This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Glass workers cataract is caused by exposure to which of the following? 
Select and explain. 
A. Infrared rays, B. Ultraviolet rays, C. X - rays, D. Lead
A: Infrared rays
Answer: A: Infrared rays 
Explanation: Prolonged exposure to infrared rays can cause discoid posterior subcapsular opacity and is typically seen in people working in glass industry. Ref: A K Khurana, 2nd Edition, Page 195.