How nearsighted people see. How myopic people see: what happens to vision

A nearsighted person sees poorly without glasses; but what, in fact, he sees and exactly how objects appear to him - people with normal vision have a very vague idea about this. Meanwhile, there are quite a lot of myopic people, and it is useful to get acquainted with how they picture the world around them.

First of all, a nearsighted person (of course, without glasses) never sees sharp contours: all objects for him have blurry outlines. A person with normal vision, looking at a tree, distinguishes individual leaves and twigs that stand out clearly against the sky. The nearsighted one sees only the formless green mass unclear, fantastic outlines; small parts disappear for him.

To myopic people, human faces generally appear younger and more attractive than to a person with normal vision; wrinkles and other minor facial imperfections are not noticed by them; rough red skin color (natural or artificial) seems to them softly ruddy. We are surprised at the naivety of some of our acquaintances, who are mistaken by almost 20 years in determining the age of people, we are amazed at their strange taste in assessing beauty, we blame them for discourtesy when they look us straight in the face and seem not to want to find out... All this often happens simply from myopia.

“At the Lyceum,” recalls the poet Delvig, a contemporary and friend of Pushkin, “I was forbidden to wear glasses, but all the women seemed beautiful to me; How disappointed I was after graduation!” When a nearsighted person (without glasses) talks to you, he does not see your face at all - in any case, he does not see what you expect: there is a vague image in front of him, and it is not surprising that, meeting you again an hour later, he no longer sees you. recognizes you. For the most part, a myopic person recognizes people not so much by their appearance as by the sound of their voice: the lack of vision is compensated by the sophistication of hearing.

It is also interesting to observe how the world appears to myopic people at night. When illuminated at night, all bright objects - lanterns, lamps, illuminated windows, etc. - grow for a myopic person to huge size, turning the picture into a chaos of shapeless bright spots, dark and foggy silhouettes. Instead of lines of lanterns on the street, myopic people see two or three huge bright spots, which obscure the rest of the street for them. They do not distinguish the approaching car; instead, they see only two bright halos (headlights), and behind them a dark mass.

Even the night sky has a different appearance for the nearsighted than for the normal eye. A nearsighted person sees only stars of the first three or four magnitudes; therefore, instead of several thousand stars, only a few hundred are available to him. But these few stars seem to him large lumps Sveta. The moon appears huge and very close to a myopic person; the crescent moon takes on an intricate, fantastic shape for him.

The reason for all these distortions and the apparent increase in the size of objects lies, of course, in the structure of the myopic eye. Myopic eye too deep - so much so that the refraction of its parts collects the rays of external objects not on the retina itself, but somewhat in front of it. The retina, which covers the fundus of the eye, is reached by bundles of diverging rays, which give blurry, blurry images.

A nearsighted person sees poorly without glasses; but what, in fact, he sees and exactly how objects appear to him - people with normal vision have a very vague idea about this. Meanwhile, there are quite a lot of myopic people, and it is useful to get acquainted with how they picture the world around them.

First of all, a nearsighted person (of course, without glasses) never sees sharp contours: all objects for him have blurry outlines. A person with normal vision, looking at a tree, distinguishes individual leaves and twigs that stand out clearly against the sky. The myopic person sees only a shapeless green mass of unclear, fantastic outlines; small details disappear for him.

To myopic people, human faces generally appear younger and more attractive than to a person with normal vision; wrinkles and other minor facial imperfections are not noticed by them; rough red skin color (natural or artificial) seems to them softly ruddy. We are surprised at the naivety of some of our acquaintances, who are mistaken by almost 20 years in determining the age of people, we are amazed at their strange taste in assessing beauty, we see them in discourtesy when they look us straight in the face and seem to not want to find out...

All this often occurs simply from myopia.

“At the Lyceum,” recalls the poet Delvig, a contemporary and friend of Pushkin, “I was forbidden to wear glasses, but all the women seemed beautiful to me; I was so disappointed after graduation!” When a nearsighted person (without glasses) talks to you, he does not see your face at all - in any case, he does not see what you expect: there is a vague image in front of him, and it is not surprising that, meeting you again an hour later, he no longer sees you. recognizes you. For the most part, a myopic person recognizes people not so much by their appearance as by the sound of their voice: what they lack in vision is made up for by the sophistication of their hearing.

