Thanks for sharing that wonderful story. It gives me hope for my girl T. She is slowly losing her eyesight, and from what the vets have said, will adjust beautifully. It is harder on humans than animals. She will except it and adjust. Having Walka with her is comforting to her though. He looks out for anything that might be a concern and she relies on him more. Riding, you would never know she has diminished sight. She had a few stumbles at first, but quickly adjusted to the loss of depth perception. I at first would use a half halt to cue her to the change in terrain. Now, I don't have to do even that.
Don't sell a blind horse short. And don't judge what you think their life is by our standards. They learn their area very well and are quite content and happy. If and when my girl shows me otherwise, then I'll do what is best for her, but I'm not about to jump the gun and assume she's done and put her down. That's just my feelings on it.
I keep thinking of John Lyons stallion Zip, who lost his sight very abruptly. He adjusted so well, and they enjoyed riding for years after. A lot does depend on the temperment of the horse, and in that case, like Zip, T will be fine. She has always been sure and steady. A thinking horse.
Be the kind of woman that when your feet hit the floor each morning the devil says, "Oh crap, she's up!".