Especially if you’re a novice skier, you’re probably far more worried about not crossing your skis and being able to slow yourself down before you hit someone or something than protecting your eyes from the sun. But goggles aren’t just for keeping the snow out of your eyes.

If you forego them, your eyes may feel like they’re on fire by the end of the day, and your vision may be blurry. If so, you may have photokeratitis, or sunburn of the eyes caused by UV rays. It’s also known as snow blindness.

Related: How to Avoid the Most Common Ski and Snowboard Injuries

It can happen while you’re skiing, hiking or even just spending hours outdoors making igloos or snowmen.

Snow reflects up to 80 percent of the sun's rays, and those rays can burn the thin surface layer of the corneas just as they can burn the skin, according to the American Academy of Pediatrics (AAP). If you don’t wear sunglasses or UV-blocking goggles while outdoors, especially at high altitudes (thinner air provides less protection from UV rays), your eyes are vulnerable.

It’s not just snow that reflects sunlight; water does, too, which is why it’s important to also wear sunglasses when you’re on the water. In 2012, CNN anchor Anderson Cooper suffered a case of photokeratitis after spending two hours on a boat in Portugal without sunglasses. He was temporarily blinded for 36 hours, said Cooper on his show, Anderson Live.

"I wake up in the middle of the night and it feels like my eyes are on fire, my eyeballs, and I think oh maybe I have sand in my eyes or something,” said Cooper. “I douse my eyes with water. Anyway, it turns out I have sunburned my eyeballs. I had no idea you could do this."

Related: 10 Foods to Eat for Eye Health

Symptoms of photokeratitis

As with regular sunburns, people don’t usually notice photokeratitis until well after damage has occurred, according to the American Academy of Ophthalmology (AAO). The longer you’re exposed to the UV rays, the more severe your symptoms will be. Symptoms include:

  • Pain
  • Redness
  • Blurriness
  • Tearing
  • Gritty feeling
  • Swelling
  • Sensitivity to bright light
  • Headache
  • Seeing halos
  • Small pupils
  • Eyelid twitching
  • Rarely, temporary vision loss

In rare cases, you may also experience temporary color changes in your vision, according to the AAO.

Related: How I Nearly Went Blind: Recognizing and Treating Retinal Detachment

Treatment and prevention

If you start experiencing symptoms, get out of the sun immediately. If you can’t, loosely cover your eyes with a scarf or sweater, advises the AAP.

Photokeratitis usually goes away on its own within a day or two. To help treat the symptoms, AAO recommends cold compresses, pain relievers and artificial tears. Avoid rubbing your eyes.

You can prevent snow blindness by wearing sunglasses or snow goggles that block 99 percent of UV rays, according to the AAO. These can protect you from dry, cold wind, too.

AAP recommends kids wear sunglasses that fit snugly, cover the entire area between the eyebrows and middle of the cheeks and wrap around toward the ears. They should be labeled as offering full UVA and UVB protection.

Related: How to Choose the Best Type of Sunglasses

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Muriel Vega is a writer with a passion for budget travel and staying safe while abroad. A Georgia State University graduate, she has over 6 years of editorial experience and has written for The Guardian, The Atlantic, The Billfold, among other outlets. In her free time, you can find her baking pies, playing with her two dogs and cat, or planning her next vacation. She spends way too much time on Twitter, one of her favorite social media channels. Her favorite safety tip: Make sure you have all the necessary shots before you go abroad.