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Dog vision: what and how our pets see

Almost everyone thinks that the sense of smell is more important to dogs than their eyesight. This is not entirely true.

There is a saying that dogs understand everything, they just can’t tell. A person who has seen a dog’s eyes at least once will certainly not dare to deny it. But what does a dog really feel, how does it see the world around it and people?

Many people refer to old data and say that a dog sees everything only in black and white. But this is not true. According to recent studies in the USA, dogs see colours, but they are different from the colours seen by humans. Why? The retina of a dog’s eye has fewer cones than a human eye. There are 3 types of cones in the human eye, each of which responds individually to a different colour range.

Some respond to long-wave light: red and orange, others to medium-wave light: yellow and green, and others to blue, cyan and violet. In contrast, the canine retina does not contain cones that are sensitive to the colour red. Dogs’ vision is therefore similar to people with Daltonism.

So, where a human sees blue-green, a dog will see white. But dogs have the advantage of being better at distinguishing all shades of grey than humans. This is because the retina of a dog’s eye has more rods, the light-sensitive cells responsible for the quality of vision in twilight.

Thanks to this advantage, a dog can see 3 to 4 times better in the dark than a human. So, who sees better in the dark, the dog or the human? The structures of the human and dog eye are VERY different. the human eye has a “yellow spot” in the centre of the retina where the cones are concentrated.

Undistorted light rays pass through the cornea and the lens and go straight to it. Dogs do not have this spot, so their vision is 3 times weaker than in humans. Therefore, if a dog’s eyesight was checked by an ophthalmologist, the dog would only see the third row from the top in the table, while a human would see the tenth row.

Just don’t think that dogs are short-sighted. In fact, as with all predatorsims, dogs do not need good eyesight. It is more important to have the same vision at all times of the day and to be able to distinguish the object of the hunt. Therefore, dogs can see a moving object better than a stationary one. So, it is better not to run away from the dog, as it will hold on to the prey.

Dogs can also detect distance more accurately. This may be because the sticks are close to the optical axis of the eye, where humans have a “yellow spot”. At close range, a dog’s vision is blurred and it needs a distance of 30-35 cm, whereas a human can focus its gaze a few centimetres away.

The field of vision of dogs is also different from that of humans. The field of vision of the human eye is circular, while that of the dog is ‘stretched’ sideways. The optical axes of the human eye are parallel, whereas the dog’s eye is rotated sideways by 20 degrees.

Therefore, the field of vision of dogs is 240 – 250 degrees, while that of humans is 60 – 70 degrees smaller. However, these figures can vary depending on the shape of the dog’s skull and the position of the eyes. For example, wide-eyed and short-nosed dogs have a low angle of deviation of the eyes, which results in a small field of vision

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