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
The most common cause of myopia is - 
Select and explain. 
A. 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
A: A-P diameter is increased
Answer: A: A-P diameter is increased 
Explanation: 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