Snow blindness is caused by -

Photophthalmia refers to occurrence of multipleepithelial erosions due to exposure to ultraviolet rayshaving a wavelength of 290-311 mm. It occurs in thefollowing conditions:1. Exposure to naked arc light as in industrial weldingand cinema operators2. Exposure to bright light of a sho circuit3. Snow blindness due to reflected ultraviolet raysfrom the snow surface REF:Comprehensive ophthalmology,AK Khurana,4th edition,pg no.507.