Blind spot ( vision ) - wikipedia Blind spot ( vision ) For other uses, see Blind spot ( disambiguation ). This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( November 2011 ) Vertebrate Octopus In vertebrate eyes, the nerve fibers route before the retina, blocking some light and creating a blind spot where the fibers pass through the retina and out of the eye. In octopus eyes, the nerve fibers route behind the retina, and do not block light or disrupt the retina. In the example, 4 denotes the vertebrate blind spot, which is notably absent in the octopus eye. In both images, 1 denotes the retina and 2 the nerve fibers, including the optic disc ( 3 ). Distribution of rods and cones along a line passing through the fovea and the blind spot of a human eye A blind spot, scotoma, is an obscuration of the visual field. A particular blind spot known as the physiological blind spot, `` blind point '', or punctum caecum in medical literature, is the place in the visual field that corresponds to the lack of light - detecting photoreceptor cells on the optic disc of the retina where the optic nerve passes through the optic disc. Because there are no cells to detect light on the optic disc, the corresponding part of the field of vision is invisible. Some process in our brains interpolates the blind spot based on surrounding detail and information from the other eye, so we do not normally perceive the blind spot. Although all vertebrates 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 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 ; however, Mariotte 's discovery disproved this theory. The blind spot is located about 12 -- 15 ° temporally and 1.5 ° below the horizontal and is roughly 7.5 ° high and 5.5 ° wide. Contents 1 Blind spot test 2 See also 3 References 4 External links Blind spot test Demonstration of the blind spot Instructions : Close one eye and focus the other on the appropriate letter ( R for right or L for left ). Place your eye a distance from the screen approximately equal to 3 × the distance between the R and the L. Move your eye towards or away from the screen until you notice the other letter disappear. For example, close your right eye, look at the `` L '' with your left eye, and the `` R '' will disappear. See also Filling - in Horizontal eccentricity References Jump up ^ Brian A. Wandell ( 1 January 1995 ). Foundations of Vision. Sinauer Associates. ISBN 978 - 0 - 87893 - 853 - 7. Jump up ^ Gregory, R., & Cavanagh, P. ( 2011 ). `` The Blind Spot ''. Scholarpedia. Retrieved on 2011 - 05 - 21. Jump up ^ MIL - STD - 1472F, Military Standard, Human Engineering, Design Criteria For Military Systems, Equipment, And Facilities ( 23 Aug 1999 ) PDF External links `` Amsler Grid '' Test from Ossibus Software Blind spots Blind spot test Blind spot map tool Phenomena of the visual system Entoptic phenomena Blind spot Phosphene Floater Afterimage Haidinger 's brush Prisoner 's cinema Blue field entoptic phenomenon Purkinje images Other phenomena Aura Form constant Scintillating scotoma Palinopsia Visual snow Afterimage on empty shape Cosmic ray visual phenomena Scotopic sensitivity syndrome Retrieved from `` https://en.wikipedia.org/w/index.php?title=Blind_spot_(vision)&oldid=791695168 '' Categories : Eye Vision Hidden categories : Articles needing additional references from November 2011 All articles needing additional references Talk Contents About Wikipedia বাংলা Български Català Čeština Deutsch Ελληνικά Español Esperanto فارسی Français Hrvatski Bahasa Indonesia Italiano עברית Қазақша Lietuvių മലയാളം Bahasa Melayu Nederlands 日本 語 Norsk Polski Português Русский Simple English Slovenčina Српски / srpski Svenska Татарча / tatarça ไทย Українська اردو 中文 Edit links This page was last edited on 21 July 2017, at 22 : 15. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: blind spot is located in the area of the retina
Answer: 12–15° temporally