Oedipus' decision to blind himself is very symbolic. Because of his hubris, he was blind to all of the warning signs about the path he was travelling. He refused to see. In the end, when all is brough to light, he blinds himself, so he finishes the play literally as blind as he figuratively was throughout.
He is unable to avoid the fate that had been foretold for him from his birth. He also brings curses upon himself, by cursing the murderer of Laius. His self-punishment reveals that he believes his suffering is deserved. It is his attempt to bring justice to the situation.