Abstract
It has long been known that binocular visual performance is superior to monocular performance, a phenomenon commonly referred to as binocular summation. It is also well established that monocular vision can be improved significantly when ocular higher order aberrations are compensated. However, there have been limited studies to understand how binocular visual performance is affected by correcting the aberration in both eyes simultaneously. The purpose of this study was to investigate the binocular visual benefit after correcting ocular aberration and how the achieved improvement in retinal image quality affects binocular summation. A binocular adaptive optics (AO) system for vision testing was constructed with two identical monocular AO channels, one for each eye. Each monocular AO system consisted of a Shack-Hartmann wavefront sensor and a large-stroke deformable mirror (Mirao-52). Both monocular and binocular contrast sensitivity (4, 8, 16, 24 c/deg) was measured for a 6mm pupil under two conditions, (A) correction of defocus and astigmatism alone (B) correction of all aberrations. Vision testing was conducted while correcting aberrations in real-time to ensure reliable optical quality throughout the test. Three young cyclopleged normal subjects were employed for the study. Correcting aberrations in both eyes simultaneously (condition B) led to an average improvement of binocular contrast sensitivity by a factor of 2.0, 2.0, 2.7 and 3.0 at 4, 8, 16 and 24 c /deg respectively, compared to correction of defocus and astigmatism alone (condition A). Average binocular summation factor, defined as the ratio of binocular to monocular contrast sensitivity, was reduced in condition (B) compared to condition (A) by 38%, 35%, 3% and 6% at 4, 8, 16 and 24 c /deg respectively. The reduction in the summation factor was statistically significant at 4 and 8 c/deg (p=0.001). In summary, significant binocular visual benefit was obtained after simultaneous correction of aberrations in both eyes. However, binocular summation factor may differ between corrected and native retinal image quality.