Long-term results of botulinum toxin in consecutive and secondary exotropia: Outcome in patients initially treated with botulinum toxin

Abstract

Introduction: Long-term ocular alignment can be difficult to achieve in patients with consecutive and secondary (sensory) exotropia, and botulinum neurotoxin A (BTXA) is a recognized alternative to surgery in this group. Patients and Methods: We reviewed the results of 44 patients aged 15 to 77 years (mean 31 years) who underwent their first BTXA injections from 1989 to 1990. In 30% of cases the choice of toxin treatment was made by the patient. In the remainder BTXA was recommended by the clinician to assess the risk of postoperative diplopia. Thirty-three patients (75%) were consecutively exotropic and 68% of patients had had previous strabismus surgery. The mean preinjection deviation was 41 Δ of exotropia (range 12 to 85 Δ exotropia) and the minimum mean angle change after 1 injection was 27 Δ (range 0 to 57 Δ). The average number of injections was 3 (range 1 to 17). Results: Of the patient group, 59% went on to strabismus surgery, 14% continued to attend for maintenance treatment, and 9% were discharged with a small, stable deviation. The remainder were either followed up elsewhere or failed to reattend. Conclusions: Botulinum toxin appears to be a satisfactory treatment for constant exotropia in patients at risk of postoperative diplopia who have undergone multiple operations but, because more than half the group went on to surgery, surgery as a first therapy may be preferable in uncomplicated cases.