A visual field test measures the quality of a patient’s side (peripheral) vision. It is a straightforward test, painless, and does not involve eye drops. Each eye is tested separately, so an eye patch will be placed over the eye not being tested. The patient is placed in front of the visual field analyzer, with their head stabilized using a chin rest and a forehead rest, and asked to fixated on a light straight ahead. A lens to aid in focusing may or may not be placed in front of his/her eye. Lights will begin to flash to the sides of the patient’s vision, and in response to these lights, the patient will press a button to indicate that the light was in fact seen. The lights can be very bright, or very dim, and some lights will actually flash in an area called the blind spot. These lights should not be seen if a patient is fixating properly. The entire test should take 15-45 minutes.
Measurement of a patient’s visual field is performed for a number of different reasons. Glaucoma is an eye disease that causes damage to peripheral vision, and is the most common reason why visual field testing is performed.
A binocular visual field test may be required for patients as a requirement for driver’s license renewal. This test is performed with both eyes open and working together. It is generally a quick test, taking 10-15 minutes.