How Well Can Dogs See?
We know that dogs have great noses, but what about their eyesight?
Although there are similarities in the anatomy of dog and human eyes, dogs also have eye structures that people lack that, for example, allow them to see better at night, (and eyes that appear to glow at night). Dogs also have a third eyelid, known as the nictitating membrane, located at the corner of the eye, near the nose. It helps protect the eye from scratches and also moves across the eye when a dog blinks to help produce tears.
The iris, or coloured part of a dog’s eye, can be brown, blue, golden, or hazel. Brown is the dominant color for most dogs. Dogs can have two different-colored eyes, which most often occurs in dogs with a merle coat pattern, or in certain breeds such as Huskies or Australian Shepherds.
If a dog has light-colored (blue) eyes, it does not mean that they will have vision problems, blindness, or any other health concerns. The iris pigmentation can vary depending on breed, color of the face, and genetics.
Dogs cannot see objects as well as humans. Normal human vision is 20/20. Most dogs have a visual acuity of 20/75, meaning a dog has to be 20 feet away to see an object as well as a person can see at 75 feet away. Some breeds such as Border Collies and Labrador Retrievers, have better eyesight that is closer to 20/20. A dog’s vision is blurry. If a dog were a human, they would be considered near-sighted and would need glasses to see objects farther away.
How Well Can Dogs See Moving Objects?
Dogs have more rods in the retina than humans do. Rods are sensitive to shape, movement, and dim light. They can see moving objects much better than stationary objects, and they have 10-20 times greater motion sensitivity than humans. Dogs can pick up on small changes in body posture and movement as a result. This is one reason why dogs can be trained with silent cues using hand gestures.
Can Dogs See in the Dark?
Dogs have several anatomical advantages that allow them to see better in the dark than we can:
- More rods in their retina, which function better in dim light
- Larger pupils that allow more light into the eye
- A lens that is closer to the retina, making the image brighter
- The tapetum lucidum, which reflects light, allowing for better night vision
Can Dogs See Colour?
Dogs have dichromatic vision. That is, they can only see 2 colours, shades of blue and yellow, although they can also see shades of grey. Colours such as red, orange, and green are out of a dog’s colour spectrum, so they are not visible to dogs. People have what’s called trichromatic vision, which means we can see a lot more colours than dogs.
Do Dogs Have Side Vision?
A dog’s eyes are spaced slightly farther apart than ours, at a 20-degree angle. This greater angle increases the field of view and therefore a dog’s peripheral (side) vision.
How Do You Check a Dog’s Vision?
Checking a dog’s vision is very basic. If a dog can walk into a room through the door or navigate an obstacle course in an exam room in bright and dim light, they are said to have decent vision. Dog eye specialists, or veterinary ophthalmologists, can perform dog eye exams, check their vision, and perform surgery to help dogs see better, such as cataract surgery.