An incredible dog whose owner didn't know he was blind for over nine months has been declared a "medical mystery" by a veterinary expert.

Border Collie Dave "never puts a foot wrong" and can even navigate around puddles despite his blindness-leaving vets completely baffled.

Jane Downes, 69, says that her pooch has always come when called and happily plays with other dogs despite his undeveloped retinas leaving him completely blind.

Believed to be five or seven years old, Dave had been with Jane for almost a year before she made the discovery.

"No one's got any answers. It's just a conundrum and really strange."

"He's a blind dog that can see. Maybe it's a sixth sense, who knows?"

Jane bought Dave from an animal rescue centre in February 2020, when no issues were raised regarding his sight-even after a check-up at the local vet.

Jane, from Waterbeach, Cambs, said, "He jumped into the back of the car and I brought him home."

"On a couple of occasions he walked into things but I put that down to him being a sheepdog who more than likely lived in a barn rather than a house."

When Dave stumbled over a step at a pet shop in Cambridge, the owner suggested to Jane that her dog might be blind, so she took him to a specialist vet.

Turns out, Dave had been sightless from birth.

After the revelation, Jane called on the help of Cambridge University's David Williams, a top veterinary ophthalmologist, who organized two obstacle course challenges for Dave.

He told a local newspaper: "I see a lot of blind dogs and they all bump into objects in a way that Dave didn't-so at present he is a medical mystery. Just because I've been doing this for 33 years, it doesn't mean I've seen everything, and this I can't explain."

Dave now enjoys running around at home with his new brother Sammy, a two-year-old Border Collie, who joined the family last year.

"He chases other dogs around, even though he can't see them," says Jane.

"He had everyone fooled-even me as his owner I was fooled for nine months."

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