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': 'Tobacco amblyopia could be associated with which of the following conditions: \nSelect and explain. \nA. Myopia, B. Vitamin B12 deficiency, C. Orbital cellulitis, D. Omega 6 fatty acid deficiency', 'role': 'user'}, {'content': "Answer: B \nExplanation: Tobacco amblyopia is a toxic optic neuropathy. It occurs primarily in middle-aged and elderly persons. People affected are often heavy smokers. The condition is characterised by painless, slowly progressive, cecocentral visual field defect and visual loss. Malnutrition and vitamin B12 deficiency contributes to this condition. Treatment with vitamin B12 injection can bring slow improvements along with smoking cessation. Ref: Walsh & Hoyt's Clinical Neuro-Ophthalmology, Frank Buon Walsh, 6th Edition, Page 210", 'role': 'assistant'}]