Visual Field Test
A comprehensive eye exam typically includes visual field testing to assess the full horizontal and vertical range and sensitivity of your vision. Visual field tests provide a subjective measure of central and peripheral vision, or side vision, and is commonly used to determine the severity of, and monitor glaucoma.
Visual field tests are used to detect blind spots that could be an indication of eye diseases. The size and shape of a blind spot indicate the type and severity of diseases of the eye, optic nerve and visual structures within the brain. For example, optic nerve damage, resulting from glaucoma, produces a very specific visual field defect, while other eye and brain disorders cause different degrees of peripheral vision loss and/or other visual field abnormalities. Brain abnormalities, such as those caused by strokes or tumours, can impact the visual field. Moreover, the location of the stroke or tumour in the brain can frequently be diagnosed by the size, shape and location of the visual field defect.
The most common visual field test uses a light spot that is repeatedly presented to an individual in various locations of their peripheral vision. Digital imaging of the optic nerve and surrounding tissues is an objective test that can also be used to assess field of vision and detect glaucoma damage and progression. Well equipped clinics use both tests, because occasionally the optic nerve changes before the visual field or changes to the visual field can be observed before damage to the optic nerve is detected. Combined, the two tests equip optometrists with the information necessary to properly diagnose and treat patients.
Now you know the importance of chasing lights and clicking buttons during your eye exam!