Editing Ultraviolet (section)

==Visibility==
Ultraviolet rays are not usable for normal human vision.
The [[Lens (vertebrate anatomy)|lens of the human eye]] and surgically implanted lens produced since 1986 blocks most radiation in the near UV wavelength range of 300–400&nbsp;nm; shorter wavelengths are blocked by the [[cornea]].<ref>{{cite journal |title=Violet and blue light blocking intraocular lenses: photoprotection versus photoreception|journal=British Journal of Ophthalmology |year=2006 |volume=90 |pages=784–792 |author=M A Mainster |pmc=1860240 |pmid=16714268 |doi=10.1136/bjo.2005.086553 |issue=6}}</ref> Humans also lack [[Cone cell|color receptor]] adaptations for ultraviolet rays. The [[photoreceptor cell|photoreceptors]] of the [[retina]] are sensitive to near-UV but the lens does not focus this light, causing UV light bulbs to look fuzzy.<ref name="LynchLivingston2001">{{cite book |last1=Lynch |first1=David K. |last2=Livingston |first2=William Charles |title=Color and Light in Nature |url=https://books.google.com/books?id=4Abp5FdhskAC&pg=PA231 |access-date=12 October 2013 |edition=2nd |year=2001 |publisher=[[Cambridge University Press]] |location=Cambridge |isbn=978-0-521-77504-5 |page=231 |quote=Limits of the eye's overall range of sensitivity extends from about 310 to 1050 nanometers|url-status=live |archive-url=https://web.archive.org/web/20131231214332/http://books.google.com/books?id=4Abp5FdhskAC&pg=PA231 |archive-date=31 December 2013}}</ref><ref name="Dash2009">{{cite book |last1=Dash |first1=Madhab Chandra|last2=Dash|first2=Satya Prakash|title=Fundamentals of Ecology 3E|url=https://books.google.com/books?id=7mW4-us4Yg8C&pg=PA213|access-date=18 October 2013|year=2009|publisher=Tata McGraw-Hill Education|isbn=978-1-259-08109-5|page=213|quote=Normally the human eye responds to light rays from 390 to 760 nm. This can be extended to a range of 310 to 1,050 nm under artificial conditions.|url-status=live|archive-url=https://web.archive.org/web/20131231214338/http://books.google.com/books?id=7mW4-us4Yg8C&pg=PA213|archive-date=31 December 2013}}</ref>
People lacking a lens (a condition known as [[aphakia]]) perceive near-UV as whitish-blue or whitish-violet.<ref name='hambling'>{{cite news |title=Let the light shine in |author=David Hambling |newspaper=The Guardian |date=29 May 2002 |url=https://www.theguardian.com/science/2002/may/30/medicalscience.research |access-date=2 January 2015 |url-status=live |archive-url=https://web.archive.org/web/20141123170913/http://www.theguardian.com/science/2002/may/30/medicalscience.research |archive-date=23 November 2014}}</ref>  Near-UV radiation is visible to insects, some mammals, and some [[Bird vision|birds]]. Birds have a fourth color receptor for ultraviolet rays; this, coupled with eye structures that transmit more UV gives smaller birds "true" UV vision.<ref>{{cite web|url=http://io9.gizmodo.com/want-ultraviolet-vision-youre-going-to-need-smaller-ey-1468759573 |website=Gizmodo |title=Want ultraviolet vision? You're going to need smaller eyes|first=Joseph|last=Bennington-Castro|date=22 November 2013 |url-status=live|archive-url=https://web.archive.org/web/20160507082220/http://io9.gizmodo.com/want-ultraviolet-vision-youre-going-to-need-smaller-ey-1468759573|archive-date=7 May 2016}}</ref><ref name="HuntCarvalho2009">{{cite journal|last1=Hunt|first1=D. M.|last2=Carvalho|first2=L. S.|last3=Cowing|first3=J. A.|last4=Davies|first4=W. L.|title=Evolution and spectral tuning of visual pigments in birds and mammals|journal=Philosophical Transactions of the Royal Society B: Biological Sciences|volume=364|issue=1531|year=2009|pages=2941–2955|issn=0962-8436|doi=10.1098/rstb.2009.0044 |doi-access=free |pmid=19720655|pmc=2781856}}</ref>
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