Visual Evoked Potential (VEP)

What is Visual Evoked Potential (VEP)?

VEP is a test that records how quickly and effectively electrical signals in the brain is received, in response to visual stimulation. 

Your doctor may recommend this test to:

• Check the visual pathway between the eyes and the visual cortex. The visual cortex is the part of the brain that enables us to see. 
• Help diagnose conditions of the brain and spinal cord such as multiple sclerosis
• Investigate blurred or reduced vision 

How should I prepare for VEP?

• Bring your spectacles, contact lens or any other visual aids that help you see better.
• Avoid using hair conditioner and styling products e.g. foam, cream, gel, oil
• Not required to fast
• Continue with your regular diet and medications 

How is VEP performed?

The test is done by a neurotechnologist and will take approximately 45 minutes.

• This test is done while you sit on a chair.
• Your scalp is cleaned using a gel.
• Small markings are made on your scalp. 
• Electrodes are attached to the marked areas using a safe and washable paste.
• One of your eyes will be covered with clean cotton gauze.
• You will be asked to look at some patterns on a monitor screen about 1-1.5metres away. Please remain relaxed and alert. If you are sensitive to flashing lights or images, inform your doctor.
• The electrodes record your brains' response to the patterns you see on the TV screen. 
• The same process is repeated on the other eye
• Once the test is done, the electrodes are removed, and you can go home.
• A detailed report will be sent to your doctor within two weeks. Your doctor will discuss the findings with you at your next appointment.

Frequently Asked Questions about VEP

Is the test safe?

Yes, the test is: 

• Non-invasive (no needles)

• No external electric current or discharges. The test only records your brain’s electrical activity – it does not send electricity into your body.

• A neurotechnologist will be present throughout the process. If you feel unwell, please inform the neurotechnologist.

Does the test affect my vision?

No. You just need clean and dry hair, without any oils, sprays or gels.

Can I use Medisave to pay for this test? 

This test may be claimable under:

• Flexi-MediSave for Seniors; or

• Outpatient scans for diagnosis or treatment of a medical condition.

Please refer to the Ministry of Health's Outpatient Care page for the latest claim limits and eligibility criteria. 

The information is correct as of July 2026 and subject to revisions without notice.
Content adapted from NNI Neurodiagnostic Laboratory (NDL), NNI@TTSH.