Many diseases affect the speed at which signals travel along the optic nerve to the brain, resulting in decreased vision. The Visual Evoked Potential (VEP/VER) measures the time it takes the signal to reach the brain from the eye. This test is useful in better understanding changes in visual function and in the diagnosis and treatment of many conditions including optic neuritis, multiple sclerosis, brain injury, stroke, and other vision-related issues such as glaucoma.
VEP uses visual stimuli in different patterns and contrasts to elicit the electrical response from your retina. During the test, you will be asked to focus on a screen with black and white patterns which “flip” over quickly. The computer then records the electrical signal produced. It is similar to an EKG, but for your entire vision system. The signal between the two eyes and also to what is considered normal is then compared. A baseline can be used for comparison over time and aid in detecting small changes in function before the patient actually notices.