Skip to content
left end
left end
right end


What is a visual evoked potential?

A test that records the function of the optic nerve pathway between the eye and brain using a flashing light or checkerboard on a monitor screen.

What should I do before the test?

Please wash your hair and do not use any hair products.

Take your medication as usual unless directed by your doctor

Eat as normal

Bring a list of your medication with you

If you wear glasses or contact lenses please bring or wear them to the appointment.

Visual page

What will happen during the test?

  • A healthcare scientist will explain the procedure to you and answer any questions you may have. They will need to take a clinical history from you.
  • You may be asked to look at letters on a chart, similar to those used at the opticians.
  • Your head will be measured using a tape measure and small marks drawn on with a skin pencil (this will wash off easily)
  • Electrodes (wires with small metal disks on) with be attached to your head using sticky paste or glue (this will also be removed easily)
  • Other sticker electrodes will be attached to the face and under the eyes.
  • You will be asked to sit in a chair and look at a checkerboard screen or flashing light.
  • This will be repeated one eye at a time.
  • The healthcare scientist will remove the electrodes and wipe clean your hair with water.
  • The whole test should take under an hour. If your child is the patient this time can vary depending on their cooperation and attention to the screen or light.

How will I get my results?

The results will be analysed by a consultant neurophysiologist and sent back to the doctor who requested the test. This should happen within 10 working days of the test.

Contact details

To change your appointment or if you have any questions please contact the neurophysiology department on 0117 3428254

Please allow plenty of time to get to your appointment. Parking is particularly difficult. If you are more than 15 minutes late we may not be able to perform the test. If you are unable to attend your appointment please inform the department as soon as possible by calling the number above.