Interesting facts about human eyes. Interesting facts about human eyes (15 photos). Optical system of the human eye

It is well known that our eyes are an important organ not only for receiving information, but also for feelings. For example, only homo sapiens have the whites of their eyes! Apes, for example, have completely black eyes. Therefore, only a person can determine other people's intentions and emotions by the eyes. From the eyes of a monkey it is absolutely impossible to understand not only her feelings, but even the direction of her gaze.

In ancient Egypt, makeup was worn by both women and men. Eyelid paint was made from copper (green paint) and lead (black paint). The ancient Egyptians believed that this makeup had healing properties. Makeup was used primarily to protect from the sun's rays and only secondarily as a decoration. Today, it is not necessary to tint the eyes to hide the flaws, you can do laser blepharoplasty of the eyelids in Reform and live in peace for several more decades.

Our eye color provides information about heredity. For example, blue eyes are more common in northern regions, brown in temperate climates, and black in the equator.

In daylight or too cold, a person's eye color can change (this is called a chameleon)

Today it is believed that people with dark eyes are stubborn, hardy, but in crisis situations they are too irritable; gray-eyed - decisive; brown-eyed are closed, and blue-eyed are hardy. Green-eyed people are stable and focused.

There are approximately 1% of people on Earth who have the color of the iris of the left and right eyes is not the same.

Mechanism with a human eye - is it possible? Undoubtedly! The most interesting thing is that such a device already exists! Mitsubishi Electric has developed an electronic eye on a chip, which is already being used in some products. This eye has the same functions as the human eye.

Why do people close their eyes when they kiss? Scientists have found out! During the kiss, we lower our eyelids so as not to faint from an overabundance of feelings. During a kiss, the brain experiences sensory overload, so by closing your eyes, you subconsciously reduce the excess intensity of passions.

The eye of large whales weighs about 1 kg. At the same time, many whales do not see objects in front of their snout.

The human eye distinguishes only seven primary colors - red, orange, yellow, green, blue, indigo and violet. But besides this, the eyes of an ordinary person are able to distinguish up to a hundred thousand shades, and the eyes of a professional (for example, an artist) up to a million shades!

According to experts, any eyes are BEAUTIFUL by internal energy, health, kindness, interest in the world and people!

Record: The Brazilian can bulge his eyes by 10 mm! This man used to work at a commercial haunted ride where he would scare the patrons. However, he is now seeking worldwide recognition for his abilities. And he wants to get into the Guinness Book of Records!

The eyes are a unique organ in structure, thanks to which a person receives about 80% of information about the world around him: about the shape, color, size, movement and other parameters of objects and phenomena. But how much do we know about our most valuable sense organ, which, according to the scientist Sechenov, provides us with about a thousand different sensations per minute? Let's take a look at the 10 most amazing facts about eyes and vision.

Source: depositphotos.com

Fact 1. The average eye diameter is 2.5 cm, weight is about 8 g, and these parameters, with a difference of a fraction of a percent, are similar in all people who have reached 7 years of age. The diameter of the eye of a newborn child is 1.8 cm, weight is 3 g. Only 1/6 of the organ of vision is visible to a person. The inside of the eye is connected to the body by the optic nerve, which transports information to the brain.

Fact 2. The human eye can only perceive three parts of the spectrum - green, blue and red. The remaining distinguishable shades (there are more than 100 thousand of them) are derived from these three colors. Only 2% of women have an additional area of ​​the retina that allows them to recognize up to 100 million shades. All children are born long-sighted, color-blind, unable to perceive colors, however, in 8% of males, color blindness remains in adulthood.

Fact 3. All people are blue-eyed. The difference in shades of the iris depends on the amount of melanin concentrated in it. The highest it is in the owners of brown eyes, the lowest - in light-eyed. So, all children are born with gray-blue eyes, which after 1.5-2 years acquire their genetic color. Thanks to this, a laser color correction procedure that cleanses the iris of melanin has become widespread. It allows you to change brown eye color to blue in a minute; but it is impossible to return the previous shade.

Fact 4. About 1% of people on the planet have different eye colors - a genetic abnormality called heterochromia. This may be the result of injuries, diseases, genetic mutations and is explained by an excess of melanin in one organ of vision and its deficiency in another. With partial (sector) heterochromia, there are areas of different colors on the same iris, with absolute - the eyes are entirely of two different colors. More often than in humans, heterochromia occurs in animals - cats, dogs, horses and buffaloes. In ancient times, people with heterochromia were considered sorcerers and witches.

Fact 5. One of the rarest shades of the iris is green. This beautiful color is obtained due to the presence in the outer layer of the iris of the yellow pigment lipofuscin, combined with a blue or blue tint in the stroma. It is found in only 1.6% of the world's population and is eradicated in families with a dominant brown-eyed gene.

