Impaired vision or temporary blindness caused by sunlight reflected from snow surfaces. The medical name is niphablepsia. “Symptoms of snow blindness are a gritty sensation under the eyelids, excessive watering, double vision. First aid is to place the casualty in the dark or bandage the eyes; application of cool compresses alleviates pain. Most cases will recover in 18 hours without medical treatment”(from Glossary of Arctic and Subarctic Terms 1955).