Sidney Bradford went blind at 10 months of age, but regained sight on both eyes at 52.
He was subjected to many scientific studies of vision, that demonstrated that he was impervious to many form of optical illusion, like the ambivalence of necker cubes or the appearance of various "impossible objects" that, to him, looked like what they are - flat figures.
However, his regaining the gift of sight left him with the vision of a world he did not know, and he preferred to work with his eyes closed, so that his hands could "see" his familiar tools.
Two years after regaining sight, he fell ill and died. Blind, he knew the universe where he lived intimately, and was a happy man.
When he finally saw the world, its sheer incomprehensibility killed him.
Let's be honests...
We understand him plenty.