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
[{'content': 'The most common cause of myopia is - \nSelect and explain. \nA. A-P diameter is increased, B. The thickness of lens is increased, C. The viscosity of squous humour is increased, D. The viscisity of vitous humour is increased', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Axial type of simple myopia may signify just a physiological variation in the length of the eyeball or it may be associated with precocious neurological growth during childhood. other causes are : Curvatural type Role of diet Role of genetics Theory of excessive near work Reference : A K KHURANA OPHTALMOLOGY,Edition 4, Page-33', 'role': 'assistant'}]