Effects of dark adaptation on implicit time in the clinical electroretinogram

Electroretinograms were recorded from 11 normal human subjects during dark adaptation, either in full dark adaptation or in the presence of light backgrounds of various intensities. Although the amplitude varied considerably depending on the state of dark adaptation, the timing of the response appeared to be much less influenced. For practical purposes, in the absence of a significant background the timing of the response can be considered constant for a given intensity of stimulation, whatever the state of adaptation.