To compare the efficacy of botulinum toxin injections to strabismus surgery in children with acute, acquired, comitant esotropia (ACE), and to investigate factors predicting success.

International, multi-center nonrandomized comparative study

Setting: Cloud-based survey. Study population: Children aged 2 to 17 years who underwent a single surgical intervention for ACE. Interventions: Botulinum toxin injection (“chemodenervation” group) or strabismus surgery (“surgery” group). Main outcome measures: Primary measure: success rate at 6 months in propensity-matched cohort, defined as total horizontal deviation of 10 prism diopters or less with evidence of binocular single vision. Secondary measure: Risk factors for poor outcomes in the full cohort.

Surgeons from 19 centers contributed. There were 74 patients in the chemodenervation group and 97 patients in the surgery group. In the propensity-matched data (n = 98), success rate was not significantly different at 6 months (70.2% vs 79.6%; P = .2) and 12 months (62.9% vs 77.8%; P = .2), but was significantly lower in the chemodenervation group at 24 months (52% vs 86.4%; P = .015). Irrespective of treatment modality, treatment delay was associated with lower success rates at 6 months, with median time from onset to intervention 4.5 months (interquartile range (IQR): 2.1, 6.7) in the success group and 7.7 months (IQR: 5.6, 10.1) in the failure group (P < .001).

In children with ACE, success rate after chemodenervation was similar to that of surgery for up to 12 months but lower at 24 months. Those with prompt intervention and no amblyopia had the most favorable outcomes, regardless of treatment modality.