Visual Field Testing
Visual field testing actually maps the visual fields to detect any early (or late) signs of glaucomatous damage to the optic nerve. In order to find and follow glaucoma, visual fields are measured by a computer one eye at a time. One eye is covered and the patient places his or her chin in a type of bowl. Lights of various intensity and size are randomly projected around inside of the bowl. When the patient sees a light, he or she pushes a button. This process produces a computerized map of the visual field, outlining the areas where each eye can or cannot see. In glaucoma, there are characteristic changes in the visual field examination.
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What is a visual field test?
A visual field test is a method of measuring an individual's entire scope of vision, that is their central and peripheral (side) vision. Visual field testing maps the visual fields of each eye individually and can detect blind spots (scotomas) as well as more subtle areas of dim vision. The visual field test is a subjective examination, so the patient must be able to understand the testing instructions, fully cooperate, and complete the entire test in order to provide useful information.
What is a visual field test used for?
Visual field testing is most frequently used to detect signs of glaucoma damage to the optic nerve. In addition, visual field tests are useful for detection of central or peripheral retinal diseases of the retina, eyelid conditions such as drooping (ptosis), optic nerve damage and disease, and conditions affecting the visual pathways from the optic nerve to the area of the brain (occipital cortex) where this information is processed into vision.
The following are uses of visual field testing:
- Screening for glaucoma: Peripheral vision loss is often an early and subtle sign of glaucoma. Visual field tests are helpful in making the diagnosis of glaucoma, and repeat testing is used to monitor treatment.
- Screening and testing for lid droop (ptosis)
- Testing for toxicity from certain medications (for example, screening for toxicity from hydroxychloroquine [Plaquenil], which can affect the central retina)
- Measuring the extent of retinal diseases, such as retinitis pigmentosa
- Detecting conditions affecting the optic nerve, such as tumors, injury, poor circulation or stroke, optic neuropathy, swelling of the optic nerve (optic neuritis), compression from swelling in the eye socket or orbit, and severe nutrient deficiencies
- Detecting conditions that affect the visual pathways from the optic nerves to the occipital lobe of the brain, including tumors, inflammatory disease, increased intracranial pressure, injury, poor circulation, or stroke
- Testing for malingering behavior or factitious disorders
Medically Reviewed by a Doctor on 2/7/2017