There are many images of eyes and references to sight, many of which are used with unconscious irony by Beatrice, who points out that the eye can deceive when it comes to reaching reliable judgments about love and character. In act 1, scene 1, she says to Alsemero:

Our eyes are sentinels unto our judgements,

And should give certain judgement what they see;

But they are rash sometimes, and tell us wonders

Of common things, which when our judgments find,

They can then check the eyes, and call them blind.

Beatrice says of her quickly forgotten love for Alonzo, "Sure, mine eyes were mistaken," and she contrasts the superficiality of the eyes with what she calls the "eye of judgment" and "intellectual eyesight." The irony is that Beatrice is never more blind than when she thinks she is seeing with the eyes of judgment.

Images of sickness, poison, and blood...