What is a visual field test?
A visual field test is a method of measuring an individual’s central and peripheral (side) vision. Visual field testing actually maps the visual fields of each eye individually.
Visual field testing is most frequently used to detect any signs of glaucoma damage to the optic nerve. In addition, visual field tests are useful for detection of central or peripheral retinal disease, eyelid conditions such as ptosis or drooping, optic nerve disease, and diseases affecting the visual pathways within the brain. The visual pathways carry information from the front of the eye to the visual pathway of the brain, where this information is processed into vision.
How is visual field testing done?
There are a variety of methods utilized to measure the visual fields. Virtually all visual field testing is performed one eye at a time. In all testing, the patient must fixate on a central target. Visual field testing is useful for the reasons:
- screening for glaucoma,
- testing patient with glaucoma for treatment response,
- screening and testing for lid droop or ptosis, particularly for insurance approval of lid lift surgical procedures,
- testing for macular diseases such as macular degeneration or toxicity from certain medications such as Plaquenil used for rheumatoid arthritis,
- testing for peripheral retinal disease such as retinal detachment or retinitis pigmentosa,
- testing for malingerers, or patients who may have secondary gains from poor vision, such as a false insurance claim,
- testing the function of the optic nerve looking for tumor, injury, poor circulation or stroke, compression from swelling in the eye socket or orbit, or severe dietary deficiency,
- testing the visual pathways to the brain, looking for tumor, brain swelling, injury, or poor circulation, and
- testing the visual or occipital cortex, looking for tumor, injury, brain swelling, or poor circulation.