Calculations and measurements of the visual benefit of correcting the higher-order aberrations using adaptive optics technology

Abstract

Purpose: Our goal was to examine the accuracy of metrics, calculated using a numerical eye model including the measurement of the monochromatic aberrations of the eye, to predict the contrast sensitivity (CS) and visual acuity (VA) visual benefits (VB) of correcting higher-order aberrations (HO). Methods: We measured, on the right eyes of 25 subjects (10 myopes and 15 emmetropes) aged 21 to 56 years, the 16 c/deg CS and high-contrast VA in two conditions of aberration corrections: (i) when correcting only the defocus and astigmatism terms and (ii) when dynamically correcting all the monochromatic aberration terms up to the 5th order. The measured VB was defined as the ratio of the performances between these two conditions of aberration corrections. Results: We measured a VB of 1.25 and 1.64 respectively in term of VA and CS. We did not find any influence of age on the VB and no statistical significant difference between the myopic and emmetropic group. The contrast sensitivity VB was well correlated (r2=0.79) with the ratio of the modulation transfer functions calculated at 16 c/deg in both conditions of aberrations corrections (i.e. MTF16c/deg HO/MTF16c/deg SC). The levels of correlation between various metrics and measured visual acuity VB were lower (r2=0.30 in the better case), however the averaged VB was correctly predicted by the ratio of the intersections between the MTF and a typically neural contrast threshold function. Conclusions: Metrics based on wave aberration measurements are able to predict the impact of monochromatic aberrations on CS. © 2008 Spanish Council of Optometry.