I am so very sorry Yorkieville 200. How-ever you did purchase a dog with a clear health guarantee that only covers genetic defects leading to death. You did knowingly sign this contract with this proviso; which is not btw a whole lot of a health guarantee.
Now having said this; I am so very very sorry for what you and your pup are under-going right now. This appears to be a rare condition.
You could take this up with the mother club;
www.ytca.org. And see if there could be any re-dress there with this breeder; if he/she is a member of the club.
I would have hoped that a show breeder, would have shown more compassion to you and your dog in this situation. Maybe offered you some re-compense for the medical bills.
Also there might be something that can be done if the breeders vet actually certified a clear health clearance, and your vet diagnosed this eye condition very early on when you first brought your pup to your vet. Something to consider.
Best of luck with your pup