How can dogs see dogs can distinguish shades of blue, indigo and purple, but there is no special perception of high-colored colors such as red and green in the spectrum. Red is dark to dogs, while green is white to dogs, so a green lawn looks like a white lawn to dogs. Compared to humans, dogs have only about three-quarters of the vision of humans. Among all animal species, the dog’s eyesight is about medium. But dogs have a special ability to detect moving objects; dogs can detect a picture that moves 70 lines per second, while the average television picture moves about 60 lines per second. Dogs also have better vision than people when the light is dim. Dogs are natural carnivores and survive by hunting, so they have considerable eyesight in the dark. Dogs’ eyes can see short wavelengths of color, so at sunrise or sunset, dogs can see more clearly than people. But in the darkness for all no light, dogs can not see. In addition, the dog’s cornea is also larger, allowing more light to enter the eye, so it is easier to see things in the dim light. Dog vision and breed-related short-nosed breeds (such as bulldogs) can see a longer depth of field, while long-nosed breeds (such as shepherds) have a wider field of view. In addition the cranial shape of the dog and the length of the nose can also affect its vision. It is generally accepted that most dogs are slightly nearsighted. A few have hyperopia; however, neither myopia nor hyperopia is high.
