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: Pharmacology
Which of these anticonvulsants causes contraction of visual field? 
Select and explain. 
A. Levetiracetam, B. Phenytoin, C. Vigabatrin, D. Ethosuximide
C: Vigabatrin
Answer: C: Vigabatrin 
Explanation: Ans: C. VigabatrinVigabatrin:Causes irreversible diffuse atrophy of the retinal nerve fiber layer.Most effect on the outer area (as opposed to the macular, or central area) of the retina, leading to the contraction of the visual field.Retinal toxicity attributed to taurine depletion.