Monocular Superior Altitudinal Field defect due to Supraclinoid Internal Carotid Artery Aneurysm

An altitudinal visual-field defect is confined to the upper or lower half of the visual field but crosses the vertical median. Slight arteritis usually causes ischemic optic neuropathy, with a compressive lesion causing optic neuropathy in rare cases. We report a 46-year-old woman with a monocular superior altitudinal visual defect due to an aneurysm in the supraclinoid portion of the internal carotid artery. It appeared that the ipsilateral cerebral aneurysm compressed the optic nerve and secondarily caused posterior ischemic optic neuropathy.