Nonarteritic Anterior Ischemic Optic Neuropathy following COVID-19 Vaccination: Consequence or Coincidence

To report a patient with nonarteritic anterior ischemic optic neuropathy (NA-AION) occurring soon after the COVID-19 vaccination. A 55-year-old woman presented with a 4-day history of inferior visual field disturbance in the right eye 7 days after receiving the first dose of Pfizer-BioNTech COVID-19 vaccine. Examination revealed a best-corrected visual acuity of 20/20 in both eyes. A relative afferent pupillary defect was observed in the right eye. Fundoscopy revealed diffuse optic disc swelling in the right eye, which was prominent above the optic disc. Goldmann visual field testing identified an inferior altitudinal visual field defect with I/2 isopter in the right eye. Although typical complete inferior visual field defect was not detected, a diagnosis of NA-AION was made. The patient was followed without any treatment. During the 2-month follow-up period, the optic disc swelling was gradually improved, and visual acuity was maintained 20/20; however, the optic disc looked diffusely pale in the right eye. Although it is uncertain whether the development of NA-AION after COVID-19 vaccination was consequential or coincidental, we speculate that the close temporal relationship with COVID-19 vaccination suggests the possibility of vasculopathy on the microvascular network of optic nerve head as background of inflammatory or immune-mediated element to the timing of the onset of NA-AION. The aim of this case report is to present this biological plausibility and to elucidate potential ophthalmological complications.