Sharp vision. The sharpest night vision. Prevention of decreased visual acuity in children

We continue ours. For example, the name of a student from Germany, Veronica Seider, is listed in the Guinness Book of Records, the girl has the sharpest eyesight on the planet. Veronica recognizes a person's face at a distance of 1 kilometer 600 meters, this figure is about 20 times higher than the norm. Humans also see well in the dark, but nocturnal animals such as cats will give us a hundred points ahead.

Who is the owner of the most sensitive eyes?

The human eye is one of the most amazing achievements of evolution. He is able to see small dust particles and huge mountains, near and far, in full color. Working in tandem with a powerful processor in the form of a brain, the eyes allow a person to distinguish between movement and recognize people by their faces.

One of the most impressive features of our eyes is so well developed that we don't even notice it. When we enter from bright light into a semi-dark room, the level of illumination of the environment drops sharply, but the eyes adapt to this almost instantly. As a result of evolution, we have adapted to see in poor light.

But on our planet there are living beings who see in the dark much better than humans. Try reading a newspaper in deep twilight: black letters merge with a white background into a blurry gray spot in which you can’t understand anything. But a cat in a similar situation would not experience any problems - of course, if she could read.

But even cats, despite the habit of hunting at night, see in the dark not the best. Creatures with the sharpest night vision have evolved unique visual organs that allow them to capture literally grains of light. Some of these creatures are able to see in conditions where, from the point of view of our understanding of physics, nothing can be seen in principle.

To compare night vision acuity, we will use lux - these units measure the amount of light per square meter. The human eye performs well in bright sunlight, where illumination can exceed 10,000 lux. But we can see with just one lux - about as much light there is on a dark night.

Domestic cat (Felis catus): 0.125 lux

To see, cats need eight times less light than humans. Their eyes are generally similar to ours, but their device has several features that allow it to work well in the dark.

Cat's eyes, like human ones, consist of three main components: the pupil - the hole through which light enters; lens - focusing lens; and the retina, the sensitive screen onto which the image is projected.

In humans, the pupils are round, while in cats, they have the shape of an elongated vertical ellipse. During the day, they narrow into slits, and at night they open to a maximum width. The human pupil can also change size, but not in such a wide range.

The lenses of a cat are larger than those of a human, and are able to collect more light. And behind the retina, they have a reflective layer called the tapetum lucidum, also known simply as the "mirror." Thanks to him, the eyes of cats glow in the dark: light passes through the retina and is reflected back. Thus, the light acts on the retina twice, giving the receptors an additional chance to absorb it.

The composition of the retina itself in cats is also different from ours. There are two types of photosensitive cells: cones, which distinguish colors but only work in good light; and sticks - not perceiving color, but working in the dark. Humans have a lot of cones, giving us rich full-color vision, but cats have many more rods: 25 per cone (in humans, the ratio is one to four).

There are 350 thousand rods per square millimeter of the retina in cats, and only 80-150 thousand in humans. In addition, each neuron extending from the cat's retina transmits signals from about one and a half thousand rods. A weak signal is thus amplified and turned into a detailed image.

This sharp night vision has a downside: during the daytime, cats see in much the same way as people with red-green color blindness. They can tell blue from other colors, but they can't tell the difference between red, brown, and green.

Tarsier (Tarsiidae): 0.001 lux

Tarsiers are tree-dwelling primates found in Southeast Asia. Compared to the rest of their body proportions, they seem to have the largest eyes of any mammal. The body of the tarsier, if you do not take the tail, usually reaches a length of 9-16 centimeters. The eyes, on the other hand, have a diameter of 1.5-1.8 centimeters and occupy almost the entire intracranial space.

Tarsiers feed mainly on insects. They hunt early in the morning and late in the evening, with illumination of 0.001-0.01 lux. Moving along the tops of trees, they must look out for small, well-camouflaged prey in almost complete darkness and at the same time not fall, jumping from branch to branch.

Help them in this eyes, generally similar to human. The tarsier's giant eye lets in a lot of light, and its amount is regulated by strong muscles surrounding the pupil. A large lens focuses the image on the retina, strewn with rods: the tarsier has more than 300 thousand of them per square millimeter, like a cat.

These large eyes have a drawback: tarsiers are not able to move them. As compensation, nature endowed them with necks that turn 180 degrees.

