Teiresias is blind, but sees. Oedipus has eyes, but is blind. In the play, how is this defined?

Teiresias holds the key to the link between sight and blindness - for even though he is blind, he can still see and predict the future (if not the present). At the end of the play, moreover, Oedipus blinds himself, because what he has metaphorically seen (i.e. realized) leaves him unable to face his family or his parents in the afterlife). As with the previous theme, sight/blindness operate both literally and metaphorically within the play. Indeed, literal sight is juxtaposed with 'insight' or 'foresight'.