Anterior Ischemic Optic Neuropathy (AION) – Etiology, Clinical features, Investigations, Treatment

  • Anterior Ischemic Optic Neuropathy is a condition in which there is segmental or total infarction of the anterior part of the optic nerve

Etiology:

  • AION occurs due to blockage of Short posterior ciliary arteries which supply the optic nerve
  • The different types of AION are:
    • Idiopathic – most common – thought to be due to atherosclerotic changes in the vessels
    • Arteritic – associated with giant cell arteritis
    • Miscellaneous – associated with various conditions like
      • Severe anemia
      • Malignant hypertension
      • Papilledema
      • Migraine
      • Massive haemorrhage
      • Collagen vascular disorders

Clinical features:

  • Sudden visual loss
    • involving the upper or lower (more common) half of the visual field – altitudinal hemianopia
  • Fundus changes – disc
    • oedematous (segmental / diffuse)
    • pale or hyperemic

Investigations:

  • ESR and C reactive protein may be elevated in the arteritic variety
  • Definitive diagnosis of arteritic AION is by temporal artery biopsy

Treatment:

  • High dose steroids (prednisolone 80mg daily) – taper it by 10mg every week
  • Low dose steroids may have to be given for 3 months to 1 year

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AION – Acronym

AION stands for: Anterior Ischemic Optic Neuropathy

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