This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glaucoma, Subject name: Ophthalmology
The critical angle of cornea-air interface is: 
Select and explain. 
A. 36o, B. 46o, C. 56o, D. 66o
B: 46o
Answer: B: 46o 
Explanation: Cornea air interface is 46 degree.