Age-related alterations in retinal function.

Age-related visual deficits that occur in the absence of recognized visual disease are frequently observed. Many of the optical factors contributing to these deficits have been delineated, but the contributing neurophysiological alterations have not been clearly defined. This investigation examined age-related variations in the retinal and cortical processing of visual information. Pattern-specific retinal potentials (pattern electroretinogram or PERG in this series) and cortical potentials (VECPs) were recorded from nine young visual normals (20-30 years) and nine healthy elderly individuals (70-80 years). All subjects had best corrected visual acuity of 20/30 or better. Checkerboard patterns (7.5-60 min. checks) were modulated in a counterphase mode (2.0 and 7.5 rps). PERGs and VECPs were simultaneously recorded. Significant age-related alterations in waveform amplitude and latency were observed for both biopotentials. The VECP alterations were largely the result of the reduction in retinal illumination associated with senile miosis, but this factor could not account for most of the observed PERG alterations. These results suggest that neurophysiological changes in the retina may underlie some of the visual deficits observed in healthy elderly adults.