Do dogs only see in black & white?
PUBLISHED: 16:25 05 January 2021
© © J., M., O. & A. Redmond
Vet Vicky Payne explores canine vision, from the misconception that dogs see in black & white, to the eye problems dogs are prone to
Nothing beats the gaze of a devoted gundog — except maybe that steely stare when they mark the fall of a bird and you just know they will go straight to the spot and pick it successfully. But, have you thought about how a dog’s sense of vision is different to our own?
It is now known that dogs do not see in black and white, but they do only have two types of colour-detecting cone cells, compared with three for humans. It is more accurate to think of them as red/green colour blind. Red, orange, yellow and green all look like yellow to a dog, but they can see blue and purple tones; this can be used to your advantage in training.
I use orange dummies for blind retrieves in experienced dogs, so I can give the dog the correct direction, but the dog can’t spot the dummy and must trust me. I use blue to encourage puppies to run out, as the colour stands out from the grass. I also wear purple gloves when shooting to help my dogs spot me!
Field of vision
As predators, dogs have their eyes on the front of their heads, but the angle means they still have better peripheral vision than humans, allowing them to see us from the corners of their eyes when they are in front of us.
They have the binocular vision vital for depth perception, but their long noses can get in the way!
Dogs don’t have the same level of visual acuity as humans. They are good at spotting movement due to a large number of rod cells in the retina, but they can only see at 20 yards what a human could at 75 yards. This makes the feats of handling, which some retrievers perform at over 100 yards from their handlers, even more impressive!
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While dogs can’t actually see in the dark, they do have more rods than us, which means they see better in low light. They also have a reflective layer, called the tapetum lucidum, which reflects light. However, this does mean that their daytime vision is like a TV with the brightness turned right up.
It’s all about the eyes
Experiments with dogs and wolves have shown that they will follow the gaze of another dog, wolf or human more than their body language. In one experiment, the handler pointed at one of two pots, which may have had food underneath. Dogs chose to investigate the pot that the human looked at, regardless of which pot they had pointed at.
Most gundog breeds will suffer from one or more inherited eye diseases. Gundog breeders can make use of the KC/BVA eye-testing scheme and DNA tests to reduce the risk of producing affected puppies.
The KC/BVA test should be performed annually for breeding dogs and looks for changes in the retina and the lens. Some breeds, including English springer spaniels, should also be tested as puppies, as some conditions can ‘go normal’ as the dog grows, only to return in later life. The specialist vet will also take note of any abnormalities of the eyelid, such as entropion or ectropion, which have sadly been common in Clumbers and Sussexes in the past.
The KC/BVA eye scheme also covers goniodysgenesis, which increases the risk of glaucoma. Breeds, including flat-coated retrievers, cockers and springer spaniels, should be tested every three years.
Eye injuries are common in working dogs, and any difference in pupil shape, a bulging or painful eye should prompt an immediate trip to the vet. However, loss of sight isn’t always a problem for dogs, as they learn to use their other senses. It has been known for owners to only discover their dog is blind when they move the furniture!