Botulinum toxin for acute acquired comitant esotropia: clinical outcomes and predictors.

[BACKGROUND] To assess the effectiveness of botulinum toxin type A (BTXA) in treating acute acquired comitant esotropia (AACE), and to explore its possible influencing factors.

[METHODS] A retrospective analysis of 35 AACE patients who received BTXA microinjections between July 2023 and November 2024 was conducted for this study. Record the deviation angle, simultaneous vision function, fusion function, distant and near stereopsis before and after BTXA injection. The Wilcoxon signed-rank test and the Exact McNemar test were used to compare the data before and after injection. Univariate logistic regression analysis and Multivariable logistic regression analysis were used to explore the factors related to therapeutic effect.

[RESULTS] The patients’ average age of onset was 8.86 ± 4.16 years (range: 3 to 21 years). The mean duration of strabismus was 3.37 ± 3.27 months (range: 0.23 to 14 months). All patients were followed up at least 6 months after BTXA injection, with an average follow-up time of 8.49 ± 3.82 months (range: 6 to 17 months). Compared with the deviation angle before BTXA injection, the deviation angle of both near ( < 0.001) and distant ( < 0.001) fixation after injection was significantly lower. The success rate was 80% in our study. The positive rate of simultaneous vision ( = 0.002), fusion range ( < 0.001), positive rate of distant stereopsis ( = 0.013) and near stereopsis ( < 0.001) were all improved after BTXA treatment. The age of onset(OR = 1.477, 95%CI 1.052–2.073,  = 0.024), duration of strabismus (OR = 1.615, 95%CI 1.088–2.396,  = 0.017) and fusion range before injection (OR = 0.722, 95%CI 0.541–0.963,  = 0.027) are related to recurrence. The duration of strabismus (OR = 0.799,95%CI 0.643–0.993,  = 0.043) was also related to the near stereoacuity after injection.

[CONCLUSION] BTXA injection can effectively decrease the deviation angle while also restoring the binocular visual function (BVF) of AACE patients. The duration of strabismus, age of onset, and BVF before injection may be important factors affecting the efficacy of BTXA.