Atypical Posterior Reversible Encephalopathy Syndrome Following COVID-19 Vaccination

Purpose: This report describes a visual field defect associated with atypical posterior reversible encephalopathy syndrome (PRES) after coronavirus disease 2019 (COVID-19) vaccination.Case summary: A 25-year-old man presented with visual field defects in both eyes 1 week after COVID-19 vaccination. He had brief chest discomfort following the vaccination. His best-corrected visual acuity was 20/25 in both eyes without relative afferent pupillary defects. The color vision test was normal. The Humphrey visual field test showed a bitemporal visual field defect respecting the vertical midline. A slit-lamp examination revealed no abnormality in the anterior eyes. Funduscopic examination revealed no abnormalities in the posterior parts of the eyes, including the optic discs. Orbital and brain magnetic resonance imaging were normal. Hematological tests, including two auto-antibodies related to optic neuritis (myelin oligodendrocyte glycoprotein and aquaporin-4 antibodies) were normal. Two months after the initial symptoms, the visual field defects had improved. At the 6-month follow-up, there was more improvement. Atypical PRES was diagnosed.Conclusions: Patients may develop visual field defects due to encephalopathy following COVID-19 vaccination. A detailed history and proper imaging studies are needed to diagnose PRES.