Optic Neuropathy, Ischemic

Key Features

• Sudden painless visual loss with signs of optic nerve dysfunction

• Optic disk swelling in anterior ischemic optic neuropathy

Clinical Findings

• Anterior ischemic optic neuropathy

  • Due to inadequate perfusion of the posterior ciliary arteries that supply the anterior portion of the optic nerve

  • Produces sudden visual loss, usually with an altitudinal field defect, and optic disk swelling

  • In older patients, it is often caused by giant cell arteritis

  • The predominant predisposing factor is a congenitally crowded optic disk

  • Other predisposing factors are systemic hypertension, diabetes mellitus, hyperlipidemia, systemic vasculitis, inherited or acquired hypercoagulable state (thrombophilia), obstructive sleep apnea, and therapy with interferon-alpha and phosphodiesterase type 5 inhibitors

  • Diabetic papillopathy is a cause of chronic (possibly ischemic) optic disk swelling that generally has a better visual outcome

  • In patients taking amiodarone, an optic neuropathy that can be difficult to differentiate from nonarteritic anterior optic neuropathy can develop (albeit rarely); it typically affects both eyes simultaneously and has a more chronic course

• Posterior ischemic optic neuropathy

  • Involves the retrobulbar optic nerve and thus does not cause any optic disk swelling

  • May occur with severe blood loss or nonocular surgery, particularly prolonged lumbar spine surgery in the prone position

  • May be associated with dialysis

Diagnosis

• Clinical diagnosis (eg, visual loss accompanied by optic disease swelling, altitudinal field defect, crowded optic disk, temporal artery nodularity and tenderness, etc)

Treatment

• Emergency high-dose systemic corticosteroids

• Whether systemic or intravitreal corticosteroid therapy influences outcome in nonarteritic anterior ischemic neuropathy is uncertain

• Whether low-dose aspirin (~81 mg/day orally) reduces risk of fellow eye involvement is also uncertain

• Blood transfusion may be beneficial in treating marked anemia in patients with ischemic optic neuropathy who have undergone nonocular surgery