The term snow blindness is misleading because blindness is not the final outcome. Far from it. After treatment, the vision is restored to what it was before the episode. However, the condition can be temporarily debilitating.
Snow blindness also highlights how damaging ultraviolet rays are to humans. Human eyes are ten times more sensitive to ultraviolet (UV) light than the skin. Newly fallen snow reflects about 75 to 85 percent of ultraviolet light whereas water only reflects about 10 percent and grass one to two percent.
In the outdoors, snowboarders and skiers are susceptible to snow blindness unless their eyes are protected. These individuals are often engaged in activity at high altitudes where UV light is most intense because the earth's protective ozone layer is often thinner at such altitudes.
Besides athletes, those who work as arc welders and, sometimes, electricians are susceptible to what is called welder's flash because of their exposure to man-made light in the ultraviolet spectrum. Also susceptible to high UV exposure are those who go to tanning salons where UV lamps are used. And bright objects and white sand beaches are highly reflective and increase exposure to UV radiation by two times.
Symptoms of Snow Blindness
Symptoms of snow blindness include scratchy, sore and red eyes, tears, swollen eyelids, eye pain and blurry vision. The onset of symptoms is often eight to 12 hours from initial exposure. Backpacker Magazine offers tips on how to treat snow blindness. The symptoms of snow blindness usually go away in two to five days, leaving the eyes as they were before the episode.
Sunglasses that block 99 to 100 percent of UV rays are the key to preventing snow blindness. It's recommended that the sunglasses be wraparounds because protecting the sides of the eyes is important too. When buying sunglasses, make sure that its printed on the tag the percentage of UV protection they provide.
Those who have prescription sunglasses can purchase fit-over sunglasses that slip over their eyeglasses. Of course, those who visit an ophthalmologist can get good advice on the selection of sunglasses. Skiers, snowboarders and other outdoor types already have a wide selection of wraparound glasses available to them.
UV Exposure Increases Risk of Cataracts
Protecting the eyes from UV light not only protects individuals from the discomforting effects of snow blindness, but also helps to reduce the number of individuals with cataracts. According to the Skin Cancer Foundation, at least 10 percent of cataract cases can be attributed to overexposure to ultraviolet rays.
Sunglasses are not the only defense against ultraviolet rays. Wearing protective headwear can also help to reduce the number of cases of cancers of the eye. Carefully putting sunblock on the eyelids can help decrease the number of cases of cancer of the eyelids.
Those who want to know the predicted strength of UV radiation in a particular U.S. city tomorrow can look up the UV Index for a specific place. The index rates the strength of UV rays on a scale from 1 to 11. The UV Index project is a joint venture between the National Weather Service and the EPA.
Sources:
- "For Your Eyes: Sunlight And Your Eyes." skincaner.org. Accessed 9 February 2011.
- "UV Light & Vision." The Eye Digest. University of Illinois Eye & Ear Infirmary. agingeye.net. Accessed 10 February 2011.
Linda N. Riggins - I have written freelance articles for Victorian Homes,Catholic Digest, the Old Farmer's Almanac, Fine Homebuilding, the Christian Science ...
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