When we examine an object, the rays reflected from it fall into both our eyes, which form two images and send information about them to the brain, where, in turn, one picture is formed from a combination of these two images. Then why do we need two eyes? Why does the brain need any extra trouble - to form one visual image from two images? Why don't we, like the Cyclops, have one eye in the middle of the forehead?
Depth of space
Two eyes give us what one eye is not able to give - stereoscopic vision. The eyes are located one from another at a distance of about six centimeters, that is, we observe objects with each eye at different angles.
Interesting fact: binocular vision helps to perceive the depth of space.
This can be verified. Set an alarm at a distance of 30 centimeters. Look at him with two eyes. Now close your right eye and look again. Then close your left eye, and it will seem to you that the alarm clock has moved slightly, and you look at it from a different position. The right eye sees the alarm a little bit to the right, the left, respectively, a little bit to the left. If these images overlap, then they will not match.
But the brain, perceiving two such images, combines them and forms a three-dimensional image of the object. When you look with two eyes, you perceive the depth of space.If you look at the alarm clock with one eye, the watch seems flat. Vision with two eyes is called binocular. Just like with binoculars, we look at the world through two lenses.
Eyes of other animal species.
The eyes of other animal species are not located in the same way as ours. At the sparrow, the eyes are on the sides of the head. Each eye has completely different non-coincident visual fields. This achieves a good overview, neither a tasty fly nor a formidable predator will escape the bird's eyes.
The eyes of birds of prey, such as eagles and vultures, look forward like human eyes. True, the eyes of these birds are arranged like telescopes, which allows them to see small objects at a great distance. Adult insects have complex eyes: they consist of facets, like a processed diamond of faces. Each facet is a lens.
Each eye of a housefly consists of 4,000 facets. When a fly looks at a flower, each facet sees a tiny part of it. Then the fly’s brain combines these small images into a picture of a whole flower, just as an artist combines pieces of smalt into a mosaic panel.
Such complex eyes most clearly distinguish objects from very close range. If you bring the alarm close to your eyes, the image will blur. But if you were a fly, then you would get the clearest image, crawling on the dial. Insects are very small animals, and what matters most to them is what happens at a distance of a few centimeters from them.
https://www.youtube.com/watch?v=uipQRt2lz2w
