Visual Field Test
A visual field test can detect problems with vision in any part of the visual field, which is the entire area one can see.
The visual field includes central and peripheral (side) vision. Changes in the visual field may be difficult to notice since both eyes are generally used at the same time. One eye can sometimes compensate for some vision loss in the other. A problem may not be detected until each eye is tested separately.
The visual field test provides information that no other test can. It is used to detect many diseases, such as glaucoma or retinitis pigmentosa, which affect the eye, optic nerve, and brain. It can also help diagnose brain tumors, strokes, and other conditions. Visual field testing helps diagnose the disease and can follow the progress of the disease and its treatment.
During a visual field test, one eye is temporarily patched while the other eye is being tested. You are asked to look straight ahead at a fixed spot and watch for targets to appear in your field of vision.
The most common testing method uses small fixed targets that appear briefly as bright or dim lights (called computerized static perimetry). You sit in a chair facing a bowl-shaped instrument and indicate when you see the targets appear by pressing a button. This test usually takes only a few minutes for each eye.