Answer:
A mistake in a contact lens prescription is a visual metaphor for Oedipus in "Oedipus Rex" by Sophocles (495 B.C.E. - 405 B.C.E.).
Specifically, Oedipus is mistaken about his self-identity. That his start point is off makes everything else off in his life. The same may be said of an individual whose contact lens prescription is incorrect.