Electrophysiology Testing for Glaucoma

Electrophysiology testing allows Dr. Narain to diagnose and follow the progression of glaucoma and other vision disorders.

What is Electrophysiology Testing for Glaucoma?

Electrophysiology testing allows Dr. Narain to diagnose and follow the progression of glaucoma and other vision disorders. Vision is the result of electrical signals that travel between the retina and the part of the brain involved with vision (the occipital cortex). Electrophysiology testing checks to see how well the visual nerve pathway is at sending electrical signals needed for vision. These tests measure electrical activity that occurs in your eye when you look at something.

Electrophysiology testing allows for earlier detection of glaucoma, which allows for earlier treatment and greatly improved outcomes. Functional changes often occur before structural changes in glaucoma and it is important to catch optic nerve dysfunction before the nerve is permanently damaged.

Using these tests, we can diagnose glaucoma before patients have any visual symptoms.


What are the Different Tests?

Electrophysiology testing includes:

  • Electroretinography (ERG), which measures the retina’s electrical response while you look at flashes of light or different patterns. An ERG test can check for diseases and problems of the retina.
  • Visual evoked potential (VEP), which tests the electrical activity in the entire visual pathway. A VEP test can find issues by showing how brain waves respond to certain things you look at during the test.

Should I Prepare for Electrophysiology Testing?

You won’t need to do anything in preparation for your test. Follow any instructions that Dr. Narain gives you about what to do before and after testing.

What Can I Expect During Each Test?

During electroretinography (ERG), tiny electrodes are placed on your forehead and on your lower eyelids. The test records the electrical response in your eye as you look at flashes of light or a pattern of images. The test takes about 10 minutes to complete.

During visual evoked potential, a computer records changes in your brain waves while you look at checkered patterns. Electrodes are placed on your forehead, temple, and scalp, near the areas of your brain involved with vision. For several minutes, you will look at repeated patterns that appear in quick flashes on a screen. The test measures the time of response and the brain’s electrical activity.

Request an Appointment in San Jose or Gilroy, California

At South Bay Retina, we provide electrophysiology testing for glaucoma and other eye conditions. To schedule with Dr. Narain, our experienced ophthalmologist and retina specialist, call (408) 294-3534 for our San Jose and Gilroy office. You can also schedule online using the button below.


Concerns treated by Electrophysiology Testing for Glaucoma*

Call us at (408) 294-3534 or schedule online.

San Jose Office

Gilroy Office


We're happy to answer any questions you may have, feel free to call us at
(408) 294-3534