Snow blindness 240096 225306503 2008-07-13T00:23:30Z Arcadian 104523 infobox {{otheruses3|Snowblind}} {{Infobox_Disease | Name = {{PAGENAME}} | Image = | Caption = | DiseasesDB = 31147 | ICD10 = {{ICD10|H|16|1|h|15}} | ICD9 = {{ICD9|370.24}} | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = emerg | eMedicineTopic = 759 | MeshID = | }} '''Snow blindness''' (Niphablepsia) is a painful condition, typically a [[keratitis]], caused by exposure of unprotected [[eye]]s to the [[ultraviolet]] (UV) rays in bright [[sunlight]] [[Reflection (physics)|reflected]] from [[snow]] or [[ice]]. This is especially a problem in [[polar regions]] and at high altitudes, as with every thousand feet (approximately 305 meters) increase in elevation, the intensity of [[UV rays]] goes up five percent. The problem is also related to the condition [[arc eye]] sometimes experienced by [[welder]]s. Snow blindness is akin to a [[sunburn]] of the [[cornea]] and [[conjunctiva]], and may not be noticed for several hours from exposure. Symptoms can run the gamut from eyes being bloodshot and teary to increased pain, feeling gritty and swelling shut. In very severe cases, snow blindness can cause permanent vision loss. The [[Inuit]] carved [[goggles]] from [[caribou]] [[antler]] to help prevent snow blindness. The goggles were curved to fit the user's face and had a large groove cut in the back to allow for the nose. A long thin slit was cut through the goggles to allow in a small amount of light. The goggles were held to the head by a cord made of caribou [[sinew]]. [[Image:Inuit Goggles.jpg|right|thumb|Traditional Inuit goggles used to combat snow blindness]] ==Prevention== When [[trekking]], [[mountaineering]] or [[skiing]], [[sunglasses]] that offer the following are frequently recommended: * 99-100% UV absorption * [[Polycarbonate]] or CR-39 lens * 5-10% visible light transmittance * Large lenses that fit close to the face and cover the whole eye * Wraparound, side-shielded, or dark-lensed 'glacier' [[glasses]] to prevent incidental light exposure * Wear even when the sky is overcast, as [[UV rays]] can still filter through [[clouds]] * In the event of lost or damaged sunglasses, make emergency [[goggles]] by cutting slits in dark fabric or tape folded back onto itself ==Treatment== {{howto}} Following these guidelines will allow the pain and symptoms of snow blindness to disappear as the [[cornea]] heals: * Avoid rubbing eyes and remove [[contact lenses]] * Administer an oral pain medication such as [[ibuprofen]] * Cover eyes with soft thick cloth pads or [[gauze]] bandages to prevent irritation from eyelid movement and protect from light; rest in a dark room if possible * Apply cold wet compresses to ease burning sensations * Check injury at half-day intervals; remove [[Dressing (medical)|dressing]] when eyes can remain open comfortably * Wear [[sunglasses]] outside until symptoms completely disappear ==See also== *[[Albedo]] *[[Glare (vision)]] *[[Over-illumination]] *[[Winter sport]] *[[Sunglasses]] ==External links== * [http://www.basecampmd.com/expguide/snowblind.shtml Everest Base Camp Clinic - Eye Concerns at Altitude] * [http://www.mounteverest.net/expguide/snowblind.htm Mount Everest.net - Snow Blindness] * [http://www.gpnotebook.co.uk/cache/-268042203.htm General Practice Notebook - Snow Blindness] * [http://www.sherpatrek.com/pemas_stories/pemas-snow-blind.php An Experience of Snow Blindness] * [http://www.athropolis.com/arctic-facts/fact-goggles.htm Historical Snow Goggles] {{Eye pathology}} [[Category:Blindness]] [[Category:Ophthalmology]] [[Category:Mountaineering]] [[Category:Snow]] [[bg:Снежна слепота]] [[de:Schneeblindheit]] [[no:Snøblindhet]] [[pl:Ślepota śnieżna]] [[pt:Cegueira da neve]] [[fi:Lumisokeus]] [[sv:Snöblindhet]] [[zh:雪盲症]]