In advanced age, the sealing off of the eyes is physiological. The body breaks down in many ways: the lungs are belabored, the legs struggle, the hands shake, and the hearing faculty becomes muffled. But we cannot resist a different reading when it comes to the eyes. We suspect that having seen too much over the course of a lifetime, they surrender themselves to darkness. Outer vision reaches its limit, and the time comes for inner vision to take over.
About a third of the way through the Odyssey, Homer springs a surprise when he suddenly introduces (at a banquet) an unnamed blind old poet. It’s himself, in his own story! This blind poet sees deep into the story he is telling, which is the same story in which he is being told. It is not so much a metafiction as it is a moment of double vision.