Dung beetle (Onitis sp.): 0.001-0.0001 lux

Where there is manure, there are usually dung beetles. They choose the freshest pile of manure and begin to live in it, rolling balls of manure in reserve or digging tunnels under the pile to equip themselves with a pantry. Dung beetles of the genus Onitis fly out in search of manure at different times of the day.

Their eyes are very different from human ones. The eyes of insects are faceted, they consist of many structural elements - ommatidia.

Beetles flying during the day have ommatidia enclosed in pigmented shells that absorb excess light so that the sun does not blind the insect. The same shell separates each ommatidium from its neighbors. However, in the eyes of nocturnal beetles, these pigment membranes are absent. Therefore, the light collected by many ommatidia can be transmitted to only one receptor, which significantly increases its photosensitivity.

The genus Onitis includes several different species of dung beetles. In the eyes of diurnal species there are isolating pigment membranes, the eyes of evening beetles summarize signals from ommatidia, and in nocturnal species, signals from the number of receptors twice as large as those of evening beetles are summarized. The eyes of the nocturnal Onitis aygulus, for example, are 85 times more sensitive than those of the diurnal Onitis belial.

Halictid bees Megalopta genalis: 0.00063 lux

But the rule described above does not always work. Some insects can see in very low light, despite the fact that their visual organs are clearly adapted for daylight.

Eric Warrent and Elmut Kelber of the University of Lund in Sweden found that some bees have pigmented shells in their eyes that isolate the ommatidia from each other, but they are still excellent at flying and searching for food on a dark night. In 2004, for example, two scientists demonstrated that the halictid bees Megalopta genalis were able to navigate in light 20 times less intense than starlight.

But the eyes of the Megalopta genalis bees are designed to see well in daylight, and in the course of evolution, the bees had to somewhat adapt their organs of vision. After the retina has absorbed the light, this information is transmitted to the brain via the nerves. At this stage, the signals can be summed to increase the brightness of the image.

Megalopta genalis has special neurons that connect ommatidia into groups. Thus, signals coming from all the ommatidia in the group are merged together before being sent to the brain. The image is less sharp, but much brighter.

Carpenter bee (Xylocopa tranquebarica): 0.000063 lux

Carpenter bees, found in the mountains called the Western Ghats in southern India, see even better in the dark. They can fly even on moonless nights. “They are able to fly in starlight, on cloudy nights and in strong winds,” says Hema Somanathan of the Indian Institute of Science Education and Research in Thiruvananthapuram.

Somanathan discovered that carpenter bee ommatidia have unusually large lenses, and that the eyes themselves are quite large in proportion to other parts of the body. All this helps to capture more light.

However, this is not enough to explain such excellent night vision. Perhaps the carpenter bees also have ommatidia in groups, like their counterparts Megalopta genalis.

Carpenter bees don't just fly at night. “I have seen them fly during the day when their nests are being ravaged by predators,” says Somanathan. “If you blind them with a flash of light, then they simply fall, their vision is not able to process a large amount of light. But then they come to their senses and take off again.”

Of all the fauna, carpenter bees seem to have the sharpest night vision. But in 2014, another contender for the championship title appeared.

American cockroach (Periplaneta americana): less than one photon per second

direct comparison of cockroaches with other living creatures will not work, because their visual acuity is measured differently. However, their eyes are known to be unusually sensitive.

In a series of experiments described in 2014, Matti Väkström of the Finnish University of Oulu and colleagues looked at how individual light-sensitive cells in cockroach ommatidia responded to very low light. They inserted the thinnest electrodes made of glass into these cells.

Light consists of photons - massless elementary particles. The human eye needs at least 100 photons to hit it in order to feel anything. However, the receptors in the cockroach's eyes responded to movement, even if each cell received only one photon of light every 10 seconds.

A cockroach has 16,000 to 28,000 green-sensitive receptors in each eye. According to Wekstrom, signals from hundreds or even thousands of these cells are summed up in the dark (recall that up to 1,500 visual rods can work together in a cat). The effect of this summation, according to Vekstrom, is "grand," and it seems that it has no analogues in nature.

“Cockroaches are impressive. Less than a photon per second! Kelber says. “This is the sharpest night vision.”

