Efficacy of augmented-dosed surgery versus botulinum toxin A injection for acute acquired concomitant esotropia: a 2-year follow-up

Background/aims This study aims to evaluate the clinical efficacy of botulinum toxin type A (BTXA) injection and augmented-dosed surgery in the treatment of acute acquired concomitant esotropia (AACE), and explore potential risk factors associated with recurrence. Methods A total of 104 patients diagnosed with AACE between October 2020 and January 2021 were included and voluntarily chose to undergo augmented surgery or BTXA injection. The follow-up assessments ended in November 2022. Multivariable linear regression analysis was used to identify potential factors that influence the dose-response of bilateral medial rectus recession (MRrec). Kaplan-Meier survival analyses and Cox proportional hazards models were performed to evaluate rate and risk factors for AACE relapse. Results A total of 31 AACE patients chose augmented-dosed esotropia surgery, and 73 chose BTXA treatment. During the 2-year follow-up, the surgical group achieved more stable postoperative results with no recurrence of diplopia, while only 68.68% (95% CI 55.31% to 78.79%) patients achieved orthophoria in the BTXA group. For patients undergoing BTXA treatment, hours of near work per day were demonstrated to be a significant risk factor for AACE relapse (HR 1.29, 95% CI 1.00 to 1.67). The dose-response of augmented-dosed bilateral MRrec was positively correlated with preoperative deviation angle (R 2 =0.833; β=0.043, 95% CI 0.031 to 0.055; p<0.001). Conclusion Our findings provided quantitative evidence that augmented-dosed surgery would achieve more stable and favourable surgical outcomes for AACE patients compared with BTXA injection. However, BTXA treatment is still proposed for patients with small deviation angles due to its advantages of reduced trauma, operational simplicity, low cost and quick recovery.