In a child of infantile spasm and visual defect, which drug is not used even though it is highly effective?

Two types of drugs are used in infantile spasm:* ACTH (drug of choice)* Vigabatrin (drug of choice if infantile spasm with Tuberous sclerosis)Vigabatrin is a GABA transaminase inhibitor. Major side-effect is visual field defect. It is indicated in Refractory focal seizures with impaired awareness.So, because of this side-effect it can't be used if the child already has visual defect.