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': 'Shoening of 2 mm of axial lengsth of eye ball causes - \nSelect and explain. \nA. 3D myopia, B. 6D myopia, C. 3D hypermetropia, D. 6D hypermetropia', 'role': 'user'}, {'content': 'Answer: D \nExplanation: 1 mm change in axial length leads to ametropia of 3d. For example 1 mm shoenign an axial length causes hypermetropia of 3D. Reference :Khurana 7th edition,page28', 'role': 'assistant'}]