The Electroretinogram Records the Electrical Response of the Retina to a Flashing Light

The Clectroretinogram (ERG) is a clinical electrophysiological recording from the cornea and skin near the eye. It records the electrical response of the retina to a light flashed into the eye. It has three waves: the A wave, corresponding primarily to the activation of visual pigment and photoreceptors; the B wave, caused primarily by the response of retinal bipolar cells; and a slower C wave, thought to originate in the pigment epi­thelium. I he ERG is a fairly simple, general electrodiagnostic tool for assessing some forms of retinal dysfunction or degeneration.