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Ency. home > Test > E > Electroretinography

Electroretinography   

Overview | Risks | Results

Alternative names:

ERG

Definition:

A test where an electrodes is placed on the cornea and the shin near the eye to measure the electrical response of the rods and cones (light sensitive cells) of the eye.

How the Test is Performed

You are asked to assume a comfortable position, usually sitting in a chair. Anesthetic drops are placed in your eyes, causing them to become numb. Your eyes are then propped open and an electrode is placed on each eye. The electrodes measure the electrical activity of the retina to light. The information that comes for the electrodes goes to a monitor where it can be viewed and recorded.  The normal pattern has waves called the A wave and the B wave.

The doctor will record the readings in normal room light and then after 20 minutes in the dark to allow dark adaptation.  A light is flashed, and the electrical response to the flash is recorded.  

How to Prepare for the Test

Adults:
No special preparation is necessary for this test.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

How the Test will Feel

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

Why the Test is Performed

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.

Ency. home > Test > E > Electroretinography

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