The medical term for this condition is photokeratitis – literally sunburn of your cornea. At high altitude, light reflected off snow contains dangerous levels of UV radiation. Like sunburn, the effects are delayed. Climbers report painful burning, blurred vision and a sandy sensation on the eye starting 6-12 hours after exposure. It turns out that the best protection against snow blindness is a good pair of UVB-rated sunglasses with side shields. The best cure is to patch the eyes and let them heal themselves, which can happen as quickly as 24 hours. Interestingly hand-carved Inuit snow goggles are equally as effective as a pricey pair of Ray-Bans.
Answered by Dave Roos