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
A patient on anti-epileptic drugs now complains of progressive B/L constriction of visual fields. Pt is on which drug? 
Select and explain. 
A. Ethosuximide, B. Vigabatrin, C. Phenobarbitone, D. Levetiracetam
B: Vigabatrin
Answer: B: Vigabatrin 
Explanation: Vigabatrin is implicated in causation of constriction of visual field.