It's kind of hard to miss the motif of blindness in the story of Oedipus, especially if you read Sophocles' version, Oedipus the King. The two literal examples of blindness in the story are the blind seer Tiresias and Oedipus when he stabs out his own eyes. What's interesting about this pairing is that though Tiresias is literally blind when he comes before Oedipus, he can see the truth of Oedipus all too clearly. Later on, when Oedipus finally sees the truth, he can't take it and blinds himself. In the end, you could see Oedipus as being symbolic of all humanity, trying to feel his way though a dark and unknowable universe. For a thorough discussion on the way Sophocles uses the motif of blindness in Oedipus the King click here.