Changes in the electroretinogram (ERG) are studied in patients with large chorioretinal
scars and certain hereditary retinal diseases. Amplitude and implicit time of the ERG
responses are shown to behave independently of one another in these conditions.
Chorioretinal destruction produces a reduction in amplitude but no change in implicit time.
Hereditary disease leads to reduction in amplitude which can be accompanied by changes
in implicit time. Some degenerations produce changes in implicit time before changes in …