than the other groups. There was little difference between groups in astigmatic components or higher-order Zernike coefficients, except for fourth-order spherical aberration which was more positive in hyperopes than in both emmetropes (mean difference ±95% CI=+0.05±0.05μm, p=0.03) and myopes (+0.07±0.04μm, p=0.003). Coma changed rapidly across the visual field with similar rates for all groups. Hyperopes and emmetropes had greater relative peripheral myopia than myopes. There was asymmetry in RPRE along the vertical meridian for hyperopes which was not present in the emmetropes, suggesting there may be asymmetries in peripheral eye length along the vertical meridian for the former. Higher-order aberrations were affected by field eccentricity, but refractive error affected only the spherical aberration coefficient, which was more positive for hyperopes than for other groups.