Chapter

Visual Evoked Responses

Jay A. Liveson and Dong M. Ma

in Laboratory Reference for Clinical Neurophysiology

Published in print May 1999 | ISBN: 9780195129243
Published online March 2012 | e-ISBN: 9780199847792 | DOI: http://dx.doi.org/10.1093/acprof:oso/9780195129243.003.0014
Visual Evoked Responses

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Visual evoked potentials provide a quantitative measure of the visual system. The function measured includes that of the optic nerve, through the optic chiasm and tract, to the lateral geniculate bodies, and the geniculocalcarine projection to the visual cortex. The use of small-sized stimuli tests the foveal region, emanating primarily from the central fifteen degrees. The most reliable information relates to lesions of the optic nerve, and is derived by individual testing of each eye. An important application of visual evoked responses is as a screen for multiple sclerosis lesions. Abnormalities have also been shown in other conditions such as glaucoma, parkinsonism, and cortical blindness. It can also be used to measure visual acuity in infants. Since the response relies on a visual image reaching the retina, it is important to screen initially for any significant decrease in visual acuity. If possible, this should be corrected. If not, flash stimuli may yield some information, although this may or may not be as sensitive a test.

Keywords: visual evoked potentials; visual evoked responses; retina; optic nerve; foveal region; lesions; multiple sclerosis; visual acuity; stimuli

Chapter.  1552 words.  Illustrated.

Subjects: Neuroscience

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