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
Munsen sign is seen in: March 2013 (h) 
Select and explain. 
A. Corneal dystrophy, B. Perforated corneal ulcer, C. Keratoconus, D. Marfan syndrome
C: Keratoconus
Answer: C: Keratoconus 
Explanation: Ans. C i.e. Keratoconus Keratoconus Protrusion of central pa of cornea with thinning, Corneal nerves are visible, Associated features: - Munsen's sign, - Fleischer sign