Does botulinum toxin have a role in the treatment of secondary strabismus?*

We reviewed the Toxin Clinic database over a 20-year period, identifying patients with strabismus secondary to permanent or temporary impairment of vision.

Five hundred-and-three patients who fulfilled our criteria were treated with Botulinum toxin. There were 301 males and 202 females, with a mean age at treatment of 35 years (range 6-86). Three hundred-and-eighty-three patients (76%) had exotropia, 114 (22.5%) had esotropia and 6 (1.5%) had vertical strabismus. Reduced vision secondary to trauma accounted for 45% (227) of patients. Other causes were congenital anomalies 121 (24%), refractive error 30 (6%), retinal detachment 20 (4%), senile cataract 24 (5%), corneal problems 19 (4%), glaucoma 10 (2%) and other 52 (10%). One hundred-and-ninety-three (38%) were aphakic. One thousand-four-hundred-and-fifty-seven injections were given, with a range of 1-50 per patient. Ninety-nine (20%) patients were managed with continued toxin treatment. Two hundred-and-eighteen patients (43%) proceeded to surgery. Forty patients (8%) required no further treatment as they regained binocularity by injection alone.

Botulinum toxin appears to have a role in the treatment of secondary strabismus, since only 3% (14) failed to obtain any reduction in their angle. It was well tolerated, with no permanent side effects. Only 22 (4%) patients developed ptosis.