Visual Evoked Potential Test
A visual evoked potential test (VEP) is used to look for problems in the brain that affect vision. A machine records brain waves related to the nerves that make up the visual pathway. 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)
- 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. Avoid hair chemicals (eg, hair sprays, gels).
- Get a good night’s sleep.
- Bring your corrective eyewear.
Description of Test
Wires will be attached to your scalp with adhesive. A patch will be placed over one eye. You will watch a screen with your other eye. The process is then repeated with the opposite eye covered.
The wires will be removed from your head.
You will be able to leave after the test is done.
How Long Will It Take?
About 45 minutes
Will It Hurt?
National Eye Institute
National Multiple Sclerosis Society
Canadian Association of Optometrists
Canadian Ophthalmological Society
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 November 2009 by
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.
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