Compensation effect between corneal and internal aberrations during a computer task

Abstract

This study aimed to investigate if the compensation effect that exists between cornea and the internal optics of the eye changes with a computer near vision task.Nineteen emmetropic students of University of Minho (19 eyes) with a mean age of 22.7 years old (range from 19 to 25 years old) performed a computer reading task (with an accommodative demand of 2.50 D) for 30 minutes. Ocular and corneal aberrations were measured immediately before and after the task using the Visionix VX 120 (VisionixLuneau,Chartes,France) equipment. The results were evaluated for a 5 mm pupil diameter.The compensation factor was computed from the RMS values of the low order aberrations (LOA) 3rd order to 6th order aberrations, coma, spherical aberrations (SA) and high order aberrations (HOA).Results showed a decrease in the compensation factor for LOA, third order aberration and coma but others suffer no changes. It seems that there was an interaction between corneal and internal aberrations during the computer near vision. The visual system seems to adapt to compensate the changes provoked by the task, leading to a diminution of total ocular aberrations, allowing a reduction of ocular optical quality with the task less intensified.