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': 'If the axial length of the eyeball is changed by 1 mm then the power changes by – \nSelect and explain. \nA. 1 diopter, B. 2D, C. 3D, D. 4D', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 1 mm change in axial length leads to ametropia of 3D.', 'role': 'assistant'}]