My father is blind. Macular degeneration, one of Fate's nastier jokes (as he has been an artist and designer his entire life)--the "wet" variety. MD knocks out central vision, leaving the afflicted person with some peripheral vision; over the years Dad, for whom vision and perception were professional preoccupations, has made all sorts of observations about his condition, and even wrote a book which he has self-published as Vision Junkie: Confessions of a Macular Degenerate.
(You will note that blindness has not affected Dad's delicate sense of humor.) He has learned to navigate the world using that peripheral vision--if he wants to see the face of one of his granddaughters he sort of cheats the kid to the side and moves his head and rolls his eyes until he gets some sort of fix on her, sideways.
So I get a call today. Two pieces of good news: the first, and fairly astonishing, is that he has been growing new cells in the "dead" areas of the macula. They're not even sure what this means, but it's exciting. The second is that for the first time in several years Dad was able to read the first three lines of a visual acuity test (a more elaborate version of the stacked-letter test we know from the optometrist). He's pretty sure he did that with his peripheral vision, which he has been exercising in his own way. So as usual he has all the doctors hopping up and down. He's pretty damned pleased himself.