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Snow Blindness

 
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Snow blindness
 
 
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Snow blindness (also known as ultraviolet keratitis
Keratitis

Keratitis is a condition in which the eye's cornea, the front part of the eye, becomes inflamed. The condition is often marked by moderate to intense pain and usually involves impaired eyesight....
, photokeratitis or niphablepsia) is a painful eye condition, caused by exposure of unprotected eye
Eye

Eyes are Organ that detect light, and send signals along the optic nerve to the visual system and other areas of the brain. Complex optical systems with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system....
s to the ultraviolet
Ultraviolet

Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than x-rays, in the range 400 nanometer to 10 nm, and energies from 3 Electron volt to 124 eV....
 (UV) rays in bright sunlight
Sunlight

Sunlight, in the broad sense, is the total spectroscopy of the electromagnetic radiation given off by the Sun. On Earth, sunlight is Filter ed through the Earth's atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon....
 reflected
Reflection (physics)

Reflection is the change in direction of a wavefront at an wiktionary:interface between two differentmedium so that the wavefront returns into the medium from which it originated....
 from snow
Snow

Snow is a type of precipitation in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. The process of this precipitation is called snowfall....
 or ice
Ice

Ice is a solid phases of matter, usually crystalline solid, of a non-metallic substance that is liquid or gas at room temperature, such as ammonia ice or methane ice....
 or less commonly from sea or sand. This is especially a problem in polar regions and at high altitudes, as with every thousand feet (approximately 305 meters) of elevation (above sea level), the intensity of UV rays increases by four percent.

Snow blindness is akin to a sunburn
SunBurn

SunBurn is a regional event held in Florida. Although SunBurn has its roots in the annual Burning Man festival in Nevada, it is not an official Burning Man event, because the organizers of SunBurn do not condone the direction that the Burning Man Organization has taken over the years....
 of the cornea
Cornea

The cornea is the transparency front part of the eye that covers the Iris , pupil, and anterior chamber. Together with the cilliary muscles, the cornea reflects light, and as a result helps the eye to dilate, accounting for approximately two-thirds of the eye's total optical power....
 and conjunctiva
Conjunctiva

The conjunctiva is a clear mucous membrane consisting of cells and underlying basement membrane that covers the sclera and lines the inside of the eyelids....
, and may not be noticed for several hours after exposure.






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Encyclopedia


Snow blindness (also known as ultraviolet keratitis
Keratitis

Keratitis is a condition in which the eye's cornea, the front part of the eye, becomes inflamed. The condition is often marked by moderate to intense pain and usually involves impaired eyesight....
, photokeratitis or niphablepsia) is a painful eye condition, caused by exposure of unprotected eye
Eye

Eyes are Organ that detect light, and send signals along the optic nerve to the visual system and other areas of the brain. Complex optical systems with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system....
s to the ultraviolet
Ultraviolet

Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than x-rays, in the range 400 nanometer to 10 nm, and energies from 3 Electron volt to 124 eV....
 (UV) rays in bright sunlight
Sunlight

Sunlight, in the broad sense, is the total spectroscopy of the electromagnetic radiation given off by the Sun. On Earth, sunlight is Filter ed through the Earth's atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon....
 reflected
Reflection (physics)

Reflection is the change in direction of a wavefront at an wiktionary:interface between two differentmedium so that the wavefront returns into the medium from which it originated....
 from snow
Snow

Snow is a type of precipitation in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. The process of this precipitation is called snowfall....
 or ice
Ice

Ice is a solid phases of matter, usually crystalline solid, of a non-metallic substance that is liquid or gas at room temperature, such as ammonia ice or methane ice....
 or less commonly from sea or sand. This is especially a problem in polar regions and at high altitudes, as with every thousand feet (approximately 305 meters) of elevation (above sea level), the intensity of UV rays increases by four percent.

Snow blindness is akin to a sunburn
SunBurn

SunBurn is a regional event held in Florida. Although SunBurn has its roots in the annual Burning Man festival in Nevada, it is not an official Burning Man event, because the organizers of SunBurn do not condone the direction that the Burning Man Organization has taken over the years....
 of the cornea
Cornea

The cornea is the transparency front part of the eye that covers the Iris , pupil, and anterior chamber. Together with the cilliary muscles, the cornea reflects light, and as a result helps the eye to dilate, accounting for approximately two-thirds of the eye's total optical power....
 and conjunctiva
Conjunctiva

The conjunctiva is a clear mucous membrane consisting of cells and underlying basement membrane that covers the sclera and lines the inside of the eyelids....
, and may not be noticed for several hours after 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.

To prevent snow blindness, people who are at risk are recommended to use sunglasses that transmit 5-10% of visible light and absorb 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 filter through the clouds.

If snow blindness does occur, treatment consists of easing the pain with oral medication and cold wet compresses. Further injury should be avoided by removing contact lenses, not rubbing the eyes, and wearing sunglasses until the symptoms disappear completely. There is also an ointment
Ointment

An ointment is a viscous semisolid preparation used topically on a variety of body surfaces. These include the skin and the mucus membranes of the eye , vagina, anus, and nose....
 that significantly speeds up recovery.

In the event of lost or damaged sunglasses, emergency goggles
Goggles

Goggles or safety glasses are forms of Eye protection that usually enclose or protect the eye area in order to prevent particulates, water or chemicals from striking the eyes....
 can be made by cutting slits in dark fabric or tape folded back onto itself. The SAS
Special Air Service

The Special Air Service is a special forces regiment within the British Army which has served as a model for the special forces of other countries....
 Survival Guide recommends blackening the skin underneath the eyes with charcoal
Charcoal

Charcoal is the blackish residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances....
 to avoid any further reflection.

Inuit

Inuit Goggles
The Inuit
Inuit

Inuit is a general term for a group of culturally similar indigenous peoples inhabiting the Arctic regions of Canada, Greenland, Russia and Alaska, United States....
 carved goggles
Goggles

Goggles or safety glasses are forms of Eye protection that usually enclose or protect the eye area in order to prevent particulates, water or chemicals from striking the eyes....
 from caribou antler
Antler

Antlers are the usually large and complex horn -like appendages of most deer species, mostly worn by males in true horns. Each antler grows from an attachment point on the skull called a pedicle....
s 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, diminishing the amount of UV rays that get through. The goggles were held to the head by a cord made of caribou sinew.

See also

  • Albedo
    Albedo

    The albedo of an object is the extent to which it diffusely reflects light from the Sun. It is therefore a more specific form of the term reflectivity....
  • Glare (vision)
    Glare (vision)

    Glare is difficulty seeing in the presence of bright light such as direct or reflected sunlight or artificial light such as car headlamps at night....
  • Over-illumination
    Over-illumination

    Over-illumination is the presence of lighting intensity beyond that required for a specified activity. Over-illumination was commonly ignored between 1950 and 1995, especially in office and retail environments; only since then has the interior design community begun to reconsider this practice....


  • Arc eye
    Arc eye

    Arc eye, also known as welder's flash, bake eyes, corneal flash burns, or flash burns, is a painful ocular condition sometimes experienced by welders who have failed to use adequate Welding helmet....
    , a similar condition sometimes experienced by welder
    Welder

    A welder is a tradesman who specialises in welding materials together. The materials to be joined can be metals or varieties of plastic or polymer....
    s.


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