I have a pony with bad arthritis so moment is difficult for him and he can't do as much anymore. To keep him active and learning I've been teaching him tricks. To smile, bow, give kisses, raise feet when I tap them, and follow me without a lead line. This gives him little things that he can do that still make him feel important. I recommend you try to see what your horse can do with his eye sight then teach him fun little things that would be a great showcase infront of an audience. Something like, "oh my horse can do this!" Sorry of thing.
Hello Emily, what do you mean by "can't do what he loves?"
Anyway if he can see ok, you can continue to work as usual right ? :)