This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Optics and refraction, Subject name: Ophthalmology
Contraindication of LASIK - 
Select and explain. 
A. >20 year, B. Keratoconus, C. Normal cornea, D. Myopia of - 8D
B: Keratoconus
Answer: B: Keratoconus 
Explanation: Patient selection criteria are:  Patients above 20 years of age,  Stable refraction for at least 12 months.  Motivated patient.  Absence of corneal pathology Reference : A K KHURANA OPHTALMOLOGY,Edition 4, Page-47