Treatment of acquired nystagmus with botulinum A toxin.

We injected botulinum A toxin into the retrobulbar space of one eye each in two patients who had acquired nystagmus with oscillopsia and decreased vision. After injection of 25 units of botulinum A toxin, visual acuity improved from 20/80 to 20/30 in one patient, and both patients were able to read and watch television. Improved vision lasted from five to 13 weeks. No adverse side effects were observed after a total of five injections in each patient.