PURPOSE: To describe the occurrence of anterior ischemic optic neuropathy in a young woman with internal carotid artery hypoplasia, METHODS: Case report with clinical and radiologic observations, RESULTS: A 38-year-old woman suffered from a sudden, painless loss of vision in her right eye. The diagnosis of anterior ischemic optic neuropathy was based on the clinical course and appearance of the fundus, Doppler evaluation of the carotid arteries, computed tomography (CT) scan, magnetic resonance imaging (MRI), and CT angiogram all demonstrated internal carotid artery hypoplasia on the same side, CONCLUSION: Although carotid artery disease (mainly atherosclerosis) is not a common predisposing factor for anterior ischemic optic neuropathy, our patient had an ipsilateral coexisting internal carotid artery hypoplasia and anterior ischemic optic neuropath. We believe that the carotid artery anomaly might have contributed to the development of anterior ischemic optic neuropathy in this patient. (C) 2001 by Elsevier Science Inc. All rights reserved.