How is Tiresias’s physical condition an example of situational irony?

Tiresias' blindness, is ironic, because unlike Oedipus, he can see those things that Oedipus refuses to acknowledge. He also prophesizes that this man, Laios' murderer, will leave "blind, though now he sees - and poor, though now he's rich - he'll use a stick to guide his steps into another land...."