Seven is not at all old for a yorkie, and usually dogs that gradually lose vision adapt well. I would be more suspicious of a health issue and have him checked out thoroughly by your vet, especially as he has a history of a back issue. I have an 8 year old toy poodle that has had a few problems with his back/neck. The first sign is generally crying out unexpectedly, maybe just a yip if he turns his head suddenly. It seemed random at first, but now we know that's how he shows his neck is bothering him. A short course of prednisolone and some crate rest and he's back at it. Dogs don't always show pain in ways that we can easily interpret. Hope this helps.
Diana |