Fact 6. The cornea of ​​the human eye is similar in structure and structure of collagen to the shark, which is often used as a substitute for eye surgeries. Today, transplantation of the cornea of ​​a sea predator to a human (an achievement in zoo-ophthalmology) is a highly effective method of treating severe diseases of the organ and restoring vision.

Fact 7. The retina of the eye is unique: it has 256 unique characteristics (the probability of repetition in two different people is 0.002%). Therefore, iris scanning along with fingerprinting can be used for personal identification purposes. Already today, the procedure for recognizing a person by the iris of the eye is used in the customs services of the United States and Great Britain.

The organ of human vision is the eyes, with their help the brain receives the visual information we need for orientation in space and communication with the outside world.

The light flux reflected from the object penetrates through the cornea, lens and vitreous body of the eye to the retina, where the nerve impulse originates. Through the optic nerve, it enters the visual centers located in the occipital lobes of the brain.

It is there that the formation of a single image obtained simultaneously from two eyes takes place. This complex process is called binocular vision, and this is far from the only interesting fact related to our eyes and the ability to see.

Human vision: interesting facts

How many eye colors are there in the world, why are people born colorblind, and why do their eyes automatically close when they sneeze? The answers to these and other interesting questions about vision will be discussed below.

Fact #1: Size matters

The human eyeball does not have the shape of a regular ball, as is commonly believed, but a sphere slightly flattened from front to back. The weight of the eye is approximately 7 g, and the diameter of the eyeball is the same in all healthy people and is 24 mm. It may deviate from this indicator in diseases such as farsightedness.

Fact #2: eye color

All children are born with gray-blue eyes, and only after two years they acquire their true color. Human eyes come in different shades - depending on the concentration of melanin pigment in the iris of the eyeball.

The rarest eye color in humans is green. Red eyes are characteristic of albinos and are explained by the complete absence of coloring pigment and the color of blood vessels that appear through the transparent iris.

The iris of each person is individual, so its pattern can be used for identification along with fingerprints.

Fact #3: Light and Darkness

Different types of retinal photoreceptors are responsible for the ability of a person to see in the light and in the dark. Rods are more light sensitive and help us navigate in the absence of sufficient light.

Violation of their functioning causes the development of the so-called night blindness - a disease in which a person sees very poorly in twilight lighting.

Thanks to cones, a person distinguishes colors. The human eye has an average of 92 million rods and 4 million cones.

Fact #4: upside down

The image of objects projected onto the retina of the eye is inverted. This optical effect is similar to the projection of a lens in a camera. So why do we see the world around us normally, and not upside down?

This is the merit of our brain, which perceives the image and automatically brings it to its normal position. If you wear special glasses that flip the picture for a while, then at first everything will be seen upside down, and then the brain will adapt again and normalize the optical distortion.

Fact #5: Colorblindness

The disease, also called color blindness, is named after the English scientist John Dalton. He did not distinguish red color and studied this phenomenon, relying on his own sensations. Thanks to the book he published with a detailed description of the disease, the word "color blindness" came into use.

According to statistics, most men are affected by this hereditary disease, and only 1% of the number of color blind people are women.

Fact number 6: you - to me, I - to you

Despite all the achievements of modern medicine, it is impossible to make a complete eye transplant from one person to another. This is due to the close connection of the eyeball with the brain and the inability to fully restore the nerve endings - the optic nerve.

At the moment, only transplantation of the cornea, lens, sclera and other parts of the eye is possible.

Fact #7: Be healthy!

When you sneeze, your eyes automatically close. This protective reaction of our body is fixed at the level of reflexes, since with a sharp release of air through the mouth and nose, the pressure in the sinuses of the nose and the blood vessels of the eyes increases abruptly. Closed eyelids when sneezing help to avoid rupture of eye capillaries.

Fact #8: I look far

The acuity of human vision is two times lower than that of an eagle, which is associated with the peculiarity of the structure of the human eye and the ability of the lens to change its curvature.

The area on the retina with the highest concentration of photosensitive cells is called the macula lutea. And the point where both rods and cones are absent is called the "blind spot". A person cannot see with this place.

Fact number 9: diseases of the organs of vision

According to statistics from the World Health Organization, almost 300 million people in the world are familiar with the problem of visual impairment. And 39 million of them are blind!

As a rule, vision loss is caused by age, and advanced diabetes is also increasingly called among the causes.

Among the diseases of the organs of vision that can be corrected with glasses, contact lenses or surgery, the most common are farsightedness, myopia and astigmatism. In order not to miss the first signs of the disease, it is necessary to visit an ophthalmologist for preventive purposes once a year.

