Electroretinography and Its Clinical Application

WHENEVER a light stimulus is thrown upon a functioning retina, a typical, reproducible action current can be obtained. Until recently the electric responses of the retina to light stimulation have been used almost exclusively as a tool for the study of retinal physiology in animals. Improved methods of derivation of retinal action currents and other methodologic improvements have made it possible to extend this study also to the human electroretinogram. In the past few years this method of investigating retinal function has gained increasing attention among ophthalmologists in the hope that it may contribute toward the understanding and solution of clinical problems. The electroretinogram is a complicated polyphasic response which varies in its properties with the intensity, size, duration, and wave length of the stimulus and with the state of adaptation of the stimulated retina. When stimuli of short duration are employed, the normal electroretinogram consists mainly of a small,