Photokeratitis

Source: Wikipedia, the free encyclopedia.
(Redirected from
Snow blindness
)
Photokeratitis
SpecialtyOphthalmology Edit this on Wikidata

Photokeratitis or ultraviolet keratitis is a painful eye condition caused by exposure of insufficiently protected eyes to the ultraviolet (UV) rays from either natural (e.g. intense direct or reflected sunlight) or artificial (e.g. the electric arc during welding) sources. Photokeratitis is akin to a sunburn of the cornea and conjunctiva.

The injury may be prevented by wearing eye protection that blocks most of the ultraviolet radiation, such as

welding goggles
with the proper filters, a welder's helmet, sunglasses rated for sufficient UV protection, or appropriate snow goggles. The condition is usually managed by removal from the source of ultraviolet radiation, covering the corneas, and administration of pain relief. Photokeratitis is known by a number of different terms including: snow blindness, arc eye, welder's flash, bake eyes, corneal flash burns, flash burns, niphablepsia, or keratoconjunctivitis photoelectrica.

Signs and symptoms

Common symptoms include pain, intense

constricted pupils
.

Cause

Any intense exposure to UV light can lead to photokeratitis.

UV rays increases by four percent.[7]

Diagnosis

Fluorescein dye staining will reveal damage to the cornea under ultraviolet light.[8]

Prevention

Snow goggles traditionally used by the Inuit

Photokeratitis can be prevented by using sunglasses or eye protection that transmits 5–10% of visible light and absorbs almost all UV rays. Additionally, these glasses should have large lenses and side shields to avoid incidental light exposure. Sunglasses should always be worn, even when the sky is overcast, as UV rays can pass through clouds.[9]

The

sinew.[11]

Polar bear cub with sun goggles, possibly to prevent snow blindness

In the event of missing sunglass lenses, emergency lenses can be made by cutting slits in dark fabric or tape folded back onto itself.[12] The SAS Survival Guide recommends blackening the skin underneath the eyes with charcoal (as the ancient Egyptians did) to avoid any further reflection.[13][14]

Treatment

The pain may be temporarily alleviated with anaesthetic

NSAID) eyedrops are widely used to lessen inflammation and eye pain, but have not been proven in rigorous trials. Systemic (oral) pain medication is given if discomfort is severe. Healing is usually rapid (24–72 hours) if the injury source is removed. Further injury should be avoided by isolation in a dark room, removing contact lenses, not rubbing the eyes, and wearing sunglasses until the symptoms improve.[5]

See also

References

  1. ^ "Arc eye – General Practice Notebook". 2007-03-25. Archived from the original on 2007-03-25. Retrieved 2012-02-07.
  2. ^ Porter, Daniel (February 16, 2019). "What is Photokeratitis — Including Snow Blindness?". American Academy of Ophthalmology. Retrieved November 22, 2019.
  3. ^ "Review of Photokeratitis: Corneal response to ultraviolet radiation (UVR) exposure*". The South African Optometrist. Retrieved 1 November 2021.
  4. ^ "A Review of Biological Effects and Potential Risks Associated with Ultraviolet Radiation as used in Dentistry". FDA, The US Bureau of Radiological Health. 1975. Retrieved 1 November 2021.
  5. ^ a b c Brozen, Reed; Christian Fromm (February 4, 2008). "Ultraviolet Keratitis". eMedicine. Retrieved November 19, 2008.
  6. ^ "Snow blindness". General Practice Notebook. Retrieved November 19, 2008.
  7. ^ "Sun Safety". University of California, Berkeley. April 2005. Retrieved November 19, 2008.
  8. ^ Reed Brozen (15 April 2011). "Ultraviolet Keratitis". Medscape.com. Retrieved 9 August 2012.
  9. ^ Butler, Frank Jr. "Base Camp MD – Guide to High Altitude Medicine". Archived from the original on October 5, 2014. Retrieved November 19, 2008.
  10. ^ Jessica Stewart (2021-12-17). "Indigenous People in Alaska Invented Snow Goggles Centuries Ago To Protect Eyes and Improve Vision".
  11. .
  12. ^ Henry, Jeff. Survive: Snow Country. p. 107.
  13. .
  14. ^ "Egyptian Make Up". King-tut.org.uk. 2007-05-29. Archived from the original on 2012-01-26. Retrieved 2012-02-07.
  15. ^ "Photokeratitis (Ultraviolet [UV] burn, Arc eye, Snow Blindness)". The College of Optometrists. April 4, 2018. Retrieved November 22, 2019.
  16. PMID 23118524
    .

External links