Safety assessment of using incobotulinumtoxin A in the treatment of concomitant strabismus in children

Background: strabismus is a significant pathology that presents both aesthetic and functional challenges. Chemodenervation with botulinum toxin type A (BoNT-A) is a well-established treatment for strabismus that has been in use since the 1980s. The technique of chemodenervation continues to evolve, with various new administration methods and formulations, all of which are based on BoNT-A. Of particular interest is a modification purified of immunogenic complexing proteins, which reduces the risk of sensitization and diminishes the likelihood of decreased efficacy with repeated injections. In the scientific literature, this formulation is commonly referred to as incobotulinumtoxin A. However, there is a paucity of data regarding the use of incobotulinumtoxin A in ophthalmology, and associated risks remain unclear. This study describes the results of an atraumatic chemodenervation technique using a new-generation BoNT-A preparation. Aim: to assess the efficacy and safety of an atraumatic method for the treatment of concomitant strabismus in children using incobotulinumtoxin A. Patients and Methods: the study included 40 patients (80 eyes) aged 1 to 12 years with concomitant strabismus who underwent chemodenervation with incobotulinumtoxin A. Prior to chemodenervation, patients underwent an evaluation of their general somatic status and ophthalmological examination. An atraumatic forceps was used to access the extraocular muscles. The study was approved by the local Ethics Committee of the N.I. Pirogov Russian National Research Medical University. Results: no adverse events in general health status or systemic function were observed. No complications requiring additional medical intervention occurred. The overall efficacy rate was 87.5%. Only transient adverse events were identified, including ptosis (36.84%), hypercorrection (28.07%), and subconjunctival hemorrhage (hyposphagma, 7.02%). These transient events did not impair patients' quality of life, did not require treatment, and resolved spontaneously within four weeks. Conclusion: atraumatic chemodenervation using incobotulinumtoxin A injections is an effective and safe method for the correction of concomitant strabismus in children. The absence of systemic reactions and complications, short procedure duration (~5 minutes), and transient nature of adverse events confirm its suitability for pediatric ophthalmology. KEYWORDS: incobotulinumtoxin A, botulinum toxin type A, extraocular muscle pathology, concomitant strabismus, chemodenervation, transient ptosis, minimally invasive treatment. FOR CITATION: Cha V.S., Sidorenko E.E., Sidorenko E.I., Miguel D.V., Ermolaeva E.V., Loskutova V.E., Stepashkina A.D. Safety assessment of using incobotulinumtoxin A in the treatment of concomitant strabismus in children. Russian Journal of Clinical Ophthalmology. 2025;25(3):185–190 (in Russ.). DOI: 10.32364/2311-7729-2025-25-3-4