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': 'Sudden increase in blood sugar in a diabetic causes \nSelect and explain. \nA. Myopia, B. Hypermetropia, C. Presbyopia, D. Anisometropia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Myopia', 'role': 'assistant'}]