Dogs, our loyal companions, have a very different perspective on the world than we do as humans. Understanding dog perception is essential not only to interact more effectively with them, but also to ensure their health and happiness. This article takes a detailed look at dog visual perception, comparing it to human vision, and analyzing how this variation impacts their everyday behavior.
It is essential to understand the importance of understanding the dog’s point of view.
Perception of the environment, interaction with their owner, and response to stimuli are affected differently in dogs due to fundamental differences between canine and human vision. By taking these differences into account, dog owners can improve their communication with their pets and adjust their environment to meet their companions’ visual needs.
Comparing with human perception
Although humans and dogs have similarities in eye structure, their differences are striking. For example, humans have trichromatic vision that allows them to perceive a wide range of colors, while dogs have dichromatic vision with the limited ability to distinguish certain colors. Dogs navigate the world differently because of these differences, which has important implications.
1. Structure of the dog’s eye
The dog, like humans, has an eye composed of various structures crucial for visual perception.
- Sclera: The eyeball is protected by a rigid outer layer that gives it its shape.
- Cornea: It is transparent and serves to cover the front of the eye, helping to focus the light that enters it.
- Iris: The iris, which is the colored part of the eye, provides light regulation by adjusting the diameter of the pupil to control its entry.
- Ciliary body: It adjusts the shape of the lens in order to focus objects at different distances.
- Choroid: Blood vessels lie between the sclera and the retina to provide nutrition to the eye.
- Retina: It is in the retina, which is the inner layer, that the image takes shape. Cones and rods are present in its structure, thus allowing light to be captured.
Visual perception is influenced by cones and rods.
There are two types of photoreceptors in the retina: cones and rods.
- Cones: These cells, in bright light, enhance color perception. Dogs’ limited color perception is because they have fewer cones than humans.
- Rods: The cells are essential for night vision because they respond more intensely to low light levels. Dogs, having a higher density of rods than humans, benefit from sharper vision in the dark.
2. Vision attributes in dogs
Visual acuity
Dogs’ ability to discern detail is influenced by the difference in visual acuity from humans.
Vision disorders such as myopia and presbyopia in dogs.
In general, dogs have poorer visual acuity than humans. It is common for them to suffer from myopia, which means they see objects closer than far away. As they age, they can also develop presbyopia, which makes it difficult to focus on nearby objects.
Problem seeing at all distances.
According to one estimate, dogs have a vision of about 20/75, which is lower than that of humans, who are generally considered to have 20/20. This implies that for a dog to see as clearly as a human at 75 meters, they would have to approach the object from 20 meters away.
Color perception
Bichromatic vision (blue and yellow)
Dogs primarily see the world in variations of blue and yellow. The cones in their retinas are sensitive to blue and yellow colors, but not to red. This means that red, orange, and green are not perceived by them in the same way as we are.
Difficulty differentiating between the colors red, orange and green.
It is likely that to a dog, these colors are perceived as variations of gray or brown. Limited color perception impacts how they perceive certain objects such as toys or road signs.
Impact of brightness on the way we perceive colors
Light can also affect color perception in dogs. Although their night vision remains better than that of humans thanks to the high density of their rods, cats see colors even less well in low light.
Field of vision
Enhanced peripheral vision (between 250 and 280 degrees)
Depending on the breed, dogs have a much wider field of vision than humans, ranging from 250° to 280°. The lateral position of the eyes on the head allows for a wide field of vision, allowing you to see more of your surroundings without having to turn your head.
Compared to the human field of vision which is 180°…
In comparison, humans have a limited field of vision of about 180°, while dogs can detect movements or objects that are in their peripheral area not accessible to human eyes. This ability is a valuable resource for hunting and surveillance.
3. Night vision
Thanks to the tapetum lucidum, the animal is able to see in the dark.
Thanks to a structure called the tapetum lucidum located behind the retina, dogs have excellent vision in low light conditions. Thanks to this reflective layer, dogs are able to see better in the dark because it amplifies the available light.
Dogs’ ancestors had night vision, which played a crucial role in their evolution.
Dogs’ ability to see in the dark is a legacy of their past evolution. Night vision was a crucial skill for dogs’ ancestors as they were predators seeking to capture their prey at night. This advantage remains valuable today, especially for breeds that need to work or hunt at night.
4. Perception of movement
Increased frequency vision allows movement to be detected quickly.
Due to their higher frequency of vision, dogs are highly sensitive to movement. Even from a distance, they are able to spot movements that humans might miss. This is why dogs often react instantly to any movement, whether it is a toy being thrown or a person approaching.
It is difficult to distinguish stationary objects.
However, this sensitivity to motion has a downside: Dogs have difficulty perceiving objects that are not moving. A stationary object can go unnoticed, especially if it is far away. This is why dogs can sometimes seem to ignore an object that is directly in front of their eyes until it moves.
5. Comparison of human vision
The advantages and disadvantages of dog vision compared to human vision.
Dogs’ vision has both advantages and disadvantages compared to humans. Their ability to see in the dark and their wide field of vision clearly puts them at an advantage when it comes to hunting or scouting. However, their less sharp vision and limited ability to distinguish colors can make some tasks more difficult.
Concrete examples (like catching a ball, spotting a movement)
For example, when a dog catches a ball in motion, his ability to detect motion gives him an advantage. However, if the goal is to spot a red ball that is stationary on a green field, he may have difficulty distinguishing it because the colors are the same for him.
6. The most common eye diseases in dogs
Glaucoma
Glaucoma causes increased pressure inside the eye, which can cause pain and eventually lead to vision loss. It is urgent to consult a veterinarian in order to preserve the dog’s vision.
Cataract
If cataracts are left untreated, they can also lead to complete loss of vision. Many older dogs are affected by this condition, which can be resolved with surgery.
Uveitis
Uveitis, an inflammation of the middle layer of the eye, can cause eye pain, photophobia, and visual changes. Treatment may involve the use of anti-inflammatory drugs and, in some cases, surgery.
Cherry-eye
Cherry eye refers to the enlargement of the nictitating gland (the third eyelid), which appears as a red mass in the corner of the eye. Even if it is benign, surgery may be necessary to prevent possible complications.
Lens dislocation
Blindness or vision problems can be caused by the lens moving out of its normal position, also known as lens luxation.
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Conclusion
Dogs’ vision is a marvel of nature, perfectly adapted to the unique needs they have. In this text, we have taken an in-depth look at how dogs perceive their environment, from their sharp vision to their ability to see in the dark, as well as their ability to distinguish colors and detect motion.
