Visual Evoked Potential Test

(VEP)

Definition

A visual evoked potential test (VEP) is used to look for problems in the brain that affect vision. The test machine records brain waves related to the visual nerves. This test can evaluate a large part of the brain.

Optic Nerve and Muscles

Reasons for Test

This test is often used to:

Diagnose and follow multiple sclerosis (MS)

Detect brain tumors, injuries, and strokes

Test vision in children and adults who are unable to read eye charts

There are many symptoms that might lead your doctor to order a VEP. You may be having double vision, blurred vision, or loss of part or all of your vision.

What to Expect

Prior to Test

You will be given instructions to prepare for the test such as:

Wash your hair but avoid hair chemicals (hairsprays and gels)

Get a good night’s sleep

Bring your corrective eyewear

Description of Test

Wires will be attached to your scalp with adhesives. A patch will be placed over one eye. You will watch a screen with your other eye. The process is then repeated with the other eye covered.

The wires will then be removed from your head.

After Test

You will be able to leave after the test is done.

How Long Will It Take?

About 45 minutes

Will It Hurt?

Results

Your doctor will discuss the results with you and what further treatment may be needed.

Call Your Doctor

Call your doctor if you have any concerns.

In case of emergency, call 911.

RESOURCES:

The National Multiple Sclerosis Society

http://www.nationalmssociety.org/

University of Michigan Health System

http://www.med.umich.edu/

CANADIAN RESOURCES:

BC Health Guide

http://www.bchealthguide.org/

University of Ottawa Eye Institute

http://www.eyeinstitute.net/main.html/

References:

Evoked potential studies. St. John's Mercy Healthcare website. Available at: http://www.stjohnsmercy.org/healthinfo/test/neuro/TP014.asp . Accessed September 8, 2005.

Merck Medicus website. Available at: http://www.merckmedicus.com/pp/us/hcp/thcp_raj_content.jsp?pg=/ppdocs/us/hcp/content/raj/chapters/raj-ch-026-s003.htm . Accessed September 8, 2005.

Last reviewed October 2009 by Christopher Cheyer, MD and Brian P. Randall, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.