Acute Ischemic Stroke in Non-Arteritic Anterior Ischemic Optic Neuropathy

Background: Non-arteritic anterior ischemic optic neuropathy (NAION) is a neuroophthalmological disorder characterized by impaired blood flow to the optic nerve head. There is uncertainty about whether, in some cases, NAION may be caused by proximal embolism of the posterior ciliary arteries. Diffusion-weighted magnetic resonance imaging (DWI-MRI) can provide evidence of concurrent cerebral infarction that may indicate a common embolic etiology. Methods: Adults with ophthalmological diagnosis of NAION who underwent cerebral DWI-MRI within 14 days from onset of visual impairment were included in a retrospective cohort study (2013-2021). DWI-MRI images were assessed for presence, location, and type of ischemic stroke by a board-certified neuroradiologist blinded for clinical patient data. Results: Among 122 patients (mean age 64.6 ± 11.9 years), DWI-MRI indicated acute/subacute ischemic stroke in three cases (2.5%), all located within the anterior circulation in the territory of the left middle cerebral artery and ipsilateral to the affected eye in two cases (1.6%). Ischemic stroke location was cortical in one case (0.8%) and subcortical in two cases (1.6%). Acute ischemic stroke indicated by a hyperintense DWI signal and corresponding low ADC was present in one patient (0.8%). Two patients (1.6%) had subacute ischemic stroke (hyperintense DWI signal and normal or elevated ADC signal). Only one NAION patient (0.8%) had acute embolic stroke corresponding to the vascular territory of the affected eye. Conclusions: Concurrent embolic ischemic stroke in NAION is exceedingly rare. Our findings support the prevailing pathophysiological theory of NAION as a non-embolic disease.