IFNG and COVID-19: SARS-CoV-2 RNA and SARS-CoV-2 S and nucleocapsid (N) proteins were detected in the eyes of patients who had recovered from COVID-19 (27, 28, 41), whereas IFN-γ, TNF-α, IL-5, IL-8, and granulocyte−macrophage colony−stimulating factor (GM−CSF) expression levels were significantly elevated in the tear film of patients with SARS-CoV-2 RNA-positive conjunctival swabs (27).