Four types of visual field testing methods

Published: 19th October 2009
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Also called side vision, one people's full horizontal and vertical vision range can be determined by a visual field test, which also detects potential blind spots in the visual field. Some eye and brain disorders are responsible for these visual field defects. Glaucoma, toxic exposure and retina damage can cause optic nerve damage and blind spots. Brain strokes and tumors may also affect the visual field.

A confrontation visual field testing can detect potential eye diseases and suggest for a further test. This test requires the patient to fixate on the doctor's eye and describe the different numbers of fingers, which are within your peripheral viewing field but on the far edges.

Automated perimetry tests can evaluate your vision field by flashing random lights of different strength (generated by computer) in your peripheral vision field while your eyes are staring on a source light straight ahead. The patient uses a button to indicate the presence of objects. There may be a blind spot, if you fail to see objects in certain portion of the visual field.

Doubled contrasting colored (such as black and white) bars that are flickering at different frequencies are used to test the response of photoreceptors within the retina. Optic nerve damage or certain areas vision loss of the visual field can be detected if the patient fails to see bars at certain frequencies.

The fourth method will be like this: based on the anatomical relationship between the retinal images and the visual field, a device will be placed on your cornea to detect its electrical impulses, which are in turn used to detect your retina's responses. This method is called electroretinogram. The patient's cornea should be treated with a topical anesthetic to ease any discomfort.

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