A blind dog whose owner didn’t know about her pet’s condition for nine months has been declared a “medical mystery” by veterinary experts. A border collie named Dave “never puts a foot wrong” and can even navigate around puddles despite his blindness, leaving vets completely baffled by his condition. A top UK vet has declared Dave a “medical mystery” after confirming that the dog is fully blind. Owner Jane Downes, 69, from Waterbeach, Cambs, said that her pet dog—who is believed to be between 5 and 7 years old—always comes when called and happily plays with other dogs despite his retinas being completely undeveloped. Jane and her husband, Mick, 78, said that Dave lives a happy and full life. “No one’s got any answers. It’s just a conundrum,” Said Jane, who’d owned Dave for almost a year before making the discovery. “It’s just really strange. He’s a blind dog that …