Efficacy of Botulinum Toxin Injection in Exotropia Treatment

PURPOSE: Botulinum toxin (Botox) therapy is a well-known option for strabismus management and is often used in managing esotropia. Exotropia is also a common type of strabismus; however, the effectiveness of Botox in improving exotropia is still ambiguous. In this study, we report our experience in using Botox to manage the various types of exotropia. METHODS: A retrospective cohort study was conducted at King Khaled Eye Specialist Hospital Riyadh, Saudi Arabia. Medical records of patients with exotropia who received Botox from 2014 to March 2020 were reviewed. The main success indicator was a remaining angle of less than 10 prism diopters (PD). RESULTS: A total of 97 cases were reviewed, with 57 (58.8%) males and 40 (41.2%) females. The age ranged from 2 months to 40 years. The most prevalent diagnosis was sensory exotropia. Overall, 28 patients (28.9 %) and 49 patients (50.5%) achieved an angle of deviation within 10 PD and within 20 PD, respectively. Female patients had a better response to Botox than males, with 32.5% of them achieving an angle of deviation within 10 PD and 60% achieving an angle of deviation within 20 PD. We found that the change in the angle of deviation increased as the Botox dose was increased. CONCLUSION: Botox represents a possible safe alternative to surgery in the management of some exotropia types. The success rate differs by type, with basic exotropia scoring the highest. The presence of poor vision and amblyopia leads to a significantly lower success rate.