Editing Retinal scan (section)

{{Short description|Biometric method for identity verification}}
{{for|diagnostic retinal examination|Fundus photography|Ophthalmoscopy}}

[[Image:Retina_camera_controls.jpg|thumb|A close-up view of the controls of a Topcon retinal camera]]A '''retinal scan''' is a [[biometric]] technique that uses unique patterns on a person's [[retina]] blood vessels. It is not to be confused with other ocular-based technologies: [[iris recognition]], commonly called an "iris scan", and [[eye vein verification]] that uses scleral veins.

The [[human]] retina is a thin [[Tissue (biology)|tissue]] made up of [[Nerve|neural cells]] that is located in the posterior portion of the [[Human eye|eye]]. Because of the complex structure of the [[Capillary|capillaries]] that supply the retina with [[blood]], each person's retina is unique, making retinal scans an emerging authentication method.<ref>{{Cite book|last1=Vora|first1=Rita A.|last2=Bharadi|first2=V A|last3=Kekre|first3=H B|title=2012 International Conference on Communication, Information & Computing Technology (ICCICT) |chapter=Retinal scan recognition using wavelet energy entropy |date=Oct 2012|chapter-url=http://dx.doi.org/10.1109/iccict.2012.6398120|pages=1–6 |publisher=IEEE|doi=10.1109/iccict.2012.6398120|isbn=978-1-4577-2078-9|s2cid=17203983 }}</ref> The network of [[blood vessel]]s in the retina is not entirely genetically determined and thus even [[identical twin]]s do not share a similar pattern.

Although retinal patterns may be altered in cases of [[diabetes]], [[glaucoma]] or retinal degenerative disorders, the retina typically remains unchanged from birth until death. Due to its unique and unchanging nature, the retina appears to be the most precise and reliable biometric, aside from DNA.<ref>Retina and Iris Scans.  Encyclopedia of Espionage, Intelligence, and Security. Copyright © 2004 by The Gale Group, Inc.</ref> The National Center for State Courts estimate that retinal scanning has an error rate of one in ten million.<ref>{{Cite book|title = Understanding Public Perceptions: Trust and Engagement in ICT-mediated Services|last1 = Cofta|first1 = Piotr|publisher = International Engineering Consortium|year = 2008|isbn = 9781931695954|page = 153|last2 = Furnell|first2 = Steven|url = https://books.google.com/books?id=mFv49vJb6E0C&pg=PA153|access-date = 29 September 2014|chapter = Use of Biometric Data|chapter-url = https://books.google.com/books?id=mFv49vJb6E0C&pg=PA143|quote = The error rate for fingerprint identification can be as high as 1 in 500, whereas a retinal scan boasts an error rate of 1 in 10,000,000.}}</ref>

A retinal scan is performed by casting an unperceived beam of low-energy [[infrared light]] into a person’s eye as they look through the scanner's eyepiece. This beam of light traces a standardized path on the retina. Because retinal [[blood vessels]] absorb light more readily than the surrounding tissue, the amount of reflection varies during the scan. The pattern of variations is [[digitized]] and stored in a [[database]].<ref>[http://www.discoveriesinmedicine.com/Ra-Thy/Retinography.html Retinography: How Retinal Scanning Works.]   Retrieved on 2007-04-02.</ref>