The Anatomy of a Dog’s Eye
The retina, the light-sensitive layer in the back of the eye, contains photoreceptors called rods and cones. During low-light situations, cones provide color vision and clear eyesight, while rods, the more prevalent photoreceptor in a dog’s eye, detect movement and vision. Dogs have an advantage over humans in both motion detection and night vision. However, dogs cannot see color in the same way as humans since their retinas contain only a tenth as many cones as human retinas.
What is it like for dogs to see the world?
Dogs use all five senses to perceive their environment. To better understand their canine friends, dog owners must appreciate that dogs have a unique visual viewpoint.
Like colorblind people, dogs can differentiate two colors, blue-violet and yellow. Dogs are also capable of distinguishing between various shades of gray. Dogs cannot recognize contrasting colors, like red, orange, yellow, and green.
Color alone isn’t enough for dogs to interpret the world, and so they must rely on other senses (smell, brightness, and texture). Even though a dog’s eyes cannot differentiate between red and green stoplights, the dog is alerted to cross the road by the light’s brightness combined with vehicular movement and noise.
Canine vision heavily relies on the dog’s ability to detect movement. Preparation and timing are critical in dog behavior. Your dog picks up on subtle shifts in your body language.
Dog Breeds That Are Predisposed to Eye Diseases and Vision Problems
Blindness, vision loss, and a lifetime of eye issues are possibilities for those with certain inherited eye diseases. Following is a list of breeds known to have vision issues.
American Cocker Spaniel
In Cocker Spaniels, cataracts are the most common cause of blindness. Cataracts can cause a dog to lose some or all of its vision. A dog’s vision may be severely impaired if more than 30% of the eye lens is damaged. Cataracts can occur in many other breeds of dogs, as well. Dogs with diabetes are also more likely to get cataracts.
Labrador and Golden Retrievers
Progressive retinal atrophy, or PRA, is a hereditary predisposition in Golden Retrievers and Labrador Retrievers. Cone and rod photoreceptor degeneration are two of the most common genetic disorders. The dog’s vision gradually deteriorates until it is entirely blind.
Great Danes
Entropion is a common eye problem in Great Danes. Entropion is one that many dog owners don’t know about until their pets exhibit symptoms, and the harm to their eyes has been done. Hereditary Entropion is an eyelid condition that causes the Great Dane’s eyelids to fold inward. The eye might become inflamed, and scar tissue can grow due to the irritation. When scar tissue or ulcers form on the cornea, it can cause vision loss and necessitate invasive surgery to restore sight.
Collie
CEA, or Collie Eye Anomaly, is a disease that affects the development of a collie’s eyes. This hereditary disorder causes underdevelopment of the eye’s blood vessels, resulting in retinal detachment and blindness. Dogs with the genetic markers for CEA should not be bred because the disorder is inherited.
Siberian Husky
The husky breed is prone to several eye disorders. Recessive genes put the Siberian Husky at risk for cataracts, corneal dystrophy, and retinal atrophy. It’s easy to confuse cataracts in dogs with the less prevalent condition known as corneal dystrophy. Corneal dystrophy is a condition in which a fatty film forms on the cornea of a dog’s eye, resulting in a cloudy blue tint. Corneal dystrophy is more common in female huskies than males.
Boston Terriers
Boston Terriers are in danger of developing glaucoma and cataracts. Due to their large, protruding eyes, they are more susceptible to eye injuries, scrapes, and other ailments of the eyeballs. Cherry eye is another eye ailment that Boston Terriers are prone to, caused by a prolapsed third eyelid which can be seen in the inside corner of a dog’s eye.
Frequently Asked Questions
How sharp is a dog’s vision compared to humans?
Dogs lack human-like vision. Humans have 20/20 eyesight. Most dogs have 20/75 visual acuity, meaning they need to be 20 feet away from an object to see it as well as a person can see at 75 feet away. Labrador Retrievers, a species widely employed as human seeing-eye dogs, have stronger eyesight.
Dogs’ vision is hazy. If a dog were a person, they would require eyeglasses to view distant objects like the traffic sign. The retina of dogs has more rods than ours that react to movement and weak light. The motion sensitivity of dogs is 10-20 times that of humans. Dogs can detect subtle changes in body posture and movement, which is why using hand gestures is a common method of training dogs.
How to Test a Dog’s Vision
Checking a dog’s vision is easy because they don’t need strong eyesight (visual acuity). A dog with good eyesight can go through a door or navigate an obstacle course in an exam room in both bright and dim light. Dog eye experts, or veterinary ophthalmologists, may examine dogs’ eyes and conduct surgery, such as cataract surgery, if necessary.