Fact #10: glasses and lenses

The constant wearing of properly fitted glasses and contact lenses does not harm the eyes and cannot impair a person's vision. But the benefits of sunglasses should not be overestimated. Even high-quality dark glass lenses of such glasses are not able to block all the ultraviolet rays, so it is not recommended to look directly into the sun with them.

The role of vision is difficult to overestimate. It has been proven that a person receives 90% of information through the eyes, so the difference between the concepts of “just seeing” and “seeing life 100%” becomes huge. At the same time, the organ of vision is one of the most complex in our body. So, it is controlled by very "fast" muscles - the eye can make more than 120 movements-oscillations per second, even if you just focused your eyes at one point. These and other interesting facts about vision have a big impact on our ability to see.

• Fact number 1. Size matters. The eyeball in all healthy people normally has almost the same weight of 7-8 g. Its size is also static and is 24 mm. The difference in this indicator in healthy people varies only in fractions of a millimeter. At the same time, the quality of human vision directly depends on the size of the eye. So, if it is more than normal, there is myopia, or myopia. Otherwise - .
• Fact number 2. eyesalso need freedom. The limitation of space greatly affects the development of myopia. Residents of large cities often do not have to look into the distance, since all objects are close enough. In rural areas, there are more open spaces, which means that a person trains his pupil more often, shifting his gaze from objects located in the distance to those that are directly in front of him. Therefore, parents need to pay their children's attention more to objects located far away, otherwise the child's world will narrow down to a notebook and a computer monitor lying on the table and the risk of visual impairment will increase.
• Fact number 3. We look with the eye, we see “in the mind”. The organ of vision is a "conductor" of information, and our brain analyzes it. At the same time, he always corrects the images that we perceive. Many have heard that in reality the image is projected upside down on the retina, and our brain translates it into a normal position. This is easy to verify if you put on special glasses that will turn the picture upside down. After some time, the brain will adjust, and this distortion of vision will disappear. In addition, in the eyes of every person there are so-called blind spots - areas of the retina that are insensitive to light. To find them, conduct an experiment right now. Close your right eye and look with your left eye at the circled cross. Without taking your eyes off him, try bringing your face closer to the monitor. At some point, the cross on the left will disappear. But if you looked with two eyes, the brain would "neutralize" this effect, using information coming from the other eye.

• Fact number 4. How long ago did you visit an ophthalmologist? A study* has been conducted to assess people's attitudes towards the importance of eye exams. More than 6,000 respondents from different countries took part in it. During the study, interesting facts about vision were obtained. Only 54% of the participants had at least once been examined by an ophthalmologist, the rest said that this was not necessary. 44% of respondents believe that if they see at an acceptable level for themselves, then their eyes are absolutely healthy. At the same time, 79% of respondents noted that improved vision would allow them to more effectively cope with work, play sports and, in general, improve the quality of life.
• Fact number 5. Take care of your eyes from a young age! Despite the development of science, a complete eye transplant from one person to another is impossible. This is due to the fact that the visual apparatus is closely connected with the brain, and it is impossible to restore nerve endings during such an operation. At the moment, medicine has reached the possibility of transplanting only certain parts of the eye for vision correction - the cornea, sclera, lens, etc.

It is important to know that the use of "outdated" glasses or contact lenses can cause headaches.

*Global Attitudes and Perceptions About Vision Care, The Vision Care Institute™, LLC

Our conversation today is about vision. The ability to see is the most faithful and reliable assistant of man. It allows us to navigate and interact with the world around us.

About 80% of all information a person receives through vision. Let us consider the mechanism for the emergence of a continuously changing visible picture of the environment.

How Visible Image Is Created

Each of the 6 sense organs (analyzers) of a person includes three most important links: receptors, nerve pathways, and the brain center. Analyzers belonging to different sense organs work in close "collaboration" with each other. This allows you to get a complete and accurate picture of the world around you.

The function of vision is provided by a pair of eyes.

Optical system of the human eye

The human eye has a spherical shape with a diameter of about 2.3 cm. The front part of its outer shell is transparent and is called cornea. The back part - the sclera - consists of a dense protein tissue. Directly behind the protein is the choroid, permeated with blood vessels. The color of the eyes is determined by the pigment contained in its front (iridescent) part. The iris contains a very important element of the eye - hole (pupil), transmitting light into the eye. Behind the pupil is a unique invention of nature - lens. It is a biological, completely transparent biconvex lens. Its most important property is accommodation. Those. the ability to reflexively change its refractive power when considering objects at different distances from the observer. The convexity of the lens is controlled by a special group of muscles. Behind the lens is a transparent vitreous body.

