Difference between revisions of Visual acuity
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Visual Acuity is the measurement of how well the vision system as a whole is recognizing what it sees. This is typically measured with a [[Snellen chart]] and expressed as the distance you need to be from the chart to recognize the characters over the distance that someone with normal vision can recognize the characters, so 10/400 would be very bad, 20/20 is | Visual Acuity is the measurement of how well the vision system as a whole is recognizing what it sees. This is typically measured with a [[Snellen chart]] and expressed as the distance you need to be from the chart to recognize the characters over the distance that someone with normal vision can recognize the characters, so | ||
* 10/400 would be very bad, | |||
* 20/20 is (by definition) normal, and | |||
* 40/20 is excellent. | |||
[[Refraction]] is only one part of visual acuity. Various medical conditions can cause physical blockage/dispersion of light in the eye, problems detecting light in the eye, or problems with the visual processing that turns a series of electrochemical signals into a picture in our mind's eye. See an [[optometrist]] if your vision can't be corrected with [[refraction]]. | [[Refraction]] is only one part of visual acuity. Various medical conditions can cause physical blockage/dispersion of light in the eye, problems detecting light in the eye, or problems with the visual processing that turns a series of electrochemical signals into a picture in our mind's eye. See an [[optometrist]] if your vision can't be corrected with [[refraction]]. | ||
=See Also= | |||
* [[Index of Refraction]] | |||
==References== | ==References== | ||