Fun fact June 16, 2021.

Are you Argus-eyed?  You may be, and not even know it.  Let’s see if I can clear up any confusion.  If you are Argus-eyed, you a vigilant.  You have a keen eye.  You are watchful.  According to Lexico dot com this idiom comes from Argos, the Greek mythical giant watchman who had 100 eyes.  His surname, Panopes, means the all seeing one.  With 100 eyes, I guess he was.