Asymptomatic optic disc edema.
Non-arteritic anterior ischemic optic neuropathy (AION-na) classically presents with visual loss, altitudinal visual field defects, and optic nerve swelling. AION-na presumably occurs secondary to an ischemic event. Two patients are described who were at risk for developing AION-na. Both patients presented with optic disc edema but did not have visual loss or visual field defects. Neither patient developed visual loss or visual field defects in the affected eye throughout one and two years of follow-up respectively. The optic disc edema resolved spontaneously in both affected eyes. The clinical spectrum of AION-na could range from a "full-blown" classic attack to a minimal attack characterized by disc swelling without visual loss. The amount and distribution of disc ischemia determines the individual clinical picture. The failure of either affected eye in this study to develop symptoms likely represents a graded axonal atrophy with mechanical decompression of the optic nerve.