Botulinum Toxin Treatment in Thyroid Eye Disease: A Systematic Review and Meta-analysis

Purpose: Thyroid eye disease–related retraction and strabismus treatment is complicated by the activity level of the disease. Botulinum toxin injection can provide relief of symptoms in lieu of, or while waiting for surgery, radiation, or alternative medications. This study reviews techniques, outcomes, and effectiveness of botulinum toxin usage in thyroid eye disease. Methods: A systematic review was conducted using PubMed, Embase, Web of Science, and Cochrane to identify research investigating botulinum toxin treatment of thyroid eye disease through May 2024. A meta-analysis was performed on change in marginal reflex distance in retraction patients, resolution of diplopia in strabismus patients, necessity of further strabismus surgery, and side effects. Results: Of 157 studies screened by 2 reviewers, 30 underwent analysis. In 19 upper eyelid retraction studies (299 patients), 1.5 to 15 U Botox (onabotulinum toxin A) or 10 to 40 U Dysport (abobotulinum toxin A) was administered to the superior tarsal border, with an 84% success rate and an average decrease in marginal reflex distance of 2.42 mm lasting 1 to 6 months. In 10 strabismus studies (205 patients), 5 to 20 U Botox or 25 U Dysport was administered in extraocular muscles; 24% achieved resolution of diplopia lasting 2 to 6 months, while 58% required further surgical management. In upper eyelid retraction studies, side effects included ptosis (13%) and diplopia (2%). In strabismus studies, side effects included ptosis (2%). Conclusions: This systematic review and meta-analysis confirmed that botulinum toxin is an effective treatment for thyroid eye disease–related lid retraction and strabismus. Randomized controlled studies are warranted to optimize botulinum toxin administration.