Abstract: Objective To investigate the clinical efficacy of microinjection of botulinum toxin type A(BTX-A)into extraocular muscles through a microsurgical microincision of the bulbar conjunctiva in the treatment of acute acquired concomitant esotropia(AACE). Methods A retrospective analysis of continuous cases was performed. The data of AACE patients treated with BTX-A microinjection in Qingdao Eye Hospital between March 2017 and July 2018 were reviewed. Routine examination was conducted, and the eye position, eye movement, and diplopia before injection were recorded. BTX-A injection was administered under a surgical microscope through a small conjunctival incision of 1-2 mm at the adhesion of the internal rectus muscle to expose its distal end. Routine ophthalmic examination was performed, and eye position, eye movement, and diplopia were examined 1 week, 1 month, and 3 months after the injection. Results A total of 28 AACE patients(30 eyes)were treated with BTX-A microinjection in Qingdao Eye Hospital between March 2017 and July 2018. The average strabismus before treatment was 33.2±15.6^△(+15^△~+60^△). The mean strabismus at 1 week, 1 month, and 3 months of treatment decreased to 9.8±7.2^△ (P< 0.001), 7.8±3.4^△(P<0.001), 9.3±5.2^△(P<0.001), respectively. There were no statistically significant differences in strabismus between the patients who were re-examined 1 week, 1 month, and 3 months after the surgery (P>0.05). Postoperative review after 1 week, 6.7%(2/30)of the injection eye eyelid ptosis slightly, 6.7%(2/30)of the injected eye < 10 training vertical strabismus, 3m re-examination of the above symptoms have disappeared. Three months after the injection, the symptoms of diplopia disappeared in 78.6%(22/28)patients, decreased in 7.2%(2/28)patients, and showed no significant change in 14.2%(4/28)patients. Conclusion BTX-A microinjection for AACE is safe, has a low incidence of complications, is effective, and is an ideal choice for the injection of extraocular muscles without EMG guidance.

Key words: Type A botulinum toxin, Acute acquired concomitant esotropia, Microsurgery