Blind spot (vision)
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{{otheruses3|Blind spot}} <!--NB: There are other uses of "blind spot" in vision. -->
A '''blind spot''', also known as a [[scotoma]], is an obscuration of the [[visual field]]. A particular blind spot known as ''' <u> the </u> blind spot''', or '''physiological blind spot''', or '''punctum caecum''' in medical literature is the place in the visual field that corresponds to the lack of light-detecting [[photoreceptor cell]]s on the [[optic disc]] of the [[retina]] where the [[optic nerve]] passes through it. Since there are no cells to detect light on the optic disc, a part of the field of vision is not perceived. The [[brain]] fills in with surrounding detail and with information from the other [[eye]], so the blind spot is not normally perceived.
Although all [[vertebrate]]s have this blind spot, [[cephalopod]] eyes, which are only superficially similar, do not. In them, the optic nerve approaches the receptors from behind, so it does not create a break in the retina.
The first documented observation of the phenomenon was in the 1660s by [[Edme Mariotte]] in France, at the time when it was generally thought that the point at which the optic nerve entered the eye should actually be the most sensitive portion of the retina [http://home.snafu.de/pedasy/ascapap.htm].
== External links ==
*[http://ourworld.compuserve.com/homepages/cuius/idle/percept/blindspot.htm Blind spot]
[[Category: Eye|Blind spot (vision)]]
[[Category: Vision|Blind spot (vision)]]
[[de: Blinder Fleck (Auge)]]
[[fr: Point aveugle]]
[[he: הכתם העיוור]]
[[it:Punto cieco]]
[[ja: 盲点]]
[[nl:Blinde vlek (biologie)]]
[[no: Den blinde flekk]]
[[pl: Plamka ślepa]]
[[pt: Ponto cego]]
[[ru: Слепое пятно]]
[[sv: Blinda fläcken]]
[[zh:盲點 (眼)]]