| What it is | UV sunburn of the cornea |
| Cause | UV glare off snow/ice; high altitude |
| Symptoms | Gritty, painful, watering eyes; blurred vision |
| Prevent with | UV/glacier glasses with side shields |
Snow blindness (photokeratitis) is a painful, temporary sunburn of the cornea caused by intense ultraviolet light, especially UV reflected off snow, ice, or water at altitude. Symptoms — gritty, watering, painful eyes and blurred vision — appear hours after exposure. It’s prevented entirely by wearing UV-blocking sunglasses or glacier glasses with side protection.
This is general educational information, not medical advice.
Prevention
Always wear UV-blocking glasses on snow — part of broader sun protection; risk spikes in a whiteout and at altitude.
Frequently asked questions
What is snow blindness?
Snow blindness, or photokeratitis, is essentially a sunburn of the eye's surface (cornea) from overexposure to ultraviolet light. It's common in snowy, icy, or high-altitude environments where UV reflecting off snow dramatically increases exposure. Symptoms typically appear several hours after the exposure.
What are the symptoms of snow blindness?
Eyes that feel gritty or like they have sand in them, pain, redness, excessive watering, sensitivity to light, blurred vision, and sometimes temporary vision loss. It usually develops 6–12 hours after UV exposure and resolves within a day or two as the cornea heals.
How do you prevent and treat snow blindness?
Prevent it by always wearing sunglasses or glacier glasses that block UV, ideally with side shields, on snow and at altitude — even in overcast conditions. To treat it, get out of the light, rest the eyes in a dark space, apply cool compresses, avoid rubbing, and remove contact lenses; it typically heals on its own, but severe or persistent cases need medical attention.
Sources
- UV eye safety — CDC
- Photokeratitis — Wilderness Medical Society