I have taught several blind people to ride and apart from small allowances, have the belief that they can rode as well as a sighted person.
The first two were children, a boy of a out 10 and his older sister who was 12. I never started them in an arena or on the lunge but ponied them from a good hunter and they were riding suitable ponies. The hardest thing to teach them was trot rising, (this was only after they achieved a good sitting trot) the rest was just as it would be for any other child I was teaching,
When it came to arena riding I would use four bleepers that emitted different signal tones. This enabled them to know when they were coming to corners
As soon as they were in control, had good strong seats, they were out on the trails off a lead. I always gave warning of things ahead, often forgot to tell them to duck if I went under a low branch.
The girl was far more enthusiastic and, with verbal help she could complete a round of show jumping and we even competed cross country in a pairs class.
She did have the most fantastic pony that seemed to understand her disability.