To report a rarely isolated central retinal artery occlusion (CRAO) following Coronavirus disease 2019 (COVID-19) Vaccine Moderna (mRNA-1273).

A previously healthy 70-year-old man presented with acute painless visual loss of the right eye five days after the first dose of Moderna vaccine. On examination of the right eye, visual acuity (VA) was counting finger at 15 cm. Fundoscopy revealed a diffuse whitened retina with cherry-red spot. Optical coherence tomography (OCT) showed hyperreflectivity. Screening tests for platelet and D-Dimer levels were unremarkable. CRAO was treated with clopidogrel and hyperbaric oxygen therapy. The serum level of anti-platelet factor-4 (PF4) antibody was 73.34 ng/ml (ref, 0-49.99 ng/ml).Two months later, VA was counting finger at 10 cm and OCT revealed hyperreflectivity and mild inner retina atrophy

COVID-19 vaccine-induced thrombosis and thrombocytopenia (VITT) based on the victims receiving AstraZeneca and Johnson & Johnson vaccines is through autoimmune antibody against PF4. VITT is typically manifested within 6-24 days post-vaccination; thrombotic sites are in the cerebral sinus, portal vein, splanchnic vein, and pulmonary emboli; as well as thrombocytopenia and increased level of D-Dimer. Our patient had isolated CRAO five days post-Moderna vaccination but normal platelet count and D-Dimer level. Moreover, VIT with isolated CRAO was not published on PubMed.

VIT could occur in the unusual site such as CRAO in our case. Normal platelet and D-Dimer levels might not be sensitive tools to exclude VIT. Suspected patient with thrombotic event after COVID-19 vaccines should have anti-PF4 antibody test to assure an effective treatment.