Snow blindness, also called arc eye or photokeratitis, is a painful eye condition caused by overexposure to ultraviolet (UV) light. When too much UV light hits the transparent outer layer of your eyes, called the cornea, it essentially gives your cornea a sunburn.
Snow blindness symptoms can be disorienting. They include:
- pain in your eyes
- blurred vision
- temporary loss of vision
But snow blindness is easily treatable, and your eyes will heal quickly once you remove yourself from the UV rays and rest your eyes.
Snow has reflective qualities that send more UV rays into your eye — that’s how we get the term “snow blindness.” Water and white sand can also cause photokeratitis because they’re very reflective.
Severe cold temperatures and dryness can also play a part, making photokeratitis more common in higher elevations.
Photokeratitis is caused by natural or artificial overexposure to UV light. The “photo” part of the word means “light” and keratitis is an inflammation of your cornea.
Your cornea is the clear, dome-shaped tissue that covers your eye. Your cornea doesn’t contain blood vessels, so it needs tears to stay lubricated and healthy.
The outermost layer of the cornea is called the epithelium. It has thousands of nerve endings, making your cornea very sensitive to any damage or pain. When too much UV light hits your cornea, this sensitive outer layer becomes inflamed and irritated, causing a feeling of burning or itching.
Sunlight can cause photokeratitis. UV rays reflected off sand, snow, and water can burn your cornea and cause photokeratitis.
Light from blowtorches, sun lamps, and tanning booths can also cause inflammation of the cornea and lead to snow blindness. People who use welding equipment for a living are particularly prone to “welder’s flash” — another name for snow blindness.
Photokeratitis symptoms don’t always appear right away. Sometimes you won’t notice symptoms until several hours after your corneas have been damaged. Common symptoms include:
- pain and burning in your eyes
- feeling that something is in your eye and you can’t remove it
- sensitivity to light
- swollen, red eyelids
- watery eyes
- blurred vision
- exaggerated glare around indoor lights
Less often, snow blindness can cause temporary vision loss and temporary color changes in your vision.
Snow blindness usually goes away on its own once your corneas recover. Symptoms tend to resolve gradually over a day or two, according to the American Academy of Ophthalmology.
A doctor can confirm whether you have photokeratitis by examining your eyes for UV damage. There’s not much your doctor can do to treat photokeratitis. Resting your eyes away from UV light is the best way to encourage healing.
If you wear contact lenses, remove them until your symptoms have subsided. Don’t rub your eyes while you have symptoms of photokeratitis. Keratitis can be aggravated and even caused by contact lens use.
Topical pain-relieving drops shouldn’t be placed in your eye if you have snow blindness.
You may also consider:
- using a cold compress to soothe burning or eye pain
- staying indoors to rest eyes from UV light exposure
- keeping your corneas moisturized with artificial tears to encourage healing
- using OTC pain relievers, such as aspirin or acetaminophen, for pain relief
If your symptoms are getting worse after 24 hours, make an appointment with an eye doctor. Photokeratitis should heal quickly on its own. Worsening eye pain or continued loss of vision could indicate that you have another condition, such as:
Photokeratitis is mostly preventable by wearing sunglasses. Here are some tips for avoiding snow blindness:
- If you participate in water sports or snow sports, invest in quality, wraparound sunglasses with photochromic lenses.
- Wear sunglasses that block out 100 percent of UV rays whenever you plan to be outdoors for more than three hours at a time.
- Remember that reflective glare from sand, water, and snow can still harm your corneas even when the weather is overcast.
- Wear a wide-brimmed hat or visor if you’re outside for an extended period without your sunglasses.
Snow blindness symptoms usually go away within 48 hours. If it’s been that long and you still have symptoms, you should see an eye doctor to make sure you don’t have a different eye condition. Resting your eyes and staying inside are the best ways to speed healing of snow blindness.