It is also interesting to observe how the world appears to myopic people at night. When illuminated at night, all bright objects - lanterns, lamps, illuminated windows, etc. - grow to enormous sizes for the nearsighted, turning the picture into a chaos of shapeless bright spots, dark and foggy silhouettes. Instead of lines of lamps on the street, myopic people see two or three huge bright spots that obscure the rest of the street for them. They do not distinguish the approaching car; instead, they see only two bright halos (headlights), and behind them a dark mass.

Even the night sky has a different appearance for the nearsighted than for the normal eye. A nearsighted person sees only stars of the first three or four magnitudes; therefore, instead of several thousand stars, only a few hundred are available to him. But these few stars seem to him like large lumps of light. The moon appears huge and very close to a myopic person; the crescent moon takes on an intricate, fantastic shape for him.

The reason for all these distortions and the apparent increase in the size of objects lies, of course, in the structure of the myopic eye. The myopic eye is too deep - so much so that refracted rays from external objects are collected not on the retina itself, but somewhat in front of it. The retina, which covers the fundus of the eye, is reached by bundles of diverging rays, which give blurry, blurry images.

CHAPTER TEN

SOUND AND HEARING

How to find an echo?

No one saw him, but everyone heard him. Without a body, but it lives, Without a tongue, it screams.

Nekrasov

Among the stories of the American humorist Mark Twain there is a funny fiction about the misadventures of a collector who had the idea of ​​making a collection for himself... what would you think? Echo! The eccentric tirelessly bought up all those plots of land where multiple or otherwise remarkable echoes were reproduced.

“First of all, he bought an echo in Georgia, which was repeated four times, then six times in Maryland, then 13 times in Maine. The next purchase was a 9x echo in Kansas, followed by a 12x echo in Tennessee, purchased cheaply because it needed repairs: part of the cliff had collapsed. He thought that it could be repaired by completion; but the architect who took on this task had never built an echo and therefore completely ruined it - after processing it could only be suitable for sheltering the deaf and dumb..."

This is, of course, a joke; however, remarkable multiple echoes exist in various, mainly mountainous, areas globe, and some have long gained worldwide fame.

Let's list a few famous echoes. At Woodstock Castle in England, the echo clearly repeats 17 syllables. The ruins of Derenburg Castle near Halberstadt produced a 27-syllable echo, which, however, fell silent since one wall was blown up. The rocks, spread out in the shape of a circle near Adersbach in Czechoslovakia, repeat, in a certain place, three times 7 syllables; but a few steps from this point even the sound of a shot does not give any echo. Quite multiple echoes were observed in one (now defunct) castle near Milan: a shot fired from an outbuilding window was echoed 40–50 times, and a loud word 30 times.

It is not so easy to find a place where the echo is clearly audible even once. In Russia, however, it is relatively easy to find such places. There are many plains surrounded by forests, many clearings in the forests; It’s worth shouting loudly in such a clearing that a more or less distinct echo can be heard from the forest wall.

In the mountains, echoes are more varied than on the plains, but they are much less common. Hear the echo in mountainous area more difficult than on a forest-fringed plain.

Rice. 148. There is no echo.

You will now understand why this happens. Echo is nothing more than the return of sound waves reflected from some obstacle; as with the reflection of light, the angle of incidence of the “sound beam” is equal to the angle of its reflection. (The sound beam is the direction in which they run sound waves.)

Now imagine that you are at the foot of the mountain (Fig. 148), and the obstacle that should reflect the sound is located above you, for example in AB. It is easy to see that sound waves propagating along the lines Ca, Cb, Cc, when reflected, will not reach your ear, but will be scattered in space in the directions aa, bb, cc. It’s another matter if you place yourself at the level of the obstacle or even slightly above it (Fig. 149). Sound coming down in the directions Ca, Cb will return to you along the broken lines CaaC or CbbbC, reflecting off the ground once or twice. The deepening of the soil between both points further contributes to the clarity of the echo, acting like a concave mirror. On the contrary, if the ground between points C and B is convex, the echo will be weak and will not even reach at all.

your ear: such a surface scatters sound rays like a convex mirror. Finding an echo on uneven terrain requires some skill. Even

Having found a favorable place, you must also be able to evoke an echo. First of all, you should not place yourself too close to the obstacle: the sound must travel a long enough path, otherwise the echo will return too early and merge with itself.

Rice. 149. Distinct echo.

sound. Knowing that sound travels about 340 m per second, it is easy to understand that if we were placed at a distance of 85 m from the obstacle, we should hear an echo half a second after the sound.

