Definitions for visual acuity
This page provides all possible meanings and translations of the word visual acuity
Random House Webster's College Dictionary
vis′ual acu′ity(n. .)
acuteness of the vision as determined by a comparison with the normal ability to identify certain letters at a given distance, usu. 20 ft. (6 m).
Origin of visual acuity:
acuity, visual acuity, sharp-sightedness(noun)
sharpness of vision; the visual ability to resolve fine detail (usually measured by a Snellen chart)
Visual acuity is acuteness or clearness of vision, which is dependent on the sharpness of the retinal focus within the eye and the sensitivity of the interpretative faculty of the brain. Visual acuity is a measure of the spatial resolution of the visual processing system. VA is tested by requiring the person whose vision is being tested to identify characters on a chart from a set distance. Chart characters are represented as black symbols against a white background. The distance between the person's eyes and the testing chart is set at a sufficient distance to approximate infinity in the way the lens attempts to focus. Normal visual acuity is commonly referred to as 20/20 vision, the metric equivalent of which is 6/6 vision. At 20 feet or 6 metres, a human eye with nominal performance is able to separate lines that are one arc minute apart. A vision of 20/40 is considered half as good as nominal performance. A vision of 20/10 is considered twice as good as nominal performance. In an eye exam, lenses of varying powers are used to precisely correct for refractive errors. English alphabet letters are typically used as most people will recognise them but other symbols are also used.
U.S. National Library of Medicine
Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.
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