Metrics of optical quality derived from wave aberrations predict visual performance

TLDR

Wavefront‑guided refractive surgery has reduced residual RMS wavefront error to ~0.25 μm, yet variations in its distribution can alter visual acuity by up to two lines, highlighting the need for single‑value metrics beyond RMS. This study examines how 31 single‑value optical quality metrics correlate with high‑contrast visual acuity when RMS wavefront error is 0.25 μm over a 6‑mm pupil. We evaluate these metrics across 34 conditions, measuring their values and corresponding visual acuity to assess predictive relationships. The visual Strehl ratio explains 81 % of the variance in high‑contrast logMAR acuity, making it the most effective metric.

Abstract

Wavefront-guided refractive surgery and custom optical corrections have reduced the residual root mean squared (RMS) wavefront error in the eye to relatively low levels (typically on the order of 0.25 microm or less over a 6-mm pupil, a dioptric equivalent of 0.19 D). It has been shown that experimental variation of the distribution of 0.25 microm of wavefront error across the pupil can cause variation in visual acuity of two lines on a standard logMAR acuity chart. This result demonstrates the need for single-value metrics other than RMS wavefront error to quantify the effects of low levels of aberration on acuity. In this work, we present the correlation of 31 single-value metrics of optical quality to high-contrast visual acuity for 34 conditions where the RMS wavefront error was equal to 0.25 microm over a 6-mm pupil. The best metric, called the visual Strehl ratio, accounts for 81% of the variance in high-contrast logMAR acuity.