title: Inferior Oblique Botulinum Toxin Injection: A Postoperative Diplopia Test for Secondary Inferior Oblique Muscle Overaction.
abstract: OBJECTIVE
  To evaluate the utility of botulinum toxin injection into the inferior oblique muscle for secondary inferior oblique muscle overaction.
  
  
  METHODS
  A retrospective review of 18 patients and 23 injections performed over a 9-year period. Indications and deviations in primary position and contralateral gaze before and after injection were recorded. Functional outcomes and further management (conservative vs surgical) were observed.
  
  
  RESULTS
  In 14 patients, chemodenervation resulted in a temporary improvement in symptoms. Eleven of these patients went on to have inferior oblique myectomy with resolution of their diplopia. Two patients preferred to receive regular injections of botulinum toxin as a treatment.
  
  
  CONCLUSIONS
  Botulinum toxin chemodenervation of the inferior oblique muscle in cases of secondary inferior oblique muscle overaction is useful where one needs to establish a risk of overcorrection following planned inferior oblique muscle weakening. This is particularly true in cases where the primary position deviation may be small but symptoms of diplopia exist on contralateral side gaze, giving rise to a narrowed field of binocular single vision.
authors: Shveta
authors: S
authors: Bansal
authors: Ian B
authors: IB
authors: Marsh
mesh_terms: D000328:Adult; D000368:Aged; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D004172:Diplopia / Q000175:diagnosis*; D004576:Electromyography; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D008875:Middle Aged; D009407:Nerve Block; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D009801:Oculomotor Muscles / Q000187:drug effects*; D012189:Retrospective Studies; D020432:Trochlear Nerve Diseases / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology; D055815:Young Adult
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A; C545476:incobotulinumtoxinA