Anterior ischemic optic neuropathy (AION) presents with a sudden loss of visual field (often altitudinal), usually involving fixation, in an older individual. The loss is usually stable after onset, with no improvement, and only occasionally, progressive over several days to weeks. In contrast to the hyperemic appearance that usually accompanies optic nerve head edema, pale disk swelling is present involving a sector or the full disk, sometimes with accompanying flame hemorrhages. The cup-to-disk ratio is typically small (0.1-0.2) bilaterally.
The common, nonarteritic causes of AION (probably arteriosclerosis) need to be differentiated from arteritic (AAION) ones, such as giant cell arteritis (GCA). If untreated, the latter will involve the other eye in 75% of cases, often in a few days to weeks. These elderly individuals often have weight loss, masseter claudication, weakness, myalgias, elevated sedimentation rate, and painful scalp, temples, or forehead.
Management and Disposition
Routine ophthalmologic and medical evaluation is appropriate.
Consider AION in an elderly patient with sudden, usually painless, visual field loss.
Rule out GCA. Patients tend to be older (age > 55 years) and may have associated CRAO or cranial nerve palsies (III, IV, or VI) with diplopia.
Anterior Ischemic Optic Neuropathy. Pale disk swelling and flame hemorrhages are present. This patient also has an unrelated retinal scar owing to toxoplasmosis. (Photo contributor: William E. Cappaert, MD.)
Nonarteritic Anterior Ischemic Optic Neuropathy (NAAION). Pallor of the entire temporal disk is seen in a patient with NAAION. (Photo contributor: Jeffrey Goshe, MD.)
Arteritic Anterior Ischemic Optic Neuropathy (AAION). Characteristic “pallid disk edema” of AAION in a patient with significant vision loss with confirmed giant cell arteritis. (Used with permission from The University of Iowa and EyeRounds.org.)