I would argue that the central conflict is that of man vs. himself. Oedipus must battle his own impetuousness, hubris, and consequences of his actions.
To understand the ramifications, a reminder of how Oedipus came to be king at all is necessary.
Oedipus' parents, Lauis and Jocasta, have been warned by an oracle that their newborn son is destined to marry his mother and kill his father. In an effort to avoid their fate, the baby is abandoned on a hillside and left to die. He does not die, but is found and grows into manhood, completely ignorant of his real parentage.
As an adult, Oedipus meets with Laius on the road. The two fight and Laius is killed. Because he does not know Jocasta is his mother, Oedipus ends up marrying her and inheriting the kingdom. Jocasta, too, is unaware that Oedipus is her son. Their children, therefore, are the products of incest. The oracle is fulfilled despite the human attempts to foil the Gods.
Teiresias, the blind prophet, tries to tell the hubristic Oedipus that his life is not what he thinks it to be. He warns, "But I say that you, with both your eyes, are blind:/You cannot see the wretchedness of your life,/Nor in whose house you live, no, nor with whom."
When Oedipus finds out the truth, he blinds himself, thus fulfilling Teiresias' prophecy both literally and physically.