How does the images of vision and blindness relate to the theme of the Oedipus Rex?

I think that this becomes the most important element of
the drama.  Oedipus, with sight, wanted to know the truth, to "see" it all and commanded
everyone, including Chorus members, to disclose what they know.  In many respects, this
desire to see caused his blindness.  When he is confronted with the results of his
demands, it becomes too much and he blinds himself.  The act of blinding himself causes
him to "see" more than he was able to with eyesight.  Through his blindness, he is able
to see that his children (actually his siblings) will suffer more in their lives because
of actions that are not theirs.  He also sees that their lives' difficulty has to prompt
pity from the citizens of Thebes.  More importantly, Oedipus sees his own reality, not
as a king, but as a human being.  His desire to be exiled and live a humble life, in
constant pain and seeking to minimize it, is an element that he sees only after his
blindness.  It is through this action of becoming blind is Oedipus able to understand
that humility that is intrinsic in being human, something he was unable to see with
physical sight.