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
Most common cause diminision of vision in Peterygium is 
Select and explain. 
A. Obstruction of visual axis, B. Corneal perforation, C. Myopia, D. Astigmatism
D: Astigmatism
Answer: D: Astigmatism 
Explanation: Most common cause of diminision of vision in Peterygium is Astigmatism.