Anterior ischemic optic neuropathy (AION) is the most common cause of acute optic neuropathy after age 50, but may also occur in younger patients. The diagnosis is clinical and includes painless visual loss associated with a relative afferent pupillary defect and disc edema. In almost all cases, there is an underlying crowded optic nerve with a small cup-to-disc ratio. The visual prognosis is usually poor, although up to 43% of patients may improve over time. The fellow eye is involved in up to 15% of patients within 5 years, but the risk of recurrence in the same eye is less than 5%. There is no treatment for acute nonarteritic AION but it is essential to evaluate these patients for underlying treatable atheromatous vascular risk factors. A coagulation workup should also be considered in younger patients. It is essential to rule out giant cell arteritis in all patients over the age of 50 with ischemic optic neuropathies. Posterior ischemic neuropathy (in which the optic nerve is normal acutely) is rare and should be considered a diagnosis of exclusion.
From the Departments of *Ophthalmology, †Neurology, and ‡Neurological Surgery, Emory University School of Medicine, Atlanta, Georgia.
Supported in part by a department grant (Department of Ophthalmology) from Research to Prevent Blindness, Inc., New York, New York, and by a core grant P30-EY06360 (Department of Ophthalmology) from the National Institutes of Health, Bethesda, Maryland. Research to Prevent Blindness Lew R. Wasserman Merit Award (to N.J.N.).
Reprints: Valérie Biousse, MD, Neuro-Ophthalmology Unit, Emory Eye Center, 1365-B Clifton Rd, N.E. Atlanta, GA 30322. E-mail: firstname.lastname@example.org.