How do the ideas of blindness and sight correlate to the ideas of knowledge and ignorance throughout the play in Sophocles' Oedipus Rex?

In the play
, it is ironic that those without sight can "see" the truth, but
those with sight are often "blind" and/or ignorant to the truth. Therefore, sight and
knowledge are directly and ironically related.

For example, the character, ,
a blind prophet who is knowledgeable concerning the fates of others, knows the truth concerning
's fate. Tiresias reveals a prophecy which states that Oedipus will kill his father and marry
his mother. Despite the fact that he is blind, he can "see" what others cannot
concerning their lives.

Additionally, one will notice that Oedipus, once he
discovers the truth, blinds himself. This is another example displaying the correlation between
sight and knowledgeonce Oedipus is aware that the prophecy was fulfilled, he rids himself of his
sight. Oedipus now sees the truth but cannot literally see.