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
[{'content': 'True about keratoconus –a) ↑ curvature of cornea b) Astigmatismc) K.F. ring seend) Thick corneae) Soft contact lens used \nSelect and explain. \nA. ab, B. a, C. ad, D. bc', 'role': 'user'}, {'content': "Answer: A \nExplanation: Some guides have also given option c as the answer, which is incorrect.\nSome confusion exists between Fleisher rings and kisser- Fleischer (KF) ring. Kayser- Fleischer(KF) rings are caused by copper deposits and are indicative of Wilson's disease, whereas Fleischer rings are caused by iron deposits and are indicative of keratoconus.\nCornea is thin (not thick).\nRigid gas permeable contact lenses (not soft contact lenses) are used.", 'role': 'assistant'}]