This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cornea and sclera, Subject name: Ophthalmology
Snow blindness is caused by 
Select and explain. 
A. UV rays, B. Infra red rays, C. Microwaves, D. Defect in mirrors
A: UV rays
Answer: A: UV rays 
Explanation: In snowblindness the cause and symptoms are similar to photophthalmia, for the ultraviolet rays are reflected from snow surfaces. Snow blindness, also called arc eye or photokeratitis, is a painful eye condition caused by overexposure to ultraviolet (UV) light. When too much UV light hits the transparent outer layer of your eyes, called the cornea, it essentially gives your cornea a sunburn. Snow blindness symptoms can be disorienting. Ref-Parson's; 21st edition; Pg No. 214