Start Botulinum Toxin Early Against Acquired Esotropia, Study Says

While currently only estimated to make up 0.3% of pediatric strabismus cases, acute acquired comitant esotropia (AACE) has become increasingly common in clinical practice recently. It is currently believed that onset is probably associated with prolonged near work, fusional vergence dysfunction and physical and psychological stress. Botulinum toxin type A (Botox) injection is one of the mainstay interventions that has unique advantages, including reducing recovery time, improving stereoacuity and minimizing scar formation. A recent study published in BMC Ophthalmology observed the recovery of eye alignment and binocular visual function in patients with AACE with different clinical characteristics after Botox injection and analyzed the possible influencing factors. The duration of strabismus, age of onset and pre-injection fusion function may be important factors affecting the efficacy of Botox injections in patients with AACE. Photo: Dhoot A, et al. McGill J Med. 2022 Apr. 19. Click image to enlarge. “When using botulinum toxin type A for AACE, it is advisable to start early, assess each patient individually and adopt a personalized treatment plan,” the researchers wrote in their paper.A retrospective analysis of 35 patients with AACE who received Botox microinjections was conducted for this study.  The patients’ average age of onset was 8.86 (range: three to 21 years). The mean duration of strabismus was 3.37 months (range: 0.23. All patients were followed up at least six months after injection, with an average follow-up time of 8.49 months.Compared with the deviation angle before Botox injection, the deviation angle of both near and distant fixation after injection was significantly lower. The success rate was 80% in our study. The positive rate of simultaneous vision, fusion range, positive rate of distant stereopsis and near stereopsis were all improved after treatment.The age of onset (OR = 1.477), duration of strabismus (OR = 1.615) and fusion range before injection (OR = 0.722) are related to recurrence rates, the researchers noted in their paper. The duration of strabismus (OR = 0.799) was also related to the near stereoacuity after injection.“Our data showed that for every additional month of strabismus duration, the risk of recurrence at the last follow-up increased by about 68.1%,” the study authors wrote. “Longer strabismus duration will also reduce the probability of near stereopsis recovery.”One patient with recurrence was treated one month after the onset of strabismus, and the remaining patients with recurrence had a duration of strabismus longer than three months. At follow-up, the researchers learned that this patient did not adhere to wearing myopic corrective glasses after treatment, and they speculated that his recurrence might also be related to this. This reason suggests that patients’ compliance with post-treatment guidance (such as insisting on wearing glasses and reducing near work time) may affect the success of Botox treatment.The team suggested that future studies with a longer follow-up period may better demonstrate the durability of this intervention.Click here for the journal source. Zhang H, Han H, Xu H, et al. Botulinum toxin for acute acquired comitant esotropia: clinical outcomes and predictors. BMC Ophthalmol. 2025;25(1):607. This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.