Almost all breeds are myopic, or nearsighted, and tend to become increasingly short-sighted as they age.
The eyesight of the average dog has been compared to that of a short sighted person who has lost his glasses.
The range of vision of small and medium breeds is also limited by the fact that they are so close to the ground.
Peripheral vision varies according to the breed, depending on the way the dog's eyes are set in his skull.
The eyes of a collie or greyhound have a better field of vision than a terrier, as the terrier has close set eyes, while the collie or greyhound's eye's are placed more to the sides of the head.
Most dogs, however, possess as great a scope of vision as our own of some 180 degrees.
On the other hand, their binocular vision, (the area they see with both eyes at the same time), isn't as good as ours.
Scientists maintain that dogs, like all four-footed mammals, are color blind.
They see only different degrees of color intensity as different shades of gray.
At the same time, the dogs eye is extremely keen to detect movement, aiding in its instinctive hunting and survival ability.
The dogs night vision is also better than ours, since he can dilate his pupil more in the dark for greater light gathering.
Animals whose eyes shine in the dark possess the best night vision.
The fovea, or focusing element of the eye is not as advanced as ours which limits their ability to see as clearly as we do, giving a poor sense of depth, distance, and detail.
However, this weakness does vary by breed, age, and lifestyle.
Animals who have to hunt or search for food for survival will have a more developed eye sight than one who is cared for.
This holds true for most all the five senses of sight, smell, hearing, taste, and touch.
If you don't use it you lose it theorem, another good reason to play and exercise with your dog.
The dogs limits to his or her vision only tends to heighten their other senses of smell, taste, etc.
, and makes them more aware of their surroundings.
They tend to be more appreciative of life, food, water, and are less distracted by inanimate objects than we are.
Their reaction to reflected images in mirrors and television screens is unlike ours.
They generally investigate by sniffing, discover that the image isn't real, and lose all interest, in short, they are not fascinated by their own image.
Maybe we should try to learn a lesson from him.