Our findings suggests that retinal shape is not different in eyes of anisometropes than in eyes of isometropes with the same refractions.
We investigated a) inter-eye differences in relative peripheral eye lengths (RPEL) between isometropes and anisometropes, and b) if the retinal shape is different between isometropic and anisometropic eyes with the same central refraction.
Central and peripheral eye lengths were determined along the horizontal meridian in 10° intervals out to ±30°, using a non-contact biometer in 28 isometropes and 16 anisometropes. Retinal coordinates were estimated using these eye lengths and ray tracing. Retinal shape was determined in terms of vertex radius of curvature (Rv), asphericity (Q), and equivalent radius of curvature (REq). Linear regression was determined for the REq as functions of central refraction in a subset of isometropic and anisometropic eyes having the same refraction.
The differences in RPEL between the two eyes of anisometropes were significantly greater than for isometropes at ±30° eccentricities. Higher myopic eyes of anisometropes had smaller Rv, more negative Q and smaller REq than the lower myopic eyes for both isometropes and anisometropes (Rv mean ± SEM: 9.8 ± 0.5 mm vs. 11.7 ± 0.4 mm, P = .002; Q: –1.1 ± 0.2 vs. –0.5 ± 0.2, P = .03; REq: 11.5 ± 0.3 mm vs. 12.4 ± 0.2 mm, P = .01). Intercepts and slopes of the linear regressions of REq in anisometropes and their isometropic counterparts with the same refraction were not significantly different from each other (P > .05).
Higher myopic eyes of anisometropes had similar retina shapes along the horizontal meridian as isometropic eyes with the same refraction.