Visual Field Testing
Your visual field refers to how much you can see around you, including objects in your peripheral (side) vision. Testing your visual field is important to the health of your eyes. Visual field tests help your ophthalmologist (Eye M.D.) monitor any loss of vision and diagnose eye problems and disease.
How is a visual field test performed?
The test can be done with either a dark screen on a wall or with a large, bowl-shaped instrument called a perimeter. One of your eyes is temporarily patched during the test. You will be instructed to look straight ahead at a fixed spot and watch for targets (spots of light) to appear in your field of vision. When you see the target, you press the indicator button. It is very important to always keep looking straight ahead. It is important to not move your eyes to look for the target; wait until it appears in your side vision.
Why are visual field tests important?
Initially, visual field tests help your ophthalmologist diagnose problems with your eyes, optic nerve or brain, including:
- Loss of vision
- Disorders of the retina
- Brain tumors
Visual field testing is the only way to document actual visual loss and whether the loss is progressing or remaining stable. If you are diagnosed with a particular disorder or disease, visual field tests may become a routine part of your treatment. People who have glaucoma or who are at risk for developing it take visual field tests every six months to a year to make sure their condition is stable and no vision loss has occurred.