Although the echo generates “a response in the empty air to every sound,” it does not respond equally clearly to all sounds. The echo is not the same, “whether a beast roars in a deep forest, a horn blows, thunder roars, or a maiden sings behind a hill.” The sharper and more abrupt the sound, the clearer the echo. The best way to create an echo is by clapping your hands. Sound human voice less suitable for this, especially the voice of a man; high tones of women's and children's voices give a clearer echo.

Sound instead of a measuring tape

Knowing the speed of sound in air can sometimes be used to measure the distance to an inaccessible object. Such a case is described by Jules Verne in his novel “Journey to the Center of the Earth.” During underground wanderings, two travelers - a professor and his nephew - lost each other. When they finally managed to exchange voices from afar, the following conversation took place between them:

"- Uncle! - I shouted (the nephew tells the story. - Ya. P.).

– What, my child? – I heard after some time.

– First of all, how far are we from each other?

– It's not hard to find out.

– Is your chronometer intact?

- Yes.

– Take it in your hands. Say my name and notice exactly the second you start speaking. I will repeat the name as soon as the sound reaches me, and you will also notice the moment when my answer reaches you.

– Fine. Then half the time elapsed between the signals and the response will show how many seconds the sound takes to reach you. Are you ready?

- Yes.

– Attention! I say your name.

I put my ear to the wall. As soon as the word “Axel” (the name of the narrator - Ya.P.) reached my ears, I immediately repeated it and began to wait.

“Forty seconds,” said the uncle, “therefore, the sound reached me in 20 seconds.” And since sound travels one-third of a kilometer per second, this corresponds to a distance of almost seven kilometers.”

If you understand well what is told in this passage, it will be easy for you to solve the following problem on your own: I heard the whistle of a distant locomotive one and a half seconds after I noticed the white smoke that caused this sound; at what distance am I

was it from the locomotive?

Sound mirrors

A forest wall, a high fence, a building, a mountain - in general, any obstacle that reflects an echo is nothing more than a mirror for sound; it reflects sound the same way a plane mirror reflects light.

Sound mirrors are not only flat, but also curved. A concave sound mirror acts as a reflector: it concentrates “sound rays” at its focus.

Two deep plates make it possible

Rice. 150. Concave sound mirrors. perform a curious experiment of this kind. Place one plate on the table and several

Place your pocket watch a few centimeters from its bottom. Hold the other plate near your head, near your ear, as shown in Fig. 150. If the position of the watch, ear and plates is found correctly (this is possible after a series of tests), you will hear the ticking of the clock, as if coming from the plate that you are holding at your head. Illusion

How does a nearsighted person see? What's going on with his eyes? You will find answers to these and other questions in the article. Myopia is dangerous visual disorder, which people knew about as early as the fourth century BC. Aristotle himself called this anomaly “myopia,” which translated from Greek means “squinting.” How a myopic person sees is described in the article.

Myopia

Few people know how a nearsighted person sees. When myopia occurs, the individual begins to have difficulty distinguishing between various objects placed further than at a distance arm's length. According to medical statistics, myopia is a particularly common disease among patients over 10 years of age. The number of such people is growing every year.

As a rule, myopia begins to progress from 7 to 13 years of age and can remain at the last level or develop further, worsening a person’s vision more and more every year.

Causes

You don't know how myopic people do they see? The photo presented in the article demonstrates their abilities visual system.

Myopia occurs due to the following reasons:

• Hereditary predisposition.
• Active period growth, causing a sharp stretching of the fundus muscles.
• Head injuries received during childbirth.
• Excessive load At school.
• Spending long periods of time in front of the TV, computer, tablet, smartphone.
• Long periods of reading books without good lighting.

What's happening to the eyes?

Many people ask the question: “How does a nearsighted person see?” It is known that a healthy individual with 100% vision is very rare. After all, in view various factors Almost all people have slightly impaired vision.

How healthy man sees objects? The rays reflected from them pass through the optical structure of the eye and focus the image on the retina. With myopia, the rays are focused in front of the retina, so the image reaches it in a blurred form. This only happens when a person with visual impairment looks into the distance. As a result, it allows parallel rays of light to hit the retina.

It is important to know that the rays emanating from objects placed close are not parallel, but slightly diverge from each other. This nuance allows a nearsighted person to see them better. After all, after refraction, the image appears precisely on the retina of the eye. Now you know why people with myopia have poor distance vision and good near vision.

