Blindness has been depicted by different cultures in a variety of ways throughout history. In Judaeo-Christianity, blindness was sometimes brought upon a person so that the mercies of God could be manifest in that person through a cure. The Ancient Greeks viewed blindness as a punishment from the gods, for which the afflicted was often granted compensation in the form of artistic genius or prophetic powers.
Something of the Greek tradition can be found in McCarthy's depiction of the blind maestro in Cities of the Plain, who if not quite a Tiresian prophet at least possesses a wisdom suggested as concomitant with his blindness.
The blind soldier in The Crossing is a different case altogether, and the story of how he came to his condition is related in a parable that owes as much to Nietzsche's abyss as it does to Plato's cave. The only secret knowledge blindness has imparted upon the ex-revolutionary is that all of humanity lives in a condition of 'ultimate sightlessness':
He said that the light of the world was in men’s eyes only for the world itself moved in eternal darkness and darkness was its true nature and true condition and that in this darkness it turned with perfect cohesion in all its part but that there was naught there to see. [p.283]