Walsh and Hoyt's Clinical Neuro-Ophthalmology

Ischemic Optic Neuropathy

"Ischemic syndromes of the optic nerve (ischemic optic neuropathy [ION]) are classified according to (a) the location of the ischemic damage of the nerve and (b) the etiologic factor, if known, for the ischemia."

"Ischemic syndromes of the optic nerve (ischemic optic neuropathy [ION]) are classified according to (a) the location of the ischemic damage of the nerve and (b) the etiologic factor, if known, for the ischemia. Anterior ischemic optic neuropathy (AION) includes syndromes involving the optic nerve head, with visible optic disc edema. Posterior ischemic optic neuropathy (PION) incorporates those conditions involving the intraorbital, intracanalicular, or intracranial portions of the optic nerve, with no visible edema of the optic disc. While several specific etiologic factors have been identified in ION, the most critical for initial manage- ment is the vasculitis of giant cell, or temporal, arteritis (GCA); therefore, ION is typically classified as either arteritic (usually due to GCA) or nonarteritic. Nonarteritic ION is most oftenidiopathic, but specific etiologies such as systemic hypotension and radiation injury have been identified. Finally, several syndromes of optic disc edema with relatively mild dysfunction, including preinfarct optic disc edema and diabetic papillopathy, are presumed to represent optic nerve ischemic edema with dysfunction that is not detectable, mild, or reversible."