Abstract
Purpose: :
Vigabatrin (vgb) is an antiepileptic drug that is used to treat children with the childhood epilepsy Infantile Spasms (IS). Vgb has been found to be a especially efficacious anticonvulsant in patients with Tuberous Sclerosis (TS) as well as IS. Treatment with vgb results in significant reduction of 30 Hz flicker amplitude, compared with the pre-drug ERG, in 25% of infants after 15 months on the drug. Before vigabatrin treatment about 25% of infants have abnormal 30 Hz flicker amplitude complicating assessment of retinal function during treatment. This project investigated if retinal function in infants with TS was different from children with Infantile Spasms and no TS (non-TS group) before and during vgb treatment.
Methods: :
Case control study including 22 infants with IS diagnosed with TS, matched with infants with IS diagnosed with other aetiologies; based on age at which vigabatrin treatment was started. ISCEV standard ERG responses were assessed before vgb treatment and at approximately 3 month intervals after starting vgb. ERG amplitudes were compared between groups.
Results: :
Before vgb treatment the non-TS group showed reductions in amplitude in cone a, cone b, rod b and flicker responses before VGB treatment (ANOVA p= 0.0015) but not in the rod-cone a and b amplitudes. There was no significant difference in the reduction in flicker amplitude between patients with TS and patients with other underlying aetiologies after 9 months or after 15 months of vigabatrin treatment.
Conclusions: :
Children with aetiology of Tuberous Sclerosis have retinal function within normal limits before initiation of vigabatrin resulting in an enhanced ability to monitor retinal toxicity using ERGs in this group.
Keywords: electroretinography: clinical • drug toxicity/drug effects • neuro-ophthalmology: diagnosis