title: The clinical spectrum of amiodarone-associated optic neuropathy.
abstract: OBJECTIVE
  To describe the clinical spectrum of amiodarone-associated optic neuropathy.
  
  
  METHODS
  Observational cases series and review.
  
  
  RESULTS
  Of 55 cases, the median interval for onset of optic neuropathy was four months after initiating amiodarone; 88% occurred within 12 months. Seven (13%) patients were asymptomatic. Twenty-two (40%) patients presented with sudden visual loss, while 26 (47%) had insidious loss of vision. Visual acuity ranged from 20/15 to light perception; 10 (18%) patients had legal blindness with visual acuity of 20/200 or worse. Visual field loss was present in 91% of cases. Color vision loss was present in eight (40%) of 20 cases. Optic disc edema was present in 85% of cases, while eight (15%) patients had retrobulbar optic neuropathy, without evidence of disc edema. Optic disc edema resolved over a median time of three months. Five patients had raised intracranial pressure on lumbar puncture.
  
  
  CONCLUSIONS
  We were able to classify amiodarone-associated optic neuropathy into five clinical categories with respect to temporal characteristics and optic nerve appearance: insidious-onset (43%), acute-onset (28%), retrobulbar (13%), increased intracranial pressure (8%), and delayed-progressive onset (8%). Most cases of optic neuropathy commenced within 12 months of initiating amiodarone, with the median onset being four months. Over 10% of patients will have no visual symptoms at the onset. Ophthalmologic examinations within the first 12 months--and particularly within four months of initiating amiodarone--should improve early detection of amiodarone-associated optic neuropathy.
authors.affiliation: Neuro-Opthalmology Unit, Mason Eye Institute, University of Missouri-Columbia, Columbia, MO 65212, USA. JohnsonLN@health.missouri.edu
authors.forename: Lenworth N
authors.initials: LN
authors.lastname: Johnson
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Krohel
authors.forename: Eric R
authors.initials: ER
authors.lastname: Thomas
mesh_terms: D000368:Aged; D000638:Amiodarone / Q000009:adverse effects*; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000187:drug effects; D009901:Optic Nerve Diseases / Q000139:chemically induced* / Q000145:classification / Q000473:pathology; D013997:Time Factors
chemical_list: D000889:Anti-Arrhythmia Agents; D000638:Amiodarone