Bought dog from breeder,pet smart vet said dog was good found out later dog blind had to euthanize

I'm not sure why you had to euthanize the dog because of blindness, but in any event, look at the documents that you got form the Pet Smart Vet to find out if you can get your money back for their treatment or evaluation of your dog.  I've never used Pet Smart for this purpose, but I would suspect that they make you sign all kinds of disclaimers before they examine your dog indicating they will not be responsible for any undiagnosed conditions, etc.  Also if the breeder gave you any documentation about the dog, or warranted that the dog was healthy or had been properly vaccinated, then you might be able to get a refund of the purchase price, or first option on a new puppy.  Good luck.