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

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 delta of exotropia (range 12 to 85 delta exotropia) and the minimum mean angle change after 1 injection was 27 delta (range 0 to 57 delta). 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.