Regardless of the cause, ischemic optic neuropathy almost always occurs in those > 60 yr. Partial or complete loss of vision occurs suddenly, accompanied by swelling of the optic nerve head and often a hemorrhage or two. A visual field defect may produce a loss of half the visual field with a horizontal demarcation. Ischemic optic neuropathy is a medical emergency.
When temporal arteritis is the cause, tenderness along the temporal artery may be noted, as well as headache, jaw pain while chewing, and fever. Symptoms are almost always accompanied by an elevated erythrocyte sedimentation rate. Generally, prednisone 60 mg/day should be started as soon as possible, and a temporal artery biopsy should be obtained.
When atheromatosis is the cause of ischemic optic neuropathy, pain is uncommon, and decreased vision is soon followed by pallor of the optic disk. The visual loss in the other eye may occur months or years later, and once the ischemic episode has occurred, treatment does not help. In selected older patients with a history of blackouts (amaurosis fugax) suggestive of atheromatosis, long-term anticoagulant therapy may help.