Sometimes, a patient’s problem lies with the brain or nervous system rather than the eyes themselves. To figure out if this is the case, we can perform a VEP or Visually Evoked Potential.
To perform this test, we place three sensors on the patient’s head to pick up the brain waves. We provide the patient with the correct vision prescription for the task and ask them to wear the glasses. To evoke the potential we like to see, we ask the patient to focus on a monitor with an alternating checkerboard pattern. This shift in color stimulates a response from the brain. The VEP measures the time it takes for the visual stimulus received by the eye to reach the part of the brain where it is “translated,” the occipital cortex. If the response is abnormal, we can start to understand the real problem the patient experiences.
Below is an animation of what the VEP test looks like to the patient.
The VEP can be used to help diagnose conditions such as:
Tumors or Lesions compressing the Optic Nerve
Possible reasons for doctor to call for a VEP include:
Loss of vision
Double or blurry vision
Weakness of arms or legs
Change in color vision
If you have any questions about the VEP, please feel free to contact us. We would love to help you understand why we do what we do.