Altitude changes everything--your breathing, your pace, and where on your body you need to be concerned about sunburn. Snow blindness, or sunburn on the surface of the eyes, occurs primarily at high altitudes where strong ultraviolet rays from above combine with those reflected off snow to burn tiny blisters on the corneas of unprotected eyes. Like any sunburn, the effect isn't felt until hours after exposure. With a mild case, your eyes will be teary and bloodshot. With a more severe one, your eyes will feel as if they're full of sand and may even swell shut. The corneas typically heal in 12 to 48 hours, and though painful, snow blindness rarely results in permanent eye damage.
Prevent Snow Blindness
- Wear wraparound sunglasses or glacier glasses, which have darker lenses, greater visible light filtration, and side covers. Keep them on even in overcast conditions, as UV rays can burn through thin clouds.
- If you lose your glasses, make emergency "goggles" by cutting two horizontal slits in a piece of duct tape folded back onto itself; secure with tape.
Treat Snow Blindness
- Remove contact lenses and avoid rubbing your eyes.
- Apply cool, wet compresses to help ease the burn, or take an oral pain medication like ibuprofen.
- Cover both eyes with half-inch-thick pads of soft cloth or gauze bandages to protect them from light and prevent irritation from eyelid movement.
- Check the injury at half-day intervals. When you can keep your eyes open comfortably, remove the dressing. Wear sunglasses whenever you are outside until your symptoms disappear completely.
- It's best to let your eyes heal before continuing your trip, but if conditions won't allow for extra days, your hiking partner should lead you slowly down the trail.