To the Editor.
—The otherwise excellent article by Guyer et al1 was flawed by the recommendation that tests for carotid artery patency be performed on patients with anterior ischemic optic neuropathy (AION). Such tests may lead to invasive procedures and expose patients to the unnecessary risks of intra-arterial cerebral angiography2 and ultimately carotid endarterectomy for asymptomatic carotid stenosis.3,4The retrolaminar portion of the optic nerve seems particularly vulnerable to ischemia from local mechanical factors5,6 and small-vessel disease.7,8 Indeed, a similarity between AION and hypertensive lipohyalinotic cerebral angiopathy, which causes lacunar strokes, not strokes resulting from extracranial carotid disease, has been suggested.8I am unaware of any evidence linking AION to extracranial carotid disease, except in the rare instance of internal carotid artery occlusion where AION is part of ischemic oculopathy, or with central retinal artery occlusion involving the optic nerve head.The case for
Lavin P. The Role of Carotid Endarterectomy in Ischemic Optic Neuropathy. Arch Ophthalmol. 1985;103(11):1633-1634. doi:10.1001/archopht.1985.01050110027011