Visual field test

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(Redirected from Perimetry)

Visual Field Test

File:Visual Field Test.jpg
Visual Field Test

A Visual Field Test is a method used by eye care professionals to measure 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, requiring the patient to understand the testing instructions, fully cooperate, and complete the entire visual test in order to provide useful information.

Procedure[edit | edit source]

File:Visual Field Test Procedure.jpg
Visual Field Test Procedure

The most common type of visual field test in a clinical setting is known as a confrontation field test, where the examiner briefly flashes an object in the patient's peripheral field of vision. Other types of visual field tests include automated perimetry tests, where the patient sits in front of a concave dome and stares at an object in the middle. The machine then lights up dots around the dome, and the patient presses a button whenever they see a dot. The machine will then record each time the patient presses the button.

Purpose[edit | edit source]

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 ptosis or drooping, optic nerve disease, and diseases affecting the visual pathways within the brain. The visual pathways carry information from the eye to the visual or occipital cortex in the brain, where this information is processed into vision.

Interpretation[edit | edit source]

File:Visual Field Test Interpretation.jpg
Visual Field Test Interpretation

Interpretation of visual field tests can be challenging because there are many factors that can influence test outcomes, including the patient's alertness and understanding of the test, as well as the type of visual field test administered. However, in general, damage to the optic nerve can cause specific visual field defects. For example, damage to the optic nerve fibers that run near the nose can cause loss of the peripheral field on the opposite side. This condition is known as nasal step.

Limitations[edit | edit source]

While visual field tests are a valuable tool in diagnosing and monitoring many conditions, they do have some limitations. The test's effectiveness depends heavily on the patient's ability to understand and follow instructions. Some people may also have difficulty focusing on the target for the duration of the test. Children and those with certain cognitive or physical limitations may not be able to effectively participate in visual field testing.

See Also[edit | edit source]

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Contributors: Prab R. Tumpati, MD