Abstracts

Rationale: This case report is important because this child had reversible visual symptoms, visual fields and ERG changes while on Vigabatrin. The current FDA Black Box warning states that irreversible peripheral visual loss and ERG changes may occur with this drug. Methods: Pediatric neurology patients with infantile spasms on the drug Vigabatrin were examined by a neuro-ophthalmologist. Data on each child varied over the years as the children grew older and were able to cooperate. Visual acuities, pupil exams, motility exams, retinal exams, visual fields by Goldmann kinetic and Humphrey static techniques, ERG testing, OCT (optical coherence tomography)imaging and MRI imaging were all collected on this child. Results: This child had infantile spasms starting at the age of 1 month in 2003. Two drugs failed to help, but at 6 months, Vigabatrin stopped his seizures by day 5. Baseline vision exams, ERG testing and CT of the brain were normal. At 18 months of age, still on Vigabatrin, he became both photophobic and afraid of the dark. Visual acuities were 20/60 OD and 20/40 OS estimated by fixation targets. Visual fields became constricted with a right homonymous inferior quadrantanopsia. ERG testing became abnormal at 18 months. The family chose to continue using the drug because of his clinical control on it. At age 41 months, his vision improved, visual fields expanded to normal (except for the right quadrantic defect) and ERG returned to normal while still on Vigabatrin. His seizures increased in frequency at 43 months and a left parietal cortical resection was done. Pathology showed cortical dysplasia. Genetic testing revealed the TSC2 genotype. Postoperatively, he was tapered off Vigabatrin over 10 months, and transitioned to Trileptal. At 7 years, he remains seizure-free on Trileptal and Rapamycin. His first Humphrey visual field tests showed the fixed right quadrantic defect (see image 1), and his first OCT testing of the macula showed a normal retinal thickness (image 2) after 4 years of Vigabatrin therapy. Conclusions: Not all visual symptoms, visual field losses and ERG changes are irreversible with the drug Vigabatrin.