Being "blonde blind" refers to the tendency for many men to ignore or be oblivious to a woman's less-than-attractive facial features just because she has blonde hair. This blindness is especially profound when the woman also has large breasts or is wearing enough make-up to further the illusion of attractiveness. Often, prettier brunettes and red-heads are ignored by men altogether if these women are in the company of, or are in close proximity to, a girl with any shade of blonde hair, no matter what the blonde looks like facially.
Eddie could tell his jockish friends were blonde blinded by the girl sitting at the bar. They were ignoring the gorgeous brunette behind the counter just to ogle the bleach blonde with horse-teeth, a hooked nose, and way too much make-up.