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An electroretinogram (ERG), or electroretinography, is a painless diagnostic procedure that evaluates the function of the retina, the light-sensitive lining on the back of the eye where light is focused. This test can aid in the diagnosis of several retinal conditions that can lead to serious complications, including permanent vision loss.
During the ERG procedure, the doctor places a contact lens on the eye to record electrical responses in retinal cells to flashes of light. By measuring these responses to the light under varying conditions, your doctor can determine how well the retina is functioning.
The entire ERG eye test takes 30-45 minutes on average and is available to our patients at Wills Eye Hospital. This procedure is performed with dilated pupils to achieve the most accurate results.
Patients receive anesthetic eye drops to minimize discomfort, so most report only mild sensations, including slight scratchiness or pressure from the electrode resting on the surface of the eye. A speculum is also used to gently keep the eyelids open throughout the test. While some irritation or sensitivity to the bright light is expected, significant pain is rare.
Electroretinography helps your doctor evaluate the health of your retina. More specifically, it allows your doctor to detect retinal diseases/conditions at early stages and has made timely intervention possible in many cases.
You might notice some mild irritation or light sensitivity afterward, and your vision could stay blurry for a few hours because of the dilation drops and electrode placement. Avoid touching or rubbing your eyes for at least an hour, and hold off on wearing contact lenses until the next day.
Sunglasses can help with discomfort from bright light while your pupils are still dilated. If you develop significant pain or any noticeable change in vision, contact your doctor.