Electroretinography

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Contact lens electrode on eye

Electroretinography is a test to measure the electrical response of the eye's light-sensitive cells (rods and cones).

ERG

While you are comfortably seated in a chair, the health care provider places numbing drops into your eyes, so you do not feel pain during the test. Your eyes are then propped open and 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.

No special preparation is necessary for this test.

The probes that rest on your eye may feel like an eyelash. The test takes about one hour to perform.

Both hereditary and acquired disorders of the retina can be evaluated with this test. It is also useful in determining if retinal surgery is recommended.

Review Date: 02/22/2007
Reviewed By: Manju Subramanian, MD, Assistant Professor in Ophthalmology, Vitreoretinal Disease and Surgery, Boston University Eye Associates, Boston, MA. Review provided by VeriMed Healthcare Network.