But bees can beat them in at least one respect: American cockroaches don't fly in the dark. "Flight control is much more difficult - the insect moves quickly, and collision with obstacles is dangerous," comments Kelber. “In that sense, carpenter bees are the most amazing. They are able to fly and forage on moonless nights and still see colors.”

And a little more interesting about acute vision.

Eyes, nose, ears - in the wild, all organs are at the service of the survival of the animal. Eyes play a crucial role in the life of any living creature, but not all animals see the same way. Visual acuity does not depend on the size or number of eyes.

So, even the most vigilant among the many-eyed spiders, the jumping spider sees the victim only at a distance of 8 centimeters, but in color. It should be noted that all insects have poor eyesight.

Animals that live underground, such as moles, are generally blind. Poor eyesight in mammals that live in water, such as beavers and otters.

Animals hunted by predators have panoramic vision. It is extremely difficult to sneak up on a nightjar bird unnoticed. Her bulging large eyes have a wide slit that curves towards the back of the head. As a result, the angle of view reaches three hundred and sixty degrees!
It is interesting, for example, that eagles have two eyelids, and insects do not have eyelids at all and sleep with their eyes open. The eagle's second eyelid is absolutely transparent, it protects the eye of a bird of prey from the wind during a swift attack.

Birds of prey have the sharpest eyesight in the animal kingdom. In addition, these birds can instantly shift the focus of vision from far distances to near objects.
Feathered predators eagles see their prey at a distance of 3 kilometers. Like all predators, they have binocular vision, when both eyes look at the same object, it is easier to calculate the distance to the prey.
But the absolute champions of vigilance in the animal kingdom are representatives of the falcon family. The most famous falcon in the world - the peregrine falcon or, as it is also called, the pilgrim - can spot game from a distance of 8 kilometers.

The peregrine falcon is not only the most vigilant, but also the fastest bird, and in general a living creature, in the world. According to experts, in a swift dive flight, it is capable of reaching speeds of over 322 km / h, or 90 m / s.

For comparison: the cheetah, the fastest animal of land mammals, runs at a speed of 110 km / h; the spiny-tailed swift, living in the Far East, is capable of flying at a speed of 170 km / h. But, it should be noted that in horizontal flight the peregrine falcon is still inferior to the swift.

Peregrine falcon (lat. Falco peregrinus) is a bird of prey from the falcon family, common on all continents except Antarctica. During the hunt, the peregrine falcon plans in the sky, having found prey, it rises above the victim and dives rapidly down almost at a right angle, inflicting fatal blows to the victim with its claws.

Such different eyes.

A series of works by Armenian photographer Suren Manvelyan ( Suren Manvelyan) “Your Beautiful Eyes” shows the pupils of the eyes of animals, birds and fish shot in macro mode. Suren was born in 1976, started photography when he was sixteen years old and became a professional photographer in 2006. His photographic interests range from macro to portraits. Now he is the chief photographer for Yerevan magazine.

Visual acuity is one of the most important characteristics of the human visual analyzer. This characteristic reflects the sensitivity of the eye, as well as its ability to determine the details on visible objects.

Visual acuity at 1.0

In this article, we tried to get acquainted in more detail with how to determine visual acuity and examined how it is measured.

Visual acuity indicators

The optimal indicator is 100% visual acuity. This is the ability to distinguish between two points remote from each other, the angular resolution of which is equal to one minute, which corresponds to 1/60 of a degree. In simple words, visual acuity is a qualitative indicator of the vigilance of human eyes, which makes it possible to measure in numbers how clearly a person sees the world around him.

Normal vision in Russia is considered equal to 1.0. Visual acuity is determined using special tables that show optotypes, letters or special icons that the person being tested should see. Many do not understand where the number 1.0 comes from. This figure is determined by a specially designed scheme, which looks like this: V=d/D. The letter V refers to visual acuity. The letter d is the distance at which the test is carried out. The letter D is the distance from which the eye with normal vision sees a certain row on the measurement chart.

Methods for the study of visual acuity

Many experts argue that it is necessary to regularly undergo studies to determine visual acuity (visometry). Timely detected indicators of a decrease in this function of the human eye allow timely selection of certain corrective measures. The traditional method for determining the vigilance of the eyes is the method of using special tables. The signs (optotypes) are arranged in a certain order in the check table. It can be letters, symbols, shapes, numbers, lines, and drawings.

