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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.
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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.
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Management and Disposition
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Routine ophthalmologic and medical evaluation is appropriate.
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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.
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