Abstract
Purpose::
The contributions of optical and neural factors to age-related losses in spatial vision are not fully understood. A number of investigations reported that optical factors alone limit contrast sensitivity, while others reported a neural origin for the loss. The use of adaptive optics (AO) makes it possible to measure and correct higher-order aberrations in the eye. Previous reports indicate that correcting higher-order aberrations through AO does improve the spatial limits of the visual system, but the effect of aging was not investigated. We propose to test the benefit of correcting high-order aberration on spatial vision across different age groups.
Methods::
Contrast sensitivity was measured for subjects ranging in age from 18 to 81 years with and without the correction for higher-order aberrations. The eye’s aberrations were measured using a Shack-Hartmann wavefront sensor (20x20 lenslet array) over a 7 mm pupil and then were corrected by a deformable mirror (DM) with 109 actuators. Without AO correction, trial lenses were used to correct lower-order aberrations, and the DM was flattened. Contrast sensitivity was measured monocularly using the method of adjustment for sinusoidal gratings at spatial frequencies of 0.55, 1.125, 2.25, 4.5, 9, and 18 cpd. Five threshold measurements were taken for each spatial frequency in random order.
Results::
Improvement in contrast sensitivity was found for all observers during AO correction. However, there was a spatial frequency dependent effect on the amount of improvement in contrast sensitivity during AO correction.
Conclusions::
The relative contribution of higher-order optical aberrations to age-related changes in spatial contrast sensitivity is spatial frequency dependent.
Keywords: aging: visual performance • contrast sensitivity • space and scene perception