Therapeutic Use of Botulinum Toxin to Correct Misalignment of the Eyes

Abstract

There are no concrete guidelines for the therapeutic use of botulinum toxin in strabismus. The 2012 Cochrane Analysis concluded that it was controversial, but included only 4 prospective randomized controlled trials. However, many retrospective studies suggest that botulinum toxin treatment is a viable alternative to surgical treatment. We have now retrospectively evaluated the outcomes of our patients treated with botulinum toxin. We retrospectively reviewed the charts of the patients treated with Botox® for strabismus. The period covered was between 2003 and 2015, with a follow-up of at least 6 months. Successful outcome was defined as alignment within ≤ 10 prism dioptres, with stereopsis at the final follow-up. 16 patients were included, including 11 children. The mean follow-up was 19 months. All 11 children were initially esotropic; 9 exhibited lasting angle reduction (mean 25.5 prism dioptres) at the final follow-up, and 6 of these (54.5 %) achieved a successful outcome. Only one adult patient achieved a lasting angle reduction. Other benefits were: Psychological relief due to reduced nystagmus (n = 1), relief of headaches from decompensating exophoria (n = 1), and renewed ability to read, due to less adduction of the dominant eye in a patient with bilateral sixth nerve palsy. Transient ptosis without obstruction of the visual axis was seen in 4 (36 %) of the children, but in none of the adults. Botulinum toxin has a lasting effect, especially in children with esotropia. It is minimally invasive and can prevent surgery. If there is subsequent surgery, the dosage may be reduced. Ptosis rates were comparable to those in the literature.