As in Sophocles' play Oedipus the King, a major theme in William Shakespeare's play Othello is people's inability to reliably distinguish between what seems to be and what actually is. Explain how this shared theme of "uncertain vision" is treated somewhat differently in Othello than it is in Oedipus the King.
In both Sophocles' play Oedipus the King and William Shakespeare's play Othello, the main characters are, in part, led to their downfalls by their inability to distinguish reality from appearance and truth from falsehood. In both cases, the protagonists are not entirely to blame, as external factors as well as their own character flaws have led to their blindness; under normal circumstances, both of these men are good, even heroic, characters, which is why the "catastrophe" or reversal of their fortunes is tragic.
In the case of Oedipus, his blindness to the possibility that he himself is the murderer that he seeks is due to missing information. It is only when Jocasta and eventually the old shepherd reveal crucial pieces of information that it is possible for Oedipus to put all the pieces together. However, Oedipus himself is culpable in his own blindness in the intellectual pride that causes him to ignore the warnings of Tireisias who does state that Oedipus is the polluter of the city:
[Tireisias]: So?—I command thee by thine own word's power,
To stand accurst, and never from this hour
Speak word to me, nor yet to these who ring Thy throne.
Thou art thyself the unclean thing. Oedipus.
In Othello, the cause of Othello's blindness to the actual innocence of Desdemona is the passion of jealousy inflamed by the plotting of Iago. In one sense, his failure is a failure to judge character. He is blind to Iago's villainy and to the loyalty of Desdemona. Being overcome by the "green-eyed monster," he is not willing to seek alternative explanations for the observed facts.
Thus while Oedipus' inability to distinguish appearance from reality is due to intellectual pride and missing information, Othello's is due to emotion.