The audience does not see Jocasta commit suicide or Oedipus blind himself, because in Ancient Greek theater such violent catastrophes traditionally happen offstage. The audience hears them described by witnesses rather than seeing them firsthand. Greek tragedy left more to the imagination than modern theater does. It placed a great deal of importance on the language in which the catastrophe is described. In the case of Oedipus, the convention of keeping violence offstage is thematically appropriate. The audience is faced with the realization that it is blind, that it relies for its knowledge of events on report and hearsay, and is thus prone to error and uncertainty. Over the course of the play, the once-confident Oedipus discovers that he is in the grip of uncertainty and error himself. His self-blinding symbolizes, among other things, the blindness and doubtfulness of human life in general.

The messenger suggests that the Chorus—and, implicitly, the audience—is better off having been spared these terrible spectacles, and his words guide the audience’s reaction. When the messenger describes the wrenching sobs that Oedipus delivers upon seeing Jocasta, our emotions are stirred in a different way than if we had simply witnessed the violence ourselves. The focus is on the other characters’ reactions to the violent acts, and on the audience’s reaction, instead of on the acts themselves.

In Oedipus at Colonus, Oedipus is almost utterly dependent on his two daughters, Antigone and Ismene. Antigone acts as Oedipus’s eyes and Ismene as his ears. When they arrive at the sacred grove at Colonus, Oedipus asks Antigone to leave him and find out if anyone lives nearby, and she says that she can see a man approaching. Oedipus cannot tell that the citizen has exited until Antigone tells him so. Antigone also first perceives the approach of the Chorus, Ismene, Creon, and Polynices, and she repeatedly helps Oedipus move around the stage. Oedipus’s reliance on his daughter for her sight emphasizes both his blindness and his impotence, as well as the strength of his relationship with Antigone. Given Oedipus’s faltering and lack of self-reliance in these early scenes, the messenger’s description of Oedipus proceeding unaided to the spot where he dies seems miraculous.

Ismene is not nearly so close with her father, as the fact that she is not so helpful with respect to Oedipus’s most terrible loss—his sight—indicates. Ismene’s first lines are about her not being able to see her father and sister through her tears. Immediately thereafter, she exclaims that she can hardly bear to look at her father because of the cruel fate that he has suffered. Ismene is distracted by pity and shame in a way that Antigone is not. Nevertheless, Ismene does offer practical help to her father, and it is from her that Antigone and Oedipus learn that Creon and Polynices, separately and on the advice of the oracles, seek Oedipus’s blessing and body to aid them in their battles for control of Thebes. It is also Ismene who goes to perform the rites of atonement to appease the spirits on whose ground Oedipus and Antigone trespassed at the beginning of the play.