Intramuscular Botulinum Neurotoxin Injections for Infantile Esotropia: A Durban Academic Hospital Review

Background: Infantile esotropia is characterised by a constant, large-angle strabismus present before 6 months of age. Botulinum neurotoxin (BNT) injections offer a potential alternative to surgical correction. Aim: To evaluate the effectiveness and safety of bilateral medial rectus BNT injections in managing infantile esotropia in children younger than 2 years. Setting: The study was conducted at a quaternary hospital in KwaZulu-Natal, South Africa. Methods: A retrospective chart review was performed for patients who received bilateral medial rectus BNT injections over a 7-year period. The primary outcome was the change in the angle of deviation from baseline to 6 months post-treatment. Success was categorised as complete, partial or qualified. Secondary outcomes included complications and demographic factors. Results: The study assessed 41 patients. Most patients were African (90.20%) with large-angle esotropia (85.20%). The mean pre-treatment angle of deviation in the study population was 64.00 prism dioptres (PD). This decreased to a mean post-treatment angle at 6 months of 31.40 PD. There were 28 successes (68%) at 6 months, which comprised 18 patients (43.9%) who had complete or partial success and 10 patients (24.4%) with qualified success. Conclusion: Botulinum neurotoxin injections can be considered as a first-line treatment for infantile esotropia in patients under 2 years, regardless of the initial angle of deviation and are effective and safe. Contributions: Botulinum neurotoxin injections offer a viable alternative to surgery in resource-constrained settings where theatre time may be limited.