Each optotid occupies a field of view of 5 minutes. Separate details of the sign are covered by a viewing angle of 1 minute. There are also universal tables with optotypes, which show open circles of various diameters. These tables were named after the author of the invention "Landolt rings".

If a person undergoes a study on this table, then he is asked to determine in which direction the gap on the ring is directed. In our country, Sivtsev or Golovin tables are most often used to check visual acuity. They use standard 7 letters: W, B, M, H, K, Y, I. In the process of research, the distance to the table is also an important factor. It is about 5 meters. Before each line is indicated the distance from which a healthy eye sees a certain character.

Dividing the distance from which a person sees a certain symbol by the tabular value of a healthy eye, we get the level of visual acuity. The healthy eye sees the first line in the table at a distance of 50 meters. The visual acuity of the eye (Visus), which sees only the first line will be equal to 0.1. With each row of the table, one tenth must be added to this value. Thus, the tenth line will correspond to visual acuity, which is equal to 1.0. The exception is the eleventh (1.5) and twelfth line (2.0).

When determining visual acuity, you also need to know about the following features:

1. Compliance with the level of illumination (700 lux).
2. First examine the right eye, and then the left.
3. The eye must be covered with a special flap. In this case, physical impact should be avoided.
4. In lines 1-3, errors in determining the sign are not allowed. From lines 4 to 6, one error is allowed. From lines 7 to 10, two errors are allowed.
5. The duration of viewing each sign should not exceed 3 seconds.

A more high-tech and modern way of checking can be considered the use of an optotype projector. The projectors provide a clear image of the characters and provide an opportunity to move away from the mandatory distance of 5 meters.

Types of pathologies

Here is a list of the main pathological changes that lead to a deterioration in the quality of vision:

• (hypermetropia) - with an accelerated eye axis, the image is formed behind the retina;
• (myopia) - the image is formed in front of the retina;
• - violations of the sphericity of the cornea;
• changes in visual acuity in adults.

Age-related changes in the eye include:

• presbyopia - the lens partially loses its elasticity, is not able to change the sphericity of its surface, since the ligaments lose their flexibility, and the lens itself is significantly compacted;
• - malnutrition of the lens, a decrease in its transparency;
• - increased intraocular pressure with damage to the optic nerve.

In the presence of presbyopia, a person with age has to increase the diopters in their glasses. With cataracts, the restoration of normal eye functions will be possible only with surgical intervention. In the presence of glaucoma, intraocular pressure is normalized by medication, laser or surgical methods.

In fact, you can talk for a long time about visual acuity in numbers and medical terms. However, it is much clearer to explain this category with real life examples. This will help you to navigate in terms of visual acuity much faster.

If the vision index is 1.0, a person can easily see the numbers and letters of the car number from 40 meters if there is enough light. If the visual acuity is less, then the distance from which a person will see clear, non-blurring symbols will be less. If the visual acuity is 0.4, then the number will be well read only from 16 meters, and as the distance increases, the characters will become fuzzy and gradually merge into an indistinguishable spot.

When the visual acuity is 1.0, the person sees the upper letters of the test card from a distance of 50 meters. With a visual acuity of 0.1, a person needs to move away from the table by only 5 meters.

vision improvement

To maintain visual acuity at the proper level, all measures should be taken to help maintain eye vigilance:

1. Provide the body with enough vitamin A.
2. Organize comfortable and convenient lighting in the workplace.
3. Correctly choose the color scheme of the environment in places of long stay.
4. Give up bad habits that significantly impair vision.
5. To carry out timely correction of visual acuity.

Now you know exactly what visual acuity is and how it is determined. To maintain visual acuity for a long time, follow a proper diet and exercise regularly. We hope this information was useful and interesting.

Our eyes are part of the brain brought out. A person perceives by sight more than 90% of information from the outside world. Over 60% of brain neurons are associated with vision, perception and processing of visual information.

