Photokeratitis

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Photokeratitis
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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.

Contents

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 tears, eyelid twitching, discomfort from bright light, [1] and constricted pupils.

Cause

Any intense exposure to UV light can lead to photokeratitis. [2] In 2010, the Department of Optometry at the Dublin Institute of Technology published that the threshold for photokeratitis is 0.12 J/m2. [3] (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. [4] ) Common causes include welding with failure 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. [5] It can also occur due to using tanning beds without proper eyewear. Natural sources include bright sunlight reflected from snow or ice or, less commonly, from sea or sand. [6] 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, [5] as with about every 300 m (1,000 ft) of elevation (above sea level), the intensity of 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 Inuit snow goggles.jpg
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 Inuit, Yupik, and other Arctic peoples have carved snow goggles from materials such as driftwood or caribou antlers to help prevent snow blindness for millennia. [10] Curved to fit the user's face with a large groove cut in the back to allow for the nose, the goggles allow in a small amount of light through a long thin slit cut along their length. The goggles are held to the head by a cord made of caribou sinew. [11]

Polar bear cub with sun goggles, possibly to prevent snow blindness Polar Bear cub with sunglasses.jpg
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 eye drops for the examination; however, they are not used for continued treatment, [15] as anaesthesia of the eye interferes with corneal healing, and may lead to corneal ulceration and even loss of the eye. [16] Cool, wet compresses over the eyes and artificial tears may help local symptoms when the feeling returns. Nonsteroidal anti-inflammatory drug (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

Related Research Articles

<span class="mw-page-title-main">Ultraviolet</span> Form of electromagnetic radiation

Ultraviolet (UV) is a form of electromagnetic radiation with wavelength shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs; Cherenkov radiation; and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights.

<span class="mw-page-title-main">Electromagnetic radiation and health</span> Aspect of public health

Electromagnetic radiation can be classified into two types: ionizing radiation and non-ionizing radiation, based on the capability of a single photon with more than 10 eV energy to ionize atoms or break chemical bonds. Extreme ultraviolet and higher frequencies, such as X-rays or gamma rays are ionizing, and these pose their own special hazards: see radiation poisoning.

<span class="mw-page-title-main">Glasses</span> Form of vision aid

Glasses, also known as eyeglasses or spectacles, are vision eyewear with clear or tinted lenses mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms, known as temples or temple pieces, that rest over the ears.

<span class="mw-page-title-main">Sunglasses</span> Eyewear for protecting against bright light

Sunglasses or sun glasses are a form of protective eyewear designed primarily to prevent bright sunlight and high-energy visible light from damaging or discomforting the eyes. They can sometimes also function as a visual aid, as variously termed spectacles or glasses exist, featuring lenses that are colored, polarized or darkened. In the early 20th century, they were also known as sun cheaters.

<span class="mw-page-title-main">Pterygium (eye)</span> Pinkish, triangular tissue growth on the cornea of the eye

A pterygium of the eye is a pinkish, roughly triangular tissue growth of the conjunctiva onto the cornea of the eye. It typically starts on the cornea near the nose. It may slowly grow but rarely grows so large that it covers the pupil and impairs vision. Often both eyes are involved.

<span class="mw-page-title-main">Keratitis</span> Medical condition

Keratitis is a condition in which the eye's cornea, the clear dome on the front surface of the eye, becomes inflamed. The condition is often marked by moderate to intense pain and usually involves any of the following symptoms: pain, impaired eyesight, photophobia, red eye and a 'gritty' sensation. Diagnosis of infectious keratitis is usually made clinically based on the signs and symptoms as well as eye examination, but corneal scrapings may be obtained and evaluated using microbiological culture or other testing to identify the causative pathogen.

<span class="mw-page-title-main">Goggles</span> Forms of protective eyewear that do not enclose the nose

Goggles, or safety glasses, are forms of protective eyewear that usually enclose or protect the area surrounding the eye in order to prevent particulates, water or chemicals from striking the eyes. They are used in chemistry laboratories and in woodworking. They are often used in snow sports as well, and in swimming. Goggles are often worn when using power tools such as drills or chainsaws to prevent flying particles from damaging the eyes. Many types of goggles are available as prescription goggles for those with vision problems.

<span class="mw-page-title-main">Red eye (medicine)</span> Eye that appears red due to illness or injury

A red eye is an eye that appears red due to illness or injury. It is usually injection and prominence of the superficial blood vessels of the conjunctiva, which may be caused by disorders of these or adjacent structures. Conjunctivitis and subconjunctival hemorrhage are two of the less serious but more common causes.

Keratoconjunctivitis is inflammation ("-itis") of the cornea and conjunctiva.

