What is a VER test? (Visual Evoked Response)

This is a test of your visual system to see how well it is working. It specifically evaluates your optic nerves with signals going down the visual pathway. The computer adds them up and creates a waveform for your doctor to view. To get these signals you have to watch a T.V. screen with a special checkerboard pattern on it that is moving.

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Why do people have VER’s?
Some common symptoms patients have when they come for this test are: double vision, blurred vision, eye injuries, head injuries, weakness of eyes, arms, legs, and decreasing vision, etc.

Does a VER test hurt?
No, the test is not painful. All you do is watch a T.V. with reversing checkerboards during the test.

Can you sleep during a VER?
No. It is very important that you be wide-awake and alert for this test. Even drowsiness can affect your test results, making them appear abnormal when they may actually be very normal.

What do VER’s show?
VER’s tell us about the health of your visual system and if there is any damage or problems that might be the cause of your symptoms. The VER is part of an “internal” check of the visual system. This is the part that is located in the brain. Your eye doctor checks the “external” factors of your vision.

The wave form, shape, size and when it happens are what the doctor looks at to determine whether or not there is a problem in your visual system.

How long does a VER take?
The VER test takes about 45 minutes.

How to get ready for a VER:

1. Wash your hair if possible – no sprays or oils.
2. Continue taking prescribed medications unless your doctor tells you not to.
3. Bring ALL of your glasses to the lab, regardless of the reason you wear them.
4. Be well rested and as wide-awake as possible.

What happens when you come to the laboratory?
A technician will be with you throughout the test and give you instructions as needed. The following activities will occur during your visit to the laboratory:

1. The technician will first check your vision with an eye chart so we will have a basic idea how well you will be seeing during the test. Don’t forget your glasses!
2. Your head will be measured so we know where the seven electrodes will be applied.
3. Each spot is then scrubbed with a special solution and gauze.
4. Electrodes go on with paste.
5. Nothing goes in or under your skin.
6. The technician ensures there is a good electrical connection by testing each electrode on a special meter.
7. The test begins: You will be seated in a lounge chair, reclined to a certain distance from a T.V. screen, and asked to relax. First you will close both eyes for about a minute while the technician runs a bit of EEG; then a patch will be placed over your left eye for the first part of the test. A total of six different tests or “trials” will be done, each lasting only two minutes. During each trial, all you have to do is to stare at a little red dot on the T.V. screen and be as still as possible. Your eyes are patched alternately until each has been tested twice and both eyes are tested together twice.
8. The test ends: The technician will remove the electrodes with warm water. You might want to wash your hair afterwards, unless your activities have been restricted.

Your doctor will tell you the results of your test.