Snow blindness is caused by excessive exposure to UVB rays, often reflected off snow. Symptoms include eye pain, headaches, and temporary loss of vision. Prevention includes wearing protective eyewear. Inuit and other tribal peoples used ivory, bone, or wood to protect their eyes from the sun.
Snow blindness is a term used when referring to corneal burns caused by excessive exposure to ultraviolet B (UVB) rays. The scientific names for corneal burns are photokeratitis and ultraviolet keratitis. The term snow blindness comes from the fact that corneal burns are often caused by UVB rays reflecting off snow.
Symptoms of snow blindness usually include intense eye pain, severe headaches, a feeling of “grit” in the eye, swollen red eyelids, halos around the light, blurring, and temporary loss of vision. These symptoms usually first appear six to 12 hours after initial exposure to UV light. Treatment usually includes antibiotic eye drops, rest, and protecting your eyes thoroughly from further damage, usually by staying indoors or with eye patches. After exposure to ultraviolet B rays is stopped, the cornea begins to heal within a day, and near full recovery can be expected within 48 hours.
Snow blindness occurs more often at higher altitudes where UVB rays are much more intense. For every 1,000 feet (304 meters) of increase in altitude, the sun’s rays become 4% more powerful. Many ski resorts are at least 5,000 feet (1,524 meters) above sea level, so UVB rays are at least 20% more powerful than those at sea level. Because of this, skiers and hikers are more likely to damage their eyes if the proper goggles aren’t used.
Snow blindness is even more dangerous in some Arctic and Antarctic climates, where the sun shines 24 hours a day at certain times of the year. Inflammation and burning of the cornea can be caused by UVB rays reflecting off water or sand, but this is less common. Arc welders also sometimes face corneal burns, usually from not wearing protective eyewear. In these cases it is usually called an arc eye.
The best way to prevent snow blindness is to protect your eyes before exposure occurs. Those who enjoy the outdoors at altitude, in the snow, or both rely on sunglasses and goggles that block UVB rays. Protection against snow blindness dates back hundreds of years before the invention of modern protective eyewear. Inuit and other tribal peoples who lived in high altitudes and snowy regions often built their own protection against the sun using ivory, bone or wood. Their goggles covered their eyes completely except for small slits or holes. While these severely limited the wearer’s field of vision, they also filtered out most of the sun’s harmful rays.
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