The VEP examination tests the optic nerve pathway to determine how fast the signal from the optic nerve travels to the occipital lobe. This is typically accomplished by exposing the nerve to certain visual stimulations. The most common method of stimulation used is known as “the checkerboard test.” However, there are several methods of stimulating the optic nerve. Other techniques that are occasionally employed consist of LED goggles or a photic flash stimulator.

VEP’s are typically administered because a patient is suffering from blurry vision or diminished vision, or the patient has a known history of optic neuritis.

A VEP is a painless test. You will not feel any pain or discomfort during the test. Your eye may become a bit fatigued.

You can expect to sit in a darkened room, where the technician will first take some initial measurements with a grease pencil. This ensures that the electrode placement is accurate. This pencil will come off after the testing.

After ensuring that you are as comfortable as possible, the technician will apply a gel that will allow the electrodes to connect effectively. The technician will then place several electrodes on your head; the number of recording electrodes placed on your scalp may vary, but typically six are used. The technician will check the connections of all the electrodes to insure good conductivity.

The technician will then check your vision with a vision card. Next, you will be shown a checkerboard pattern consisting of black and white squares. You will be directed to focus on the checkerboard pattern with one eye at a time. The technician will provide intermittent brief periods of rest during the examination. The process will then be repeated with your other eye.

Typically, the test is usually about 45 minutes, but it may take up to 1 hour.