The incoming visual information is determined in 30 centers of the visual zone of the brain responsible for the perception of color, light, length, size, etc. The lower absolute threshold of sensation for vision is the value expressed in the ability of a person to perceive a candle flame in a bright night in an airless space at a distance 48 km. A person with normal vision, taken as 1.0, is able to see the top line of the ophthalmological table from a distance of 50 m, and the 10th - from 5 m. A case of visual acuity equal to 60.0 is known! The famous Russian writer and Nobel laureate Ivan Bunin had super-sharp vision: in his youth, he could see many small stars without a telescope.
It is true that a person sees with the back of his head! The eyes are just receivers of visual information, and it is processed by the visual zone in the back of the brain. The resulting single "picture" is displayed in the frontal lobe of the brain with a gamma frequency of 40 hertz. Blows to the back of the head are especially dangerous, as such a blow can cause immediate and permanent blindness. With limited damage to the right occipital region of the brain, there may be a loss of the ability to recognize a person in person. Damage to the left occipital area can disrupt the memory of past actions.
People who suffer from migraines sometimes lose sight of part of their visual field because they temporarily lose blood flow to their visual cortex. This symptom usually begins with the fact that a small “blind” area appears in the field of vision, which gradually grows. Hence the need to maintain a healthy state of blood vessels and prevent headaches.
The visual zone of the brain, like other projection zones, does not have a clearly defined border. Between adjacent zones there are so-called "overlap zones". For example, by activating the high-frequency part of the auditory zone, we also activate the adjacent part of the visual zone. In humans, such "overlapping zones" of individual analyzers amount to 43% of the entire mass of the cortex. A significant number of neurons in the visual zone of the brain respond to sound, tactile, olfactory, and pain stimuli, and also participate in the work of the spatial orientation zone. Try to limit the influence of the "neighbors" on the visual zone, for example, plug your ears, and you will feel that the efficiency of visual perception has increased. It has been experimentally proven that with the loss of vision, a structural reorganization of the brain occurs. Our brain has enough plasticity to compensate for the loss of vision by increasing the capacity of other projection areas. Usually, a noticeable compensation occurs a month after the loss of vision, although even with a loss of vision for 90 minutes, there is an increase in the activity of the auditory areas of the brain. At one of the seminars, a listener asked for a special forces friend who lost his sight during the fighting, exercises to activate other areas of the brain (auditory, tactile, spatial orientation, etc.). Later I heard that this commando not only began to go to the store on his own, but also organized a hand-to-hand combat section at school. Of course, his strong character was also of great importance here.

Voiced specifically for Rarog Survival

Alexander LITVINOV
Photo by Roman VYAZIN

Source http://www.bratishka.ru

Speaking of certain visual impairments, we most often mean nearsightedness or farsightedness. Less often it comes to astigmatism, even less often - about color blindness. Meanwhile, no less important role in the visual perception of reality is played by the so-called contrast vision. A person can have extremely sharp eyesight and still have difficulty distinguishing objects that blend into the background.

Until recently, a routine visit to an ophthalmologist did not involve checking contrast vision, since this procedure was associated with significant difficulties and required a lot of time.

Ani Muller's technique

And now, at the Higher Technical School of Jena, a methodology has been developed that allows you to quickly and reliably carry out such control. Its author, optical engineer Anja Müller, says:

"When determining visual acuity, we do it with maximum contrast. Meanwhile, in practice, it is far from always the main thing to see the smallest details. It is much more important to see and recognize the object in general. And here it often turns out that sharp vision and good vision - not necessarily synonyms.

Research... in the buffet

Rich material for observations Anne Müller gave a buffet in her native Higher Technical School: here the white dishes almost merge with the white surface of the tables. Anyone who inadvertently knocks over a cup, although he easily reads fine print in a newspaper without glasses, almost certainly suffers from a violation of contrast vision. Typically, such a violation is caused by cataracts or clouding of the vitreous body of the eye, which, in turn, can be the result of injury, diabetes, or simply the natural aging process. Anja Müller explains:

"At opacities, the light is scattered, superimposed on the image of the object on the retina, and as a result it becomes fuzzy, blurry."

