This is a really interesting question. It is easy to assume that our dogs see the world in the same way that we do, but in fact their vision is quite different to ours.
Is my dog colour blind?
To answer this question, we need to look at the structure of the eye. Light enters the eye through the pupil and hits the back of the eye – the retina. This light-sensitive layer contains cones, which are good at detecting colour and fine detail, and rods, which are better at detecting motion and vision in dim light. A dog’s retina contains a greater number of rods compared to a human retina, but only has approximately 1/10th the concentration of cones. This means that dogs are not able to see as many colours as humans, but they are better at detecting motion and seeing in dim light.
Due to the reduced number of cone receptors, dogs can only distinguish two colours – yellow and blue-violet, as well as shades of grey. Just like a colour-blind person, dogs are unable to recognise green, orange and red. Hence a blue or yellow toy is likely to be most visible to your dog, while a red ball may go unnoticed in the grass.
Interestingly, agility dogs perform best when poles and obstacles are painted in blue and yellow so that they can see them clearly. This helps them to navigate objects better and more accurately judge the distance between them.
Can my dog see in the dark?
Thanks to the higher concentration of rod receptors in your dog’s retina, they are much better at seeing in low light conditions compared to humans. They are also more sensitive to movement. These attributes make them perfectly suited to hunting at dawn and dusk, although they probably don’t do much of that nowadays!
How far away can my dog see things?
Dogs are generally thought to have 20/75 vision, compared to 20/20 vision in humans. This means that they are short-sighted in comparison to us – objects tend to become blurry for them the further away they are. They must be 20 feet from something to see it as well as a human standing 75 feet away. This visual acuity does vary between breeds though – for instance Labradors (which are commonly used as guide dogs) may have vision that is closer to 20/20. What dogs lack in their visual abilities they make up for with their amazing sense of smell and hearing, so these other senses tend to compensate for their poorer vision.
Do dogs have peripheral vision?
Dog’s eyes sit slightly further apart than humans and are also set at about a 20-degree angle, rather than facing straight forwards like ours. This means that they have a greater field of view compared to humans. While we can see around 180 degrees, dogs can see around 240 degrees (or 270 degrees for sighthounds!), giving them a more panoramic view and much improved peripheral vision.
The downside of this eye position is that a dog’s binocular vision (depth perception) is not as good as ours. This is because there is less overlap between the field of vision for each eye. They are not as good at judging distance as we are and do best when looking straight ahead. This does vary depending on breed, as the shape of the head and eye position is quite variable. This is one of the reasons that catching ability varies between dogs.