Kellar the 3-year-old English Springer was born completely blind, but that doesn't slow him down when it comes to playing fetch.
He can smell his toys, and he also responds to verbal commands. His owner explains on YouTube:
"Kellar was originally trained to play ball with the commands 'hot' and 'cold.' We later added 'warmer,' 'passed it,' 'left," and 'right.' The process took about a week for the basic commands."
Very impressive! But, as you can see in the video, Kellar sometimes doesn't need any help at all.