Photokeratitis: Difference between revisions

Any intense exposure to UV light can lead to photokeratitis.<ref>{{Cite web|url=https://www.aao.org/eye-health/diseases/photokeratitis-snow-blindness|title=What is Photokeratitis — Including Snow Blindness?|last=Porter|first=Daniel|date=February 16, 2019|website=American Academy of Ophthalmology|access-date=November 22, 2019}}</ref> In 2010, the Department of Optometry at the Dublin Institute of Technology published that the threshold for photokeratitis is 0.12 J/m².<ref>{{Cite web|url=https://www.avehjournal.org/index.php/aveh/article/download/137/106 | title=Review of Photokeratitis: Corneal response to ultraviolet radiation (UVR) exposure*| publisher= The South African Optometrist | access-date=1 November 2021}}</ref> (Prior to this, in 1975, the Division of Biological Effects at the US Bureau of Radiological Health had published that the human threshold for photokeratitis is 50 J/m².<ref>{{Cite web|url=https://books.google.com/books?id=lzhcL6PiXgIC&dq=threshold&pg=PA4 | title=A Review of Biological Effects and Potential Risks Associated with Ultraviolet Radiation as used in Dentistry | year=1975 | publisher= FDA, The US Bureau of Radiological Health | access-date=1 November 2021}}</ref>) Common causes include [[welderweld]]sing whowith have failedfailure to use adequate eye protection such as an appropriate welding helmet or welding goggles. This is termed ''arc eye'', while photokeratitis caused by exposure to sunlight reflected from ice and snow, particularly at elevation, is commonly called ''snow blindness''.<ref name="eMedicine" /> It can also occur due to using [[tanning beds]] without proper eyewear. Natural sources include bright [[sunlight]] [[Reflection (physics)|reflected]] from [[snow]] or [[ice]] or, less commonly, from sea or sand.<ref name="gpn">{{cite web|url=http://www.gpnotebook.co.uk/simplepage.cfm?ID=-268042203|title=Snow blindness|publisher=General Practice Notebook|access-date=November 19, 2008}}</ref> Fresh snow reflects about 80% of the UV radiation compared to a dry, sandy [[beach]] (15%) or [[sea foam]] (25%). This is especially a problem in [[polar regions]] and at high altitudes,<ref name="eMedicine">{{cite web|url=http://www.emedicine.com/emerg/topic759.htm|title=Ultraviolet Keratitis|last=Brozen |first=Reed |author2=Christian Fromm |date=February 4, 2008|publisher=eMedicine|access-date=November 19, 2008}}</ref> as with about every {{cvt|300|m|ft|sigfig=1}} of elevation ([[Height above sea level|above sea level]]), the intensity of [[UV rays]] increases by four percent.<ref name="berkeley">{{cite web|url=http://www.uhs.berkeley.edu/home/healthtopics/sunsafety.shtml|title=Sun Safety|date=April 2005|publisher=University of California, Berkeley|access-date=November 19, 2008}}</ref>