Temporal Aspects of the Human Electroretinogram

Abstract

During the past decade intensive work by psychologists, physiologists, and ophthalmologists has shown that the human electroretinogram (ERG) is a result of two basic forms of response—scotopic and photopic. The differentiation of these two components has been achieved through the study of the ERG in normal, color-blind, and night-blind subjects, under different states of adaptation, with stimuli of varying wavelengths and intensities. The scotopic and photopic components of the human ERG are similar in that each consists of a negative deflection succeeded by a positive one. There is a difference, however, in their temporal characteristics, the photopic response following a more rapid course than the scotopic response. Furthermore, the photopic positive wave (x-wave) maintains a constant latency and implicit time,* regardless of the experimental condiregardless of the experimental conditions, tions, whereas the scotopic positive wave (b-wave) shows a marked variation. It is the purpose of this investigation to study the