In broadest terms, light and darkness correspond to knowledge and ignorance or concealment of it. Sight is particularly important in reference to the metaphorical acknowledgment of confrontation of knowledge, and literally in reference to Oedipus’ final act of blinding himself. Several characters take deliberate actions to conceal information or not to face the consequences of actions, while others are affected by their lack of knowledge.
Tireisias, who is physically blind but gifted as a prophet, embodies the contradictions of light/dark, sight/blindness. He deliver the lines that tie together these themes:
But I say that you, with both your eyes, are blind:
You cannot see the wretchedness of your life….
Oedipus, who is unaware of having fulfilled the prophecy, is likewise ignorant of the consequences of his actions. In refusing initially to believe Tireisias, he uses a “lost in the night” metaphor for physical blindness and his apparent lack of knowledge. Nevertheless, as a noble heroic figure, he accepts responsibility and finally blinds himself and voluntarily goes into exile.
Jocasta is in the light because she is knowledgeable about the prophecy, but lives in shadow because she abandons her child. Her enlightenment comes at the cost of her life, as she bears the burden of trying to avoid what the gods ordained.