Injection of type A botulinum toxin into extraocular muscles for correction of strabismus.
Between July 1984 and March 1985, 51 injections of type A botulinum toxin were given to 39 patients aged 11 to 81 years with various types of strabismus, including paralytic strabismus, sensory exotropia, consecutive and residual postsurgical deviations and partially accommodative esotropia. All deviations were documented by orthoptic assessment and photography. After treatment the patients were followed for up to 3 years. The beneficial effects of a single injection were modest, and a second injection was often necessary to achieve satisfactory ocular alignment. Thirteen of the 26 patients (50%) with nonparalytic strabismus and 10 of the 13 patients (77%) with paralytic strabismus had a good outcome (final deviation 12 prism dioptres or less). Adverse side effects included transient ptosis and diplopia and inadvertent vertical deviation. Twenty-one consecutive cases of nonparalytic horizontal strabismus treated with adjustable sutures were also reviewed. The results in these patients were more predictable and longer lasting than those in the patients who received botulinum toxin.