According to the literary department of Ball State University, although Oedipus is not truly responsible for the murder of his father and marriage to this mother, he is the instigator of his own blindness and exile. It is Oedipus's own actions that set the prophecy in motion.
The narrative of "Oedipus Rex" leads the reader to understand that there was no way for Oedipus to escape the prophecy that he would murder his father and marry his mother. The literary value of "Oedipus Rex" lies in the ambiguity of the extent to which Oedipus is truly responsible for his fate.
His pride causes him to disregard the warnings of the prophet Tiresias not to investigate further the matter of King Laius' death. The prophecy did not say that Oedipus would live in dethronement, exile, blindness and with the death of his wife/mother on his mind. Oedipus causes those specific details to occur.