Tonic pupil after botulinum toxin-A injection for treatment of esotropia in children

Abstract

A total of 27 children with esotropia (mean age, 3.9 years; range, 9 months to 13.8 years) were enrolled in a 9-month observational study following botulinum toxin A (BTX-A) injection of one (n = 7) or both (n = 20) medial rectus muscles. BTX-A dosage ranged from 3.0 to 6.0 units per muscle. Three participants developed tonic pupil, noted at the first follow-up visit, occurring 12-19 days after injection. All 3 cases occurred in the left eye of participants who underwent bilateral BTX-A injection by the same surgeon. Anisocoria diminished from a maximum of 4 mm at the 2-week visit to 1-2 mm in all patients over the 9-month postinjection data collection period. No adverse visual outcomes were noted. Tonic pupil is an infrequently reported complication of BTX-A injection for strabismus. The experience of our investigator group suggests the need for careful injection technique and thorough preinjection counseling.

Copyright © 2016 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

Figures

FIG 1

Pre- and postinjection photographs showing pupil findings in a patient who developed a tonic left pupil after botulinum toxin-A injection of both medial rectus muscles for treatment of strabismus. A, Preinjection. B, 2 weeks after injection. C, 55 days after injection. D, 55 days after injection, post-pilocarpine. In this patient, as in all cases, affected pupils showed minimal responsiveness to light but constriction with fixation on a near accommodative target. Anisocoria was reversed after treatment of both eyes with pilocarpine 0.125%, diagnostic for tonic pupil.