Associated conditions: Diabetic retinopathy, other retinal conditions.
What takes place: Before recording your ERG, your pupils will be dilated. An electrode (a small silver disk) will be attached to your forehead with tape. Then we will place numbing drops in your eyes and insert special contact lenses in them. The contact lenses should not cause you any discomfort. The contact lenses will sense small electrical signals that are generated by your retina. In the first part of the test, you will look at the center of a black and white checkerboard screen that will flicker for 30 seconds at a time. This will be repeated 16 or more times. In the second part of the test, you will look inside a sphere. Flashes of light will flicker for 20 seconds at a time. This will be repeated four or more times. In both parts of the test, you will be asked not to blink or move your eyes during the 20 to 30 second flickers, but you may do so between them. The test will take about an hour. You should not rub your eyes after the test. If you wear contact lenses, please bring your eyeglasses with you because it is better to avoid wearing contacts immediately after the test.
Risks: The numbing drops and the contact lens electrode may cause slight discomfort. There is a small chance of a corneal abrasion (scratch) from the contact lens electrode. In the event that you experience a corneal abrasion, an antibiotic ointment will be placed in your eye and a patch will be placed over your eye. You will need to see a doctor the next day.