Electroretinography is a test to measure the electrical response of the eye's light-sensitive cells, called rods and cones. These cells are part of the retina (the back part of the eye).
ERG; Electrophysiologic testing
How the Test is Performed
While you are in a sitting position, the health care provider places numbing drops into your eyes, so you will not have any discomfort during the test. Your eyes are held open with a small device called a retractor. An electrical sensor (electrode) is placed on each eye.
The electrode measures the electrical activity of the retina in response to light. A light flashes, and the electrical response travels from the electrode to a TV-like screen, where it can be viewed and recorded. The normal response pattern has waves called A and B.
The doctor will take the readings in normal room light and then again in the dark, after allowing 20 minutes for your eyes to adjust.