Distorted image

Usually the distorted image does not reach the retina or appears on it in an unnatural form due to:

• Disorders of the optical structure of the eye, which leads to excessive refraction of rays.
• Shape transformations eyeball(with myopia, the muscles of the fundus of the eye relax, causing the eye to become longer).

It should be noted that sometimes one individual has both versions of the visual disorder.

What do they see?

So how do nearsighted people see the world? This question is not easy to answer. Imagine that you cannot concentrate on an object and see it blurry, noticing only its outlines. A similar effect can be compared to setting the camera on a smartphone. After all, at this moment, at first the picture turns out to be soapy or cloudy. Also, when watching a film, the character in the foreground is clearly visible, and the background blurs, and the viewer can only discern the silhouettes of objects located behind the character.

This is exactly how myopic people see the world around them without the use of glasses. Well, if the patient puts on glasses prescribed by his doctor, he will improve his vision and be able to see everything around him in its natural form.

This effect is achieved using optical lenses placed in the frame. They transmit light rays through themselves into correct form. As a result, the resulting image appears directly on the retina.

Besides, optical lenses cause the eye muscles to tense, which is why the patient begins to see better. Don't want to suffer from vision loss? Observe basic rules preserve it and contact your ophthalmologist in time.

Vision minus 2

Let's find out how a myopic person sees at minus 2. In reality, people with this degree of myopia do not experience significant discomfort. A person can easily see objects placed 1.5 m away from him. He can also easily distinguish the contours of objects located a little further away. With the indicated acuity, the degree of myopia is considered weak.

A person can write and read, work at a computer, and navigate in space without using glasses. True, such myopia is accompanied by blurriness of objects placed at a distance, a feeling of tension eye muscles, headaches.

If you experience these symptoms, immediately visit an ophthalmologist. An experienced doctor will examine you, ruling out the development of various parallel pathological processes.

A decrease in vision to minus two occurs for the following reasons:

• weakness of scleral tissue;
• genetic predisposition;
• eye-strain;
• mechanical eye damage;
• weakness of accommodation;
• violation of visual hygiene.

Myopia is often caused by a lack of vitamins or pathologies of the vascular system.

Today, vision minus 2 is increasingly common among adolescents. This is caused by spending a long time on the PC. Very often in such cases deceitful myopia develops. To recreate visual function It is enough to perform specific exercises and observe a rest regime.

Vision minus 3

How does a myopic person see at minus 3? Such vision is usually diagnosed mild myopia. This violation is caused by the creation of a picture by the visual optical system not on the retina, but in front of it (as we discussed above). Therefore, any distant objects appear blurry to a person.

Doctors say that the more advanced the form of myopia, the worse the visibility. This can happen due to a number of reasons. Typically, minus 3 vision occurs due to muscle weakening. Today, experts distinguish several degrees of myopia:

1. Weak - down to minus three.
2. Average - up to minus six.
3. High - reaches minus 20.

In the first case, the membranes of the eyeball are stretched and thinned. This process negatively affects the vessels that feed the corresponding structures. Microcirculation inside the organ is disrupted.

It should be understood that vision minus three is not a death sentence. Today, ophthalmologists use laser, optical, medicinal types therapy or hardware functional healing, which allows you to successfully get rid of myopia. This well-known ophthalmological abnormality can occur at any age. It is important to go to the clinic in time and start treatment.

Vision minus 5

How does a myopic person see at minus 5? Let us remember that this is an average degree of myopia. At minus five, a person sees everything that is located at a distance of ten meters from him, as if in a fog, unclearly. He weakly sees the size and color of objects and detects that they are moving.

Often an individual with such vision does not recognize acquaintances at a distance because he cannot see their facial features. Recognition occurs, rather, by voice. This is why people with visual impairments usually have worse hearing. It should be noted that two people who have an identical visual diagnosis (for example, myopia -5) may not see the same way. One more clearly captures the shape and size of an object at a distance, the other - shades of color.

The answer to the question “How does a myopic person see at minus 4?” in this case is identical. After all, this indicator also applies to medium degree myopia.

To correct an ophthalmic disorder, diverging lenses or glasses are needed. Such devices transfer images of objects directly to the retina, as it should be with

By the way, at a short distance (30 cm from the eyes), myopic people can embroider, read, and knit without glasses. But here it is important to avoid prolonged muscle strain.

