Source:http://linkedlifedata.com/resource/umls/id/C0180683
UMD: Graphic recorders of the changes in electrical potential on or near the surface of the cornea to a reference distal point on the body, following stimulation of the retina by light (i.e., flashes of white light). These recorders include a primary electrode (typically gold, platinum, or silver), a reference electrode located almost anywhere in the body (e.g., cheek, earlobe), and an amplifier that boosts the bioelectrical potential. Some recorders are compatible with personal computers for waveform storage and analysis. Electroretinographs are used in the diagnosis of retinal degeneration, night blindness, and circulatory disturbances of the retina.