Temporal summation in age-related maculopathy.

We measured temporal summation in subjects with atrophic age-related maculopathy (ARM) and age-matched control subjects at photopic and scotopic luminance levels. Although the ARM subjects did show longer critical durations in each case these differences were not statistically significant. This result, in conjunction with our earlier work on temporal discrimination, indicates that the processes which are responsible for temporal summation of the eye (presumably located at the receptors) are more resistant to the degenerative processes of ARM than are those responsible for temporal discrimination. This may be because the simple threshold procedure used here does not sufficiently stress the temporal response system to show a deficit.