This statement turns out to be true when Oedipus finally does see that his entire life was nothing like he had thought.
The inability to see would make someone blind, but to be blind in this play does not mean one is physically blind, rather that he/she is unable to see the truth about things. Though Oedipus is not physically blind, he is blind from the truth about his life, believing that he actually had avoided the oracles prediction of his fate. Teiresias describes Oedipus by saying with your precious eyes, youre blind to the corruption of your life (1141-1142). When saying this, he means that Oedipus is completely unaware of the fact that he actually did kill Laius, his father, and that he is married to his mother. Oedipus tries to explain Tiresiass lack of knowledge by saying that he has lost his power and is stone-blind, stone-deaf - senses, eyes blind as stone (1140). By saying this he is implying that the prophet knows nothing and he knows everything, which is not true. This is another example of dramatic irony because it is the blind man who has the ability to see. When Oedipus finally realizes the truth, the chorus explains that its better to die than be alive and blind (1168), meaning that if he has to live with all of the truth he will bare much more suffering than he would if he were to die. This relates back to Tiresiass statement which said the truth will cause Oedipus pain.
Similarly to the motifs of sight and blindness, light also represents knowledge and understanding of the truth. When first realizing that he needs to do something about the plague, Oedipus says that he will bring it all to light (1134), essentially saying that he will bring out the truth of the problem and put an end to everyones suffering. When Tiresias tells Oedipus the truth about his life, Oedipus says to him, you cant hurt me or anyone else own sees the light (1140), explaining that Oedipus knows the truth and the words of the prophet will not change that.
