Role of inferior rectus botulinum toxin injection in iatrogenic vertical strabismus

Abstract

Introduction: We describe the uses and effectiveness of botulinum toxin to the inferior rectus muscle in iatrogenic vertical strabismus.

Methods: A retrospective review of our database to identify patients who had undergone inferior rectus botulinum toxin injection between 1982 and 2006 for iatrogenic vertical strabismus.

Results: There were 13 patients, 5 female, with an age range of 14 to 78 years. Eight left eyes were injected. The mean period of follow-up was 3.3 years. Etiologies included post-local anesthetic, post-plaque radiotherapy for malignant melanoma, adherence syndrome after inferior oblique surgery, and post-botulinum toxin to the levator muscle to produce a temporary therapeutic ptosis. Reversal on first injection occurred in 7 patients and occurred in a further 2 patients on second injection. Pre-injection binocularity was not demonstrable in 3 patients; 2 of these patients did have binocular vision demonstrable after botulinum toxin injection. Seven patients had one injection, 3 patients had two, 1 had three, 1 had five, and 1 had six.

Discussion: The data demonstrate the range of indications that can be successfully treated and managed with inferior rectus botulinum toxin injection in iatrogenic vertical strabismus.