Electroretinography

Electroretinography (ERG): A test in which the electrical potentials generated by the retina of the eye are measured when it is stimulated by light. In an ERG, an electrode is placed on the cornea at the front of the eye. The electrode measures the electrical response of the rods and cones, the visual cells in the retina at the back of the eye. An ERG may be useful in the evaluation of hereditary and acquired disorders of the retina. A normal ERG shows the appropriate responses with increased light intensity. An abnormal ERG is found in conditions such as arteriosclerosis of the retina, detachment of the retina, and temporal arteritis with eye involvement. The instrument used to do electroretinography is an electroretinograph and the resultant recording is called an electroretinogram.