How such a character could see clearly through such a thick curtain of hair - as is usually the case - is most often completely ignored. It's a trope much more common in comics and animation than in live-action (since it's a bit hard for an actor to play while blinded by such a hairdo). This personal appearance trope can be used to convey various things. In western works, a character with such a hairstyle is often a bit of a dumbass you very rarely, if at all, see permanent Blinding Bangs on a personage with above-average intelligence. Since obscuring the eyes also obscures emotion, the character will usually seem a bit cool-headed, if not an outright stoic.
Also frequently used in Anime and Manga to illustrate a shy one - girls with this hairstyle are called 'maegamikko' or 'mekakure' in Japan. Unlike the temporary kind of face-concealing hair a character might have when depressed, Blinding Bangs are usually not a sign of depression, although perpetually mopey characters might also have them.