The role of botulinum toxin in management of infantile esotropia

Abstract

Purpose: To find out the effect of a single dose botulinum toxin injection. Methods: This study is an observational case series. Data of patients with infantile esotropia who received a single dose of botulinum toxin in 6th-9th month of their age were retrospectively reviewed during the period from February 2013 to January 2015. Botulinum toxin was injected in each of medial recti with a dose of 5 IU/0,05 mL without Electromyography (EMG) control. Five patients were included in the study. Complications reletad to injection and to the toxin were recorded. During their regular follow-ups, the parents were instructed to patch the dominant eye if there is fixation preference either in exotropia or esotropia phases. Patients were examined between their 72nd to 96th month to find out their current visual acuity and to observe if they had any late term accompanying squints, nystagmus and amblyopia. Snellen optotypes or pictures were used for detecting best-corrected visual acuity. Results: Orthophoria was the main outcome for 3 of the 5 patients. Dissociated deviations and latent nystagmus did not develop on any patient. On the last examination, patients’ visual acuities were assesed. Orthophoric ones: One patient had 1.0/1.0 visual acuity, one patient had 0.4/0.6 visual acuity, one patient had 0.2/0.2 visual acuity. Monocular esotropia ones: On the strabismic eye 0.1, on the dominant eye 1.0 visual acuity was detected. Inferior oblique muscle hyperfunction developed post injection on all the patients. Conclusions: Botulinum toxin injection caused infantile esotropia to change into a more manageble form.