The human pattern ERG: alteration of response properties with aging.

The influence of aging on both the amplitude and the latency of transient and steady-state pattern electroretinograms (PERG's) was studied in 80 healthy participants ranging from 25 to 77 years of age (mean age, 55.3 years). Responses to counterphasing checkerboard patterns were recorded for each of 7 test conditions in which the spatial (i.e., check sizes 0.25, 0.50, 1.00, and 2.00 degrees) and temporal characteristics (i.e., counterphasing at either 2, 4, 8, or 16 rps) of the stimuli were varied. For both the transient and steady-state PERG's amplitude was inversely related to age (p less than 0.05 for each test condition). In general, PERG latency directly correlated with age, but this effect was less robust (p less than 0.05 for one transient condition and three of the four steady-state conditions). The influence of age on the spatial tuning of the PERG was minimal; the decrease in PERG amplitude and the increase in PERG latency as a function of age were essentially the same for all test conditions. However, the magnitude of the age-related reduction in PERG amplitude was observed to vary with temporal frequency, being largest for the steady-state condition (16 rps). The results from an experiment in which young subjects were tested while wearing opaque contact lenses with 2-mm artificial pupils suggest that senile miosis is a significant factor contributing to the age-related PERG amplitude and latency changes, but it does not fully account for the observed changes.