People get red eyes because marijuana causes the blood vessels in the eyes to enlarge. Your eyes aren't really red its just the blood vessels becoming more visible. You say that you have never gotten red eyes but you probably have you just don't notice it. I used to think i never got it, until one day i was nonchalantly eating lunch (blazed of course) and my mom told me my eyes were i red as the shirt i was wearing. Needless to say, she knew why.

P.S. The answear is directed to the question posted by 420purplehaze420