This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glaucoma, Subject name: Ophthalmology
[{'content': 'A patient on anti-epileptic drugs now complains of progressive B/L constriction of visual fields. Pt is on which drug? \nSelect and explain. \nA. Ethosuximide, B. Vigabatrin, C. Phenobarbitone, D. Levetiracetam', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Vigabatrin is implicated in causation of constriction of visual field.', 'role': 'assistant'}]