Efficacy of Botulinum Toxin Type A for Acute Acquired Comitant Esotropia: An Age-Stratified 2-Year Follow-Up Study.

PURPOSE: To assess and compare the 2-year follow-up efficacy of botulinum toxin type A (BTXA) in the treatment of acute acquired comitant esotropia (AACE) across five age groups.

DESIGN

Retrospective clinical cohort study.

METHODS

A total of 276 patients with AACE who received BTXA injections were enrolled from a single institution between January 2019 and January 2023 (Notably, surgery was recommended for patients >12 years with large-angle esotropia (>50 prism diopters) to reduce failure or recurrence risk). Patients were stratified into five age groups based on intervention age: ≤6 years, >6 to ≤12 years, >12 to ≤20 years, >20 to ≤30 years, and >30 years. The primary outcomes included the cumulative motor and sensory success rates across different age groups, as well as the hazard ratio (HR) for the risk of AACE relapse.

RESULTS

The median age of the 276 participants was 18 years (interquartile range: 9-30 years), with 125 (45.29%) being female. The overall 2-year motor success rate of BTXA for AACE treatment was 69.03% (95% confidence interval [CI]: 62.30%-74.81%). Notably, the motor success rate exhibited a tendency to decline with age, and patients older than 30 years showed significantly lower motor success rate compared to other age groups (≤6 years: 86.53%, >6-≤12 years: 79.96%, >12-≤20 years: 74.08%, >20-≤30 years: 67.45%, >30 years: 44.29%, Bonferroni-corrected posthoc test: P < .05/4). Similarly, patients aged >30 years demonstrated significantly lower rates of stereopsis recovery post-treatment compared to younger cohorts (Bonferroni-corrected posthoc test: P < .05/4). Furthermore, hours of near-work per day (HR: 1.09, 95% CI: 1.01-1.17) and age (HR: 1.04, 95% CI: 1.02-1.06) were identified as significant risk factors for AACE relapse following BTXA injection.

CONCLUSIONS

In this retrospective cohort study, our findings demonstrated that younger AACE patients (≤30 years) exhibited significantly greater treatment stability and success rates following BTXA injection therapy. Postoperative preservation or achievement of normal stereopsis can serve as a reliable predictor of reduced recurrence risk.