There are ways to prevent snow blindness, of course. The most effective is to buy a good pair of sunglasses or goggles which will eliminate all the ultraviolet light—and wear them constantly. It is as simple as that.
When you buy sunglasses, though, keep in mind that the darkness of the glasses has no bearing on their own capacity to filter out ultraviolet light. One of the better makes, American Optical's Rose Smoke lens, is not particularly dark, one reason for this being that the dye used to filter out ultraviolet is invisible.
A fairly dark dye in the same lens reduces glare by about 80%, thus eliminating eyestrain, headache and other after-ski symptoms of overexposed eyes. A good pair of glasses should also be much larger than ordinary spectacles and fit fairly close to the face. Goggles make better wind screen, but they tend to fog up when they cut off circulation of air around the eye.
In either case, a good pair of sunglasses will point up the texture and contour of the snow. They will relax you and, if you wear them regularly on the slopes, you will probably avoid the perils of snow blindness.