Blind as Tiresias. Tiresias the Theban by accident saw Athena bathing, and the goddess struck him with blindness by splashing water in his face. She afterwards repented doing so, and, as she could not restore his sight, conferred on him the power of soothsaying, and gave him a staff with which he could walk as safely as if he had his sight. He found death at last by drinking from the well of Tilphosa.
Juno the truth of what was said denied, Tiresias, therefore, must the cause decide.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894