TY - CHAP M1 - Book, Section TI - Anterior Ischemic Optic Neuropathy A1 - Effron, David A1 - Forcier, Beverly C. A1 - Wyszynski, Richard E. A2 - Knoop, Kevin J. A2 - Stack, Lawrence B. A2 - Storrow, Alan B. A2 - Thurman, R. Jason PY - 2021 T2 - The Atlas of Emergency Medicine, 5e AB - 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. SN - PB - McGraw-Hill CY - New York, NY Y2 - 2024/10/15 UR - accessemergencymedicine.mhmedical.com/content.aspx?aid=1181039706 ER -