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': 'All are causes of night blindness except: \nSelect and explain. \nA. Vitamin A deficiency, B. Oguchi disease, C. Myopia, D. Devics disease', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Devics disease', 'role': 'assistant'}]