<span class="mw-page-title-main">Eye protection</span> Protective gear for the eyes

Eye protection is protective gear for the eyes, and sometimes face, designed to reduce the risk of injury. Examples of risks requiring eye protection can include: impact from particles or debris, light or radiation, wind blast, heat, sea spray or impact from some type of ball or puck used in sports.

<span class="mw-page-title-main">Corneal abrasion</span> Scratch to the surface of the cornea of the eye

Corneal abrasion is a scratch to the surface of the cornea of the eye. Symptoms include pain, redness, light sensitivity, and a feeling like a foreign body is in the eye. Most people recover completely within three days.

<span class="mw-page-title-main">Corneal cross-linking</span> Surgical procedure

Corneal cross-linking (CXL) with riboflavin (vitamin B2) and UV-A light is a surgical treatment for corneal ectasia such as keratoconus, PMD, and post-LASIK ectasia.

<i>Acanthamoeba</i> keratitis Eye infection caused by a protist

Acanthamoeba keratitis (AK) is a rare disease in which amoebae of the genus Acanthamoeba invade the clear portion of the front (cornea) of the eye. It affects roughly 100 people in the United States each year. Acanthamoeba are protozoa found nearly ubiquitously in soil and water and can cause infections of the skin, eyes, and central nervous system.

Fungal keratitis is a fungal infection of the cornea, which can lead to blindness. It generally presents with a red, painful eye and blurred vision. There is also increased sensitivity to light, and excessive tears or discharge.

<span class="mw-page-title-main">Welding helmet</span> Helmet that protects eyes during welding

A welding helmet is a type of personal protective equipment used in performing certain types of welding to protect the eyes, face, and neck from flash burn, sparks, infrared and ultraviolet light, and intense heat. The modern welding helmet used today was first introduced in 1937 by Willson Products.

<span class="mw-page-title-main">Corneal ulcer</span> Medical condition of the eye

Corneal ulcer, also called keratitis, is an inflammatory or, more seriously, infective condition of the cornea involving disruption of its epithelial layer with involvement of the corneal stroma. It is a common condition in humans particularly in the tropics and in farming. In developing countries, children afflicted by vitamin A deficiency are at high risk for corneal ulcer and may become blind in both eyes persisting throughout life. In ophthalmology, a corneal ulcer usually refers to having an infection, while the term corneal abrasion refers more to a scratch injury.

<span class="mw-page-title-main">Sunburn</span> Burning of the skin by the suns radiation

Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun. Common symptoms in humans and other animals include red or reddish skin that is hot to the touch or painful, general fatigue, and mild dizziness. Other symptoms include blistering, peeling skin, swelling, itching, and nausea. Excessive UV radiation is the leading cause of (primarily) non-malignant skin tumors, which in extreme cases can be life-threatening. Sunburn is an inflammatory response in the tissue triggered by direct DNA damage by UV radiation. When the cells' DNA is overly damaged by UV radiation, type I cell-death is triggered and the tissue is replaced.

<span class="mw-page-title-main">Glassblower's cataract</span> Form of cataract due to an occupational exposure

Glassblower's cataracts are a form of cataract due to an occupational exposure. They are formed by many years or decades of exposure to infrared radiation while working in the occupation of glass blowing, or working close to hot or molten metals such with metal foundry workers or blacksmiths. Glassblower's cataracts are due to chronic exposure to infrared radiation emitted due to the extreme heating of glass or molten metal. The infrared radiation is absorbed by the iris and lens of the eye. This causes cataracts after decades of exposure. This condition may be prevented by wearing protective glasses while practicing these occupations.

Photophthalmia is ophthalmia or inflammation of the eye, especially of the cornea and conjunctiva due to exposure to intense light of short wavelength, as in snow blindness.

Exposure keratopathy is medical condition affecting the cornea of eyes. It can lead to corneal ulceration and permanent loss of vision due to corneal opacity.

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. 1 2 3 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. Mogens Norn (1996). Eskimo Snow Goggles in Danish and Greenlandic Museums, Their Protective and Optical Properties. Museum Tusculanum Press. pp. 3–. ISBN   978-87-635-1233-6.
  12. Henry, Jeff. Survive: Snow Country. p. 107.
  13. Wiseman, John (2004). "Climate & Terrain". SAS Survival Guide: How to survive in the wild, in any climate on land or at sea. Harper Collins. p. 45. ISBN   0-00-718330-5.
  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. Khakshoor, Hamid (October 2012). "Anesthetic keratopathy presenting as bilateral Mooren-like ulcers". Clinical Ophthalmology. 6: 1719–1722. doi: 10.2147/OPTH.S36611 . PMC   3484722 . PMID   23118524.