Estimating visual acuity from a single wavefront measurement

Wavefront metrics such as root mean squared error provide excellent descriptions of optical quality but the connection to visual performance is not directly interpretable from the wavefront alone. Converting to visual acuity (VA) would provide a more accessible assessment of the effect of ocular wavefront. In this study, multiple measurements of wavefront and pupil diameter were acquired at 1 cd/m2 using the iDesign 1.3 (Johnson and Johnson Surgical Vision) in 552 eyes of 293 subjects. Uncorrected (UC) and best corrected (BC) VA were measured at 4m for each eye at 100 cd/m2 . VA was estimated using a neural contrast sensitivity function (NCSF) weighted modulation transfer function (MTF). To estimate BCVA, sphere and astigmatism terms were nulled. For each subject, classification was performed using random forest considering estimated VA, age, measured pupil diameter, manifest refraction spherical equivalent, manifest refraction cylinder and gender. Across all measurements, predicted differed from measured UCVA by -0.11 and BCVA by +1.6 (-10logMAR). The NCSF-based model predicts population mean VA to within approximately 2-lines but cannot predict an individual’s VA well, supporting the notion that other factors need to be considered to obtain more accurate estimates of VA. Classification with the random forest approach improved the accuracy of estimates of an individual subject’s VA; approximately 95% of the estimates match the measured VA.