The sun’s UV rays can harm your skin — and your eyes. Global Rescue medical experts provide advice to help skiers, climbers and sailors avoid photokeratitis, a painful condition also known as snow blindness or sunburn of the eye.

The view may be gorgeous, but please keep those goggles or sunglasses on at all times.

Snow blindness, a painful eye condition caused by overexposure to the sun’s ultraviolet (UV) rays, can happen in a matter of minutes.

Remember racer Doug Swingley, who removed his goggles during the 2004 Iditarod sled dog race for a quick look ahead? His vision became extremely blurry, according to the American Academy of Ophthalmology, and he had to leave the race to receive medical treatment.

Snow blindness doesn’t occur only in the polar region. It can affect anyone enjoying snow sports — hiking, snowshoeing, skiing and snowmobiling — in the bright sun.

A Sunburn of the Eye

There’s a reason you squint in the sun. It’s your body’s way of naturally protecting itself.

“The sun’s ultraviolet rays can burn the cornea of the eye, causing irritation, pain and blurred vision,” said Dave Keaveny, a medical operations specialist at Global Rescue.

With the name — snow blindness — you would think those most at risk are the adventurer travelers outside in snowy terrain, across a snowfield or in a high-altitude winter environment without proper eye protection. And you’d be right; fresh snow reflects about 80% of UV radiation.

Water and white sand are also reflective, so spending a day on the ocean or lake also puts you at risk. Your eyes are prone to sunburn from a direct hit from the sun combined with the reflection of the sun from the water or sand.

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Location and Season Make a Difference

Of course, you’ll want to protect your eyes at noon during the summer, when solar UV light is at its strongest. But where you are located on the earth matters as well.

According to a study in the Journal of Postgraduate Medicine, the Northern hemisphere is 1.7% further away from the sun in the summer than the Southern hemisphere, and the intensity of UV light decreases approximately 7%. Quebec in the summer, for example, will have a lower risk of snow blindness than Madagascar in the summer.

High altitudes also make a difference because there is less distance for the light to travel and the thinner atmosphere filters less UV radiation. According to the World Health Organization, UV levels increase by 10% to 12% with every 1,000 meters increase in altitude. Cloud cover, latitude and ozone levels are additional factors determining how much UV light reaches your eyes.

“Skiers in New England can get away with skiing with just sunglasses in fair conditions on a sunny day,” Keaveny said. “Once the wind kicks up stirring snow and other particles, goggles will be needed to protect your eyes from micro-debris damage as well as harmful UV rays. Goggles provide better protection against UV light, wind and debris.”

Symptoms and Recovery

Just like a skin sunburn, by the time you notice the damage to your eyes, it’s too late. According to The College of Optometrists in London, the eyes become red, painful, watery and sensitive to light 6 to 12 hours after exposure. Additional snow blindness symptoms include:

  • Burning eyes
  • A gritty feeling, like there is sand in your eye
  • Blurred vision
  • Red and swollen eyelids
  • Headaches
  • Glare and halos around lights

Fortunately, most cases of snow blindness are short lived. The symptoms are caused by temporary damage to the cells on the surface of the eye. If there is vision loss, it typically resolves in 24 to 72 hours. If it doesn’t, contact your doctor immediately.

To aid recovery, a doctor may prescribe eye drops or pain relief medication to make the eyes more comfortable while they heal. A doctor may also recommend:

  • Staying indoors to let your eyes heal before going back outside
  • Keeping eyes well moistened with artificial tears
  • Placing a cool, damp washcloth over closed eyes
  • Removing contact lenses 

An Ounce of Prevention

Alaska’s indigenous people knew the dangers of the sun. In the Smithsonian, you’ll see snow goggles made out of a piece of bone or wood with a strip cut into the center to reduce glare and protect eyes from injury. Today, outdoor adventurers can stop by a sporting goods store to purchase full coverage, mirror-coated sunglasses, glacier goggles with polarized lenses or tight-fitting snow goggles.

Here are a few additional suggestions to keep your eyes safe from snow blindness:

  • If you participate in water or snow sports, invest in quality, wraparound sunglasses with photochromic lenses (lenses that darken upon exposure to light).
  • Wear sunglasses that block out 100% of UV rays whenever you plan to be outdoors for more than three hours at a time.
  • Remember reflective glare from sand, water and snow can still harm your corneas even when the weather is overcast.

[Related Reading: Snowblind in the Himalaya]

How Global Rescue Can Help

Traveling to a sun drenched or snow-covered location? Sign up for a travel protection services membership. Whether you are on the top of Aconcagua or in the middle of the Indian Ocean, you’ll have access to 24/7/365 medical advisory services, field rescue from the point of injury, and medical evacuation to the nearest hospital or home hospital of choice.

And even if you’re skiing at your local mountain, Global Rescue’s memberships now include Local Field Rescue services within 100 miles of your home.