The electroretinography (ERG) test measures the electrical response of the retina to light. It is performed by placing an electrode on the cornea of the eye after it has been numbed with eye drops. Disorders of the retina can be evaluated with this test. It can also help to determine if retinal surgery may be helpful.
Review Date 8/18/2020
Updated by: Franklin W. Lusby, MD, ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.