The a-wave of the ERG as a quantitative measure of human receptor activity

For over fifty years, the leading edge of the a-wave has been associated with receptor activity 1 . Uncertainty remains, however, about the answers to two basic questions: First, to what extent does the a-wave reflect receptor activity? For example, can we assume that the amplitude of the a-wave is linearly related to the size of the receptor's response? And, second, can we associate specific defects in receptor function with alterations in the leading edge of the a-wave? We are addressing these questions by comparing the leading edge of the rod a-wave to models of the rod receptor 2,3 .