The cornea, iris, lens and vitreous form the optical system of the eye.

The coordinated work of this system changes the trajectory of light rays and directs light quanta to the retina. On it appears a reduced image of objects. On the retina are photoreceptors, which are branches of the optic nerve. The light irritation they receive is sent along the optic nerve to the brain, where the visible image of the object is formed.

However, nature has limited the visible part of the electromagnetic scale to a very small range.

Only electromagnetic waves with a length of 0.4 to 0.78 microns pass through the light-conducting system of the eye.

The retina is also sensitive to the ultraviolet part of the spectrum. But the lens does not let through aggressive ultraviolet quanta and thus protects this most delicate layer from destruction.

Yellow spot

Against the pupil on the retina is a yellow spot, on which the density of photoreceptors is especially high. Therefore, the image of objects that fall into this area is especially clear. With any movement of a person, it is necessary that the image of the object be kept in the region of the yellow spot. This happens automatically: the brain sends commands to the oculomotor muscles, which control the movement of the eyes in three planes. In this case, the movement of the eyes is always coordinated. Obeying the received commands, the muscles force the eyeballs to turn in the right direction. This ensures visual acuity.

But even when we look at a moving object, our eyes move very quickly from side to side, continuously supplying “food for thought” to the brain.

Color and twilight vision

The retina consists of two types of nerve receptors - rods and cones. Rods are responsible for night (black and white) vision, and cones allow you to see the world in all its splendor of colors. The number of rods on the retina can reach 115-120 million, the number of cones is more modest - about 7 million. The rods react even to individual photons. Therefore, even in low light, we distinguish the outlines of objects (twilight vision).

But cones can show their activity only with sufficient light. They require more energy to activate because they are less sensitive.

There are three types of light-perceiving receptors corresponding to red, blue and green.

Their combination allows a person to recognize the whole variety of colors and thousands of their shades. And their imposition gives white color. By the way, the same principle is used in.

We see the world around us because all objects reflect the light falling on them. Moreover, the wavelengths of the reflected light depend on the substance or paint applied to the object. For example, the paint on the surface of a red ball can only reflect wavelengths of 0.78 microns, while green foliage reflects a range from 0.51 to 0.55 microns.

Photons corresponding to these wavelengths, falling on the retina, can only affect the cones of the corresponding group. A red rose lit with green turns into a black flower because it is unable to reflect these waves. In this way, bodies themselves have no color. And the entire huge palette of colors and shades available to our vision is the result of an amazing property of our brain.

When a light flux corresponding to a certain color falls on a cone, an electrical impulse is formed as a result of a photochemical reaction. A combination of these signals rushes to the visual cortex, building an image there. As a result, we see not only the outlines of objects, but also their color.

Visual acuity

One of the most important properties of vision is its sharpness. That is, his the ability to perceive two closely spaced points separately. For normal vision, the angular distance corresponding to these points is 1 minute. Visual acuity depends on the structure of the eye and the correct functioning of its optical system.

Secrets of the eye

At a distance of 3-4 mm from the center of the retina there is a special area devoid of nerve receptors. For this reason, it was called the blind spot. Its dimensions are very modest - less than 2 mm. Nerve fibers from all receptors go to it. Combining in the blind spot zone, they form the optic nerve, through which electrical impulses from the retina rush to the visual zone of the cerebral cortex.

By the way, the retina has somewhat puzzled scientists - physiologists. The layer containing nerve receptors is located on its back wall. Those. light from the outside world must pass through the layer of the retina, and then “storm” the rods and cones.

If you look closely at the image that the optical system of the eye projects onto the retina, you can clearly see that it is inverted. This is how babies see him for the first two days after birth. And then the brain is trained to flip this image. And the world appears before them in its natural position.

By the way, why did nature provide us with two eyes? Both eyes project images of the same object onto the retina, slightly different from each other (since the object in question is located slightly differently for the left and right eyes). But nerve impulses from both eyes fall on the same neurons of the brain, and form a single, but volumetric image.

The eyes are extremely vulnerable. Nature took care of their safety, through auxiliary bodies. For example, eyebrows protect the eyes from drops of sweat and rain dripping from the forehead, eyelashes and eyelids protect the eyes from dust. And special lacrimal glands protect the eyes from drying out, facilitate the movement of the eyelids, disinfect the surface of the eyeball ...

So, we got acquainted with the structure of the eyes, the main stages of visual perception, revealed some of the secrets of our visual apparatus.

As with any optical device, various failures are possible here. And how a person copes with visual defects, and what properties nature has endowed with his visual apparatus - we will tell at the next meeting.

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