Your eyes are also sensitive to overexposure of UV radiation. UV-B is partly absorbed by the cornea. UV-A passes through the cornea and with time and overexposure may contribute to the formation of cataracts. Snow reflects up to 85% of the incident UV radiation. This additional amount of absorption of reflected UV-B radiation by the cornea can result in snow blindness -- a sun burning of the eye. Sunglasses screenout 99% of the UV-A and UV-B radiation reaching your eyes.