Botulinum toxin type A injection in treatment of pediatric cyclic esotropia

This study aimed to assess the long-term motor, sensory, and safety outcomes following botulinum toxin type A (Botox®) injection for cyclic esotropia in children.

We retrospectively enrolled children with cyclic esotropia receiving botulinum toxin type A injections between May 2023 and February 2025 who had a minimum 12-month postoperative follow-up. All subjects received complete ophthalmologic assessments comprising best-corrected visual acuity (BCVA), spherical equivalent (SE), and fundus photography, alongside dedicated strabismus evaluations for deviation angle, ocular motility, and binocular function. Ocular deviation and binocular function (distance and near stereopsis) were measured at baseline and scheduled follow-up visits at 1 week, 1, 2, 3, 4, 6 and 12 months postinjection. All adverse events emerging throughout follow-up were prospectively recorded. Treatment success was defined as no recurrence of cyclic esotropia with residual manifest deviation ≤ 5 prism diopters (PD).

Seven pediatric patients (2 males, 5 females; aged 3-5 years) were enrolled in this cohort. At 3 months postinjection, six subjects achieved orthotropia within ± 5 PD, while one developed transient recurrent deviation. Notably, none demonstrated persistent cyclic esotropia. Adverse events were identified in all patients at the 1-week follow-up: upper eyelid ptosis in 6 of 7 patients (85.7%), consecutive exotropia in 6 of 7 (85.7%), and vertical strabismus in 2 of 7 (28.6%). Two new-onset vertical strabismus cases were detected at the 1-month visit, raising the overall prevalence to four patients. Partial recovery was observed in 4/6 (66.7%) ptosis cases, 4/6 (66.7%) consecutive exotropia cases, and none of the four vertical strabismus cases; meanwhile, binocular function improved in 2/7 (28.6%) children. By the 3-month follow-up, complete resolution was seen in all ptosis (6/6, 100%) and consecutive exotropia (6/6, 100%) cases, alongside improvement in 3/4 (75%) vertical strabismus and 6/7 (85.7%) binocular function. At the 12-month endpoint, all seven patients, including the single case with transient early recurrence at 3 months, maintained ocular alignment within ± 5 PD with no recurrent cyclic deviation, and binocular function recovered to near-normal levels across the entire cohort.

Botulinum toxin type A injection effectively interrupts the cyclic deviation pattern and yields durable ocular alignment in this small cohort of children with cyclic esotropia. The majority of injection-related adverse events resolved by 3 months, with complete resolution of all complications by 4 months. Accordingly, botulinum toxin type A injection represents a viable nonsurgical alternative for the management of pediatric cyclic esotropia.