The influence of age on the electroretinogram and visual evoked potential.

Changes in the ERG and VEP across the life span were investigated. The dark adapted and scotopic ERGs both showed a progressive increase in the implicit times of the A and B waves and a reduction in the amplitude of the AB configuration. There was also an increase in the implicit times of the oscillatory potentials of the photopic ERG. The flash and pattern onset-offset VEP both showed changes in waveform with age whilst the waveform of the pattern reversal VEP was constant. The amplitudes of the components of the flash and pattern reversal VEP were very high in the teenage group, but once reduced, were constant from the twenties onwards, showing no further consistent age changes. The latencies of the components of the pattern VEPs showed an increase with age which could be accounted for by the reduction in retinal illuminance due to the decrease in pupil diameter with age. However, the increase in the latency of the flash major positive (P2) component was greater than that expected from the decrease in retinal illuminance alone, suggesting that this is due to neural factors.