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Visual Evoked Potential (VEP)

What is a Visual Evoked Potential?

This is a test of the optic nerve which is the pathway between the eye and the back of the brain. You will be asked to look at the centre of a television screen that has a moving black and white chequer-board pattern. Each eye is tested separately, with a patch covering the other eye.  This is a painless procedure and there are no after effects.

The time taken for this test is approximately 45 minutes.

How is it performed?

The test is performed by attaching some small discs to your scalp which record the electrical responses from your brain.  There will be three leads at the back of your head, one behind each ear and two on the top of the head.  The leads are attached with a sticky white paste which washes out of your hair easily.

You will be asked to concentrate on the centre of a pattern on a screen for 2-3 minutes at a time. Each eye is usually tested twice.

How do I prepare for the test?

Please ensure your hair is clean and free from hairspray and oil. 

If you are taking medication please continue to take it and bring a list of your medication with you.

Continue to eat meals as normal.

There are no side effects from the test.

How long will I have to wait?

You have been given a specific appointment time and patients are usually seen on time.  It is important that you arrive on time.  Please allow plenty of time for parking.

When will I get the results?

The results are sent to the doctor that referred you for the test and are usually available within seven days.

If you have any concerns or questions please speak to a Clinical Physiologist on the number below.


Neurophysiology Department   01422 222976