My cat has a lot of eye discharge and can't open their eyes — is it conjunctivitis or herpesvirus?

Quick answer

If yellow discharge builds up frequently along with red eyes, sneezing, and a runny nose, it's likely an infection with the herpesvirus (FVR) — often called 'cat flu.' Once infected, it can't be fully cured; the virus lies dormant in the body and can flare up again during stress or lowered immunity. Prescribed eye drops and immune-support supplements (like L-lysine) can help.