title: Unsatisfactory treatment of acquired nystagmus with retrobulbar injection of botulinum toxin.
abstract: OBJECTIVE
  We quantified the effects of botulinum toxin injected into the retrobulbar space of patients with acquired nystagmus with prominent vertical or torsional components.
  
  
  METHODS
  We measured binocular eye rotations in three planes before and after injection of botulinum toxin (10, 12.5, or 25 units) into the retrobulbar space of one eye of each of three patients, ages 28 to 37 years, with acquired pendular nystagmus.
  
  
  RESULTS
  Retrobulbar injection of botulinum toxin abolished or reduced all components of the nystagmus in the treated eye in all three patients for about two to three months. The patient who received 25 units developed complete external ophthalmoplegia and blepharoptosis. The other two patients retained some voluntary movements but developed diplopia. In one patient, visual acuity improved from Jaeger 5 to Jaeger 1. In a second patient, filamentary keratitis developed, and visual acuity declined from Jaeger 2 to Jaeger 7; keratitis was a recurrent problem one year after the botulinum toxin injection. In the third patient with predominantly torsional nystagmus, visual acuity was unchanged at Jaeger 2. No patient was pleased with the results, because of blepharoptosis, diplopia, or discomfort (from keratitis), and none elected to repeat the procedure.
  
  
  CONCLUSIONS
  The side effects of botulinum toxin administered by retrobulbar injection limit its therapeutic value in the treatment of acquired nystagmus. Even smaller doses that do not abolish nystagmus may produce troublesome diplopia.
authors.affiliation: Division of Ophthalmology, Mount Sinai Medical Center, Cleveland, Ohio, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Tomsak
authors.forename: B F
authors.initials: BF
authors.lastname: Remler
authors.forename: L
authors.initials: L
authors.lastname: Averbuch-Heller
authors.forename: M
authors.initials: M
authors.lastname: Chandran
authors.forename: R J
authors.initials: RJ
authors.lastname: Leigh
mesh_terms: D000328:Adult; D001763:Blepharoptosis / Q000209:etiology; D001905:Botulinum Toxins / Q000009:adverse effects* / Q000627:therapeutic use; D004172:Diplopia / Q000209:etiology; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006801:Humans; D007267:Injections; D007634:Keratitis / Q000209:etiology; D008297:Male; D009759:Nystagmus, Pathologic / Q000503:physiopathology / Q000628:therapy*; D009886:Ophthalmoplegia / Q000209:etiology; D015348:Vision, Binocular; D014792:Visual Acuity
chemical_list: D001905:Botulinum Toxins