Abstract
Introduction: Oscillopsia is the characteristic symptom of patients who develop acquired nystagmus. Most treatment options for this incapacitating condition are unsatisfactory. We evaluated the efficacy of retrobulbar Botulinum Toxin in treating patients with diminished visual acuity due to oscillopsia. Methods: A retrospective review was conducted using the Toxin Clinic database between 1990 and 2003. All patients were treated with 25 units of Botulinum Toxin A, given by retrobulbar injection. Seventeen patients were identified, 9 females and 8 males. The average age at treatment was 45 years. Results: Eight patients had multiple sclerosis, 4 had brainstem hemorrhage, 2 had brainstem cavernous hemangioma. One patient had oscillopsia and bilateral INO following neurosurgery for a frontoparietal meningioma. Two patients had sensory nystagmus, one secondary to oculo-cutaneous albinism and the other congenital cataracts. The patients with multiple sclerosis and brain stem hemorrhage had pendular rotary nystagmus. The patients with brainstem cavernous hemangioma had horizontal and vertical nystagmus. The patient with oculocutaneous and congenital cataracts had pendular rotary nystagmus. Twelve patients were wheelchair bound. Pre-treatment vision in the treated eye ranged from 1/60 to 6/9. Patients occluded the other eye post treatment if they had constant diplopia. Eleven patients were aware of improvement after injection. This was confirmed on formal testing in 12 patients. One patient improved by 4 Snellen lines, 2 gained 3 lines, 3 gained 2 lines, and 6 gained one line. The maximum improvement was from 6/60 to 6/12. Six patients found no subjective improvement, although in 3 there was one line improvement. In 3 cases there was no change measured in visual acuity. Four patients had continuing toxin injections for relief of symptoms. Conclusion: Retrobulbar injections of Botulinum Toxin provide both subjective and objective improvement in the symptoms. Patients who are wheelchair bound benefit more from this treatment.
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