How dogs see, according to a veterinary ophthalmologist
With their incredible ability to sniff out treats in a cupboard or hear a hissing sound from over a mile away, most pet owners are well aware of the fantastic senses of smell and hearing of their dogs. But when it comes to vision, people have the upper hand, at least sometimes. Jaycie Reisberg, DVM, DACVO, veterinary ophthalmologist at MedVet Salt Lake Citytalk to Yahoo! on how dogs see.
Dog eyes are different
Dog and human eyes are structured the same way, with components such as the sclera, cornea, conjunctiva, iris, pupil, lens, and retina. But dog peepers also contain elements that human eyes lack, including a third eyelid and the tapetum lucidum, which reflects light through the retina.
Reisberg explained that both species also have light-sensitive cells called cones and rods in the back of the eye. Cones and rods help the eye to decipher colors and size, shape and brightness respectively. People have more cones, while dogs have more rods.
How dogs’ vision compares to people’s
According to Reisberg, people’s vision is much better than that of dogs.
“If you hold your hand close to your dog’s face, it will be a little blurry,” he told the publication. “And they don’t see as clearly as we do for distance either. Instead of 20/20 vision, dogs have an equivalent range of 20/40 to 20/50.
In other words, if you can clearly see an object 20 feet away, your dog will see it as if it were 40 or 50 feet away.
That said, dogs can detect movement and see more clearly in the dark thanks to the tapetum lucidum and additional cones.
Dogs also have two types of cones in their eyes instead of three. Because of this, they see everything in a spectrum of blue and yellow, whereas most humans see shades of blue, yellow, red, and green.
Reisberg said some dog breeds, like Labrador Retrievers, can be nearsighted or farsighted, though it’s unlikely to affect them like humans.
However, age and associated eye conditions, such as glaucoma or cataracts, can significantly impair a dog’s vision. Feed your pet a healthy diet with Vitamin A and omega-3 fatty acids can help maintain healthy vision. Taking them for routine vet checkups is just as essential, as these visits provide an opportunity to spot and fix problems early.