How does Sophocles use the sense of sight to create dramatic irony and tension?

Oedipus seems like an intelligent guy but he just didn't believe in fate. The ancient Greeks were all about fate. So when he doesn't listen to the oracle about his family, he never sees the truth when it is plain to see. So, he ends up marrying his mother and killing his father. All this gets him is wandering around with gouged out eyes and feeling really creepy. He never saw the truth when he could see but could see the truth in his blindness. It's dramatic irony because, by the end of the play, the audience can tell Oedipus, "We told you so!"