Botulinum Toxin A Injection in Horizontal Nystagmus: Effect on the Frequency of the Oscillation on a Pediatric Population.

PURPOSE: To evaluate the effect of botulinum toxin A injection on the frequency of horizontal nystagmus in children.

METHODS: This was a non-randomized before-and-after clinical trial evaluating a cohort of children with horizontal nystagmus before and after treatment with botulinum toxin A. The toxin was injected under general anesthesia with spontaneous ventilation without intubation using the Mendonça forceps and the effect was evaluated by analyzing the frequency of the oscillation in Hertz (Hz) on video registrations before and after treatment.

RESULTS: The current study found a statistically significant difference on the frequency of the nystagmus in children before and after the injection of botulinum toxin A, with the mean frequency decreasing from 1.55 ± 0.94 Hz before treatment to 1.04 ± 0.87 Hz at 1 month post-injection ( P < .001) and to 1.27 ± 0.87 Hz at 6 months post-injection ( P = .002). When comparing the data 1 and 6 months post-injection, this study found a significant increase ( P = .001) in the frequency of the nystagmus.

CONCLUSIONS: The injection of botulinum toxin A is effective in reducing the frequency of oscillations in children with horizontal nystagmus both 1 and 6 months after the procedure, and can be used as a first-line, less invasive treatment aiming to decrease the frequency of oscillation. [ J Pediatr Ophthalmol Strabismus . 20XX;X(X):XXX-XXX.] .