Happy birthday, sir! If you can shoot out to 20 yards, you are good to go for hunting. Hopefully, the doctor can do something to improve your vision. If not, perhaps pre-measuring distances, as suggested by Bvas, will help.
I don't blame you for staying out of trees. I have had several falls lately, myself. Fortunately, I haven't fallen out of a tree stand, but I have busted my butt a time or two.
I'm glad to hear that the ghillie suit is working well for you. I have a ghillie, but am not really comfortable shooting the bow with it, though. It is amusing that you say that you sometimes have to allow deer to walk away to have room to set up a shot. The ghillie is sure working for you.