I have a foster with Progressive Retinal Atrophy. He was seen by the vet opthamologist and nothing could be done to help him. He has lost his sight, but is doing well. He knows where everything is in my home and gets around fine.
It is a sad thing for us to watch, but these little guys do handle blindness well. One of my personal pups is blind and deaf and he also does well.
There is a book that might help you: Living with Blind Dogs