Horizontal recti injection of botulinum toxin for treatment of infantile nystagmus
Reviewed by Fiona Rowe

In this study the authors aimed to demonstrate the effect of botulinum toxin (BT) on the frequency of ocular oscillation in children with infantile nystagmus syndrome (INS). Botulinum toxin was administered with direct injection into the horizontal recti muscles using the Mendonca forceps under general anaesthesia with spontaneous ventilation and without intubation. Hence, this is a less invasive simpler procedure. The study included 50 children – 14 were lost to follow-up leaving 36 patients (75% male) aged 1–14 years (mean 8.22 ±3.61). Five had post injection ptosis resolving over 1–3 months. Mean frequency of oscillations reduced from 1.55 ±0.94Hz pre BT to 1.04 ±0.87 at one-month and 1.27 ±0.87 at six-months follow-up. All reductions were significant. Nine patients (25%) had a frequency of <0.5Hz at their last appointment. In eight children (22.2%) frequency at six-months was similar to baseline and these were offered repeat BT. Eighteen (50%) had a good response but opted for a second injection after six-months to try to further lessen the frequency. The results indicate a significant reduction in oscillation frequency at both one and six-months follow-up, although some increased from one to six months. They suggest the reduction is due to histological changes in the injected muscles. They acknowledge their small numbers, loss to follow-up and inconsistent visual acuity measures. They propose BT as a safe alternative to surgery in the treatment of INS and recommend its use as a procedure.

Botulinum toxin A injection in horizontal nystagmus; effect on the frequency of the oscillation on a pediatric population.
Bergamim D, dos Santos Surgik TC, Zinher MT, de Lassus TCN.
JOURNAL OF PEDIATRIC OPHTHALMOLOGY AND STRABISMUS
2024;61(5):365–70.