Treatment of acquired nystagmus with botulinum neurotoxin A
M. X. Repka, P. J. Savino and R. D. Reinecke
Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, Md.
OBJECTIVE: Acquired nystagmus may cause oscillopsia and in some cases
decreased visual acuity. Such symptoms may be debilitating. We evaluated
the efficacy of retrobulbar botulinum neurotoxin A in the visual
rehabilitation of patients with acquired symptomatic nystagmus. PATIENTS:
Adults with acquired nystagmus from multiple sclerosis or brain-stem
hemorrhage were recruited for this treatment study. Eligible patients were
unable to perform visual tasks that they had performed prior to the onset
of the nystagmus. DESIGN AND INTERVENTION: A prospective study evaluated
the results of the retrobulbar injection of 25 to 30 U of botulinum
neurotoxin A. Patients underwent testing of visual function, including eye
movement recordings before and after initial injections. Patients were
followed up for changes in their visual function for at least 6 months
following the last injection. RESULTS: Six patients (nine eyes) with
acquired nystagmus were treated with a series of 17 injections of
retrobulbar botulinum neurotoxin A. Each patient had subjective and
objective improvement in distance visual acuity following the injection. A
reduction in the amplitude of the nystagmus was seen following each of the
injections, but the frequency of the nystagmus was generally unchanged.
Visual improvement usually lasted no more than 8 weeks. However,
improvement persisted for 6 months after injection in two patients with
oculopalatal myoclonus. CONCLUSION: Botulinum neurotoxin A transiently
improves the visual function of patients with acquired nystagmus. For
patients with oculopalatal myoclonus the improvement seems to last longer,
about 6 months in two patients.
