This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cornea, Subject name: Ophthalmology
[{'content': "KISA% is associated with- \nSelect and explain. \nA. Keratoconus, B. Keratoglobus, C. Hypermetropia with astigmatism, D. Terrien's marginal degeneration", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Keratoconus * The KISA index is used in cases of keratoconus and is derived using 4 indices:i) Central keratometry Kii) Inferior- Superior keratometry (I-S)iii) Astigmatism Index (AST)* It is calculated using videokeratograph device and it quantifies th degree of corneal astigmatism and the SRAX index which is expression of irregular astigmatism occurring in keratoconus.", 'role': 'assistant'}]