Abstract
Abstract: :
Purpose:The purpose of this study is to investigate the relationship between accommodative lag and wavefront aberrations in accommodated eyes of myopes and emmetropes. Methods: Accommodation, induced either by a near target (0.33m) or by a negative lens (–3.0D) with a distant target (4.0m), was measured using a Canon R–1 autorefractor in 27 young myopic (spherical equivalent ranged from –6.25 to –0.50, mean = –2.38D) and 57 young emmetropic subjects (spherical equivalent ranged from –0.25 to 0.75, mean = 0.24D). Wavefront aberrations were measured using a psychophysical ray–tracing technique. Only the right eye was tested for all subjects. The accommodative lags (accommodative stimulus – accommodative response) and Strehl ratios (derived from the wavefront aberrations) were compared between the myopic and emmetropic groups. Results: Larger accommodative lags were found for the myopes than the emmetropes in both the lens–induced (1.85D vs. 0.77D, t=4.95, p<0.001) and distance–induced conditions (0.57D vs. 0.31D, t=1.77, p<0.05). The mean Strehl ratio was significantly smaller (t =1.95, p<0.05) in the myopes than the emmetropes (0.069 vs. 0.084). For the myopic group, the accommodative lag was significantly correlated with the Strehl ratio (r = –0.50, p<0.01) in the lens–induced condition. However, neither the correlation between accommodative lag and refractive error nor the correlation between the Strehl ratio and refractive error was found to be significant for myopes. No significant correlations were found for emmetropes. Conclusion: Larger accommodative lags in myopic eyes are associated with elevated levels of wavefront aberrations.