Botulinum Toxin A Injection for Convergence Insufficiency.

ABSTRACT

PURPOSE: To evaluate the effects of botulinum toxin A injection in one or both lateral rectus muscles in patients with convergence insufficiency previously managed with non-surgical and/or surgical options other than botulinum toxin A injection. METHODS: All patients with symptomatic convergence insufficiency treated with botulinum toxin A injection to one or both lateral rectus muscles from 2013 to 2018 at the Department of Ophthalmology, Rigshospitalet-Glostrup, Copenhagen University Hospital were retrospectively reviewed. All patients had near symptoms and were previously treated with a combination of convergence exercises, prisms, and/or surgery. Patients with previous botulinum toxin A injection in an extraocular muscle were excluded. Reading symptoms and deviation at near and distance were recorded at baseline and after 1 and 6 months. RESULTS: Twenty-three patients with convergence insufficiency were included (8 men and 15 women). Follow-up was conducted after a median of 47 days (interquartile range [IQR] 31.5 to 72.5 days) and 174 days (IQR 139 to 267 days). At baseline, median near angle of deviation was 18 PD of exophoria (IQR 13 to 21 PD). The near deviation was reduced to 10 PD of exophoria (IQR 7 to 17 PD) at first follow-up visit and 14 PD of exophoria (IQR 12 to 18 PD) at last follow-up visit. Thirteen of 23 patients (57%) and 3 of 13 patients (23%) reported improvement in reading symptoms at first and last follow-up visit, respectively, compared to baseline. CONCLUSIONS: Botulinum toxin A injection may be useful in patients with convergence insufficiency. However, some patients may require repeated injections. [J Pediatr Ophthalmol Strabismus. 2023;60(2)108-113.].