How do nearsighted people see? An ophthalmologist will tell you about this. Myopia is a common eye disease, and it is getting younger every year. This disease affects both adults and children. Not everyone understands what it means for a person to have bad vision. Not everyone can imagine how nearsighted people see objects around them. What is the world like through the eyes of myopic people? The answer to this question can be found in this material.

First, a little about this disease. The term myopia refers to a vision defect or a malfunction of the eye of a pathological nature, in which the image is not on the retina, but in front of it.

In people suffering from myopia, it occurs (axial type of myopia) or the cornea has a greater refractive power, which leads to the formation of a small focal length (refractive type). It would be better to say that a myopic person sees objects close up well, but poorly sees distant objects.

The reasons for the development of the disease can be varied, the most common of them are the following:

• heredity;
• excessive strain on the eyes: reading in a moving vehicle or in a poorly lit room, long work at the computer or close to the TV;
• weakening and overstrain of the eye muscles;
• birth and brain injuries.

The essence of visual impairment. With myopia, the image is processed not in the retina itself, but in front of it. Therefore, objects located in the distance that the patient sees acquire vague, blurry outlines.

The image of distant objects does not reach the retina for several reasons:

• irregularity, elongation of the shape of the eyeball;
• The optical system of the eye is prone to intense refraction of rays.

How do people with myopia see the world?

A myopic person sees worse without glasses, but what he sees and how the objects in question appear to him is difficult to imagine for people with normal vision. However, there are quite a lot of people suffering from myopia in the world. An interesting question is how do they see the world around them?

A peculiarity of the vision of myopic people is that a person suffering from this disease does not clearly see sharp contours: all objects appear blurry to him. A person with 100% vision, glancing at a tree, will be able to see down to individual leaves and twigs.

For him, a contour image of an object against the sky appears clearly. A nearsighted person sees a tree as a shapeless green mass with unclear, fantastic contours: small details are not visible with myopia.

Exists interesting feature vision when a nearsighted person examines the faces of other people. A myopic person sees faces younger and more attractive than a person with normal vision. The presence of wrinkles and other defects is not visible to the nearsighted. For example, they see a reddish skin tone (natural or artificial origin) as a soft ruddy color.

The statements of friends who make mistakes when determining a person’s age with a difference of almost 20 years seem naive to us. We are amazed at their strange taste in assessing beauty. Sometimes we accuse them of discourtesy when they look straight into the face of their interlocutor and do not recognize them. The reason for this is myopia.

Not all people suffering from myopia want to wear glasses. The acquisition becomes especially traumatic of this disease V childhood: V kindergarten and school. Children suffering from this disease are afraid of being judged by their peers. They often get called names hurtful words. If a person suffering from myopia does not wear glasses, he risks not perceiving the full amount of information about the world around him. As a result, failure at school, university, etc.

When a nearsighted person communicates with an interlocutor, he cannot see the facial features of the person talking to him. He doesn’t see what you think; the image and contour of the interlocutor’s face remains blurry for him. And it will not be surprising that, walking down the street and looking into your eyes, a myopic person simply does not recognize you. In most cases, a myopic person recognizes people not so much by their appearance as by the sound of their voice: the visual defect is compensated by hearing acuity.

What do they see at night?

Night - dark time days when there is not much light. Even a person with good eyesight He doesn’t always see everything at night, so what can we say about someone who has poor vision? In bright night lighting, all objects that are a source of light not only increase in size, but also grow to gigantic sizes. They resemble a chaos of shapeless blots, dark and indistinctly visible silhouettes, that is, a person sees the image as if in a fog.

Instead of the existing lines in the outline of the street lamps, myopic people see two shapeless, rather bright spots that obscure all other street objects. They do not see the approaching car itself, but instead of a car they see 2 headlights, behind which only a dark mass is visible.

Prevention

The night sky has completely different outlines for a nearsighted person. He can only see the stars large sizes in the form of a dot image. Instead of a thousand stars, myopic people see only a few hundred. Clearly visible stars appear as large clumps of flux light beam. A nearsighted person sees the moon as large and closely located; he sees the crescent moon from a fantastic, intricate perspective.

The reason for such visual illusions and the increasing size of objects is hidden in the special structure of the myopic eye. The myopic eye is so deep that the refraction of light in its parts collects the rays of external objects not in the area of ​​the retina itself, but slightly in front of it. Only beams of rays reach the area of ​​the retina covering the bottom of the eye, which diverge and ultimately transform into blurry and blurry images.

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