Visual acuity is determined by Landolt rings

However, retinal lesions caused by so-called macular degeneration also lead to the same effect. This feeling is familiar to anyone who wears glasses: it occurs if the glasses are dirty or badly scratched. However, for those who do not use glasses, this effect is also not new: it is observed when direct sunlight hits the screen of a computer monitor. At the same time, the image contrast drops from 80 to 40 percent, as a result of which it becomes almost impossible to make out anything on the screen. This is how people who suffer from serious impairments of contrast vision perceive all the surrounding objects. However, the diagnosis of these disorders, and especially the quantitative assessment of the degree of anomaly, until recently, were complex and expensive examinations. The methodology proposed by Anya Muller is based on a number of graphic elements of the same table that flaunts in the office of any ophthalmologist. We are talking about the so-called Landolt rings - thin circles with a small slit at the bottom, top, left or right. Just like letters and numbers, rings serve to determine visual acuity, and they are more objective because they are more difficult to guess or confuse. Anja Muller says:

"Measurement starts from the smallest ring, the slot in which the patient correctly identified at maximum image contrast. Then the contrast is gradually, step by step, reduced until the number of errors in determining the location of the slots reaches three. Thus, we set the first threshold of contrast distinguishing light sensitivity.After that, the same procedure is repeated with the next largest Landolt ring, which allows you to find the second threshold of contrast sensitivity.At the end of the measurements, we get a table from which it follows what visual acuity was necessary for the correct recognition of rings at one degree or another contrast."

Preventive contrast vision tests can help diagnose serious conditions

The larger the ring must be so that the patient can see a slit in it with low contrast, the worse his contrast vision. After conducting an extensive series of experiments, Anja Müller created a typical scheme that is entered into a computer, which allows physicians to obtain comparable standardized data. But that's not all:

"It is also important that the determination of the individual characteristics of contrast vision can also reveal a serious pathology: this diagnosis is quite sensitive."

In other words, cataracts, diabetes, or macular degeneration not only impair contrast vision, but also seem to impersonate it. That is, preventive checks of contrast vision can help diagnose serious diseases at the earliest stages.

Vladimir Fradkin, GERMAN WAVE

Vision is the highest gift of evolution, which ensures the survival and development of the highest forms of all living things, including humans. Today, thanks to advances in science, even blind people can have a satisfactory quality of life. But unfortunately, as a way of adaptation, cognition and orientation in the surrounding world, the eyes are practically irreplaceable. The reason for the loss of vision can be many abnormal conditions and processes, even some may seem unimportant or not related to vision at all. But the main causes always remain two diseases identified by ophthalmologists: clouding of the lens, persistent increased intracranial pressure. Visual impairment is a problem familiar to many. The consequence of this are age-related changes, hereditary predisposition, overwork. However, most often, poor vision is the result of a disease.

The main causes of visual impairment

There are a huge number of reasons why acute visual impairment or myopia can occur, but the main reason is the weakness of the eye muscles, they lose their elasticity and firmness, which leads to problems.

Here are the main reasons:

- frequent severe eye strain (most often this is the result of a long stay at the computer),
- softening of the muscles of the lens (due to the fact that a person often looks at an object at the same distance in connection with work, the lenses of the eye become weak),
- aging of the retina of the eye (the photosensitive pigment is damaged by destruction due to the banal aging of a person),
- circulatory disorders (the causes of such disorders are determined only by biochemical analyzes)
- viral diseases of various origins,
- pregnancy (even such a phenomenon as a simple pregnancy can cause visual impairment, especially often visual impairment occurs after complex and unsuccessful births).

Loss of clarity of vision is likely with astigmatism, farsightedness, myopia. These visual impairment problems refer to a state of change in the display capacity of the eye when an image begins to be displayed outside the retina of the eye. In addition to blurring, there is double vision and fatigue, visual impairment, in which a person at close range does not distinguish objects well, but sees well at a distance. The course of the disease myopia can proceed slowly and stop with the completion of the growth of the organism. Non-deteriorating myopia is manifested by a decrease in distance vision, is well corrected and does not require medical intervention.

short-term vision loss

- Falling vision at dusk, a symptom that develops against the background of a deficiency of trace elements, vitamins in the body.
- False myopia - switching visual impairment when looking far and near, develops as a result of overwork
- Eye fatigue is the most common cause of temporary loss of vision, resulting from prolonged eye strain. The muscles of the eyes tense, there is pain, lacrimation. Often these symptoms are aggravated by headache.

With any changes in visual acuity, it is necessary to conduct a comprehensive examination, which includes:

- measurement of visual acuity,
- determination of the refraction of the eye,
- measurement of intracranial pressure,
– ultrasound examination of the internal structures of the eye,
- diagnosis of hidden pathologies,
- determination of the production of tears,
– checking the visual field and many other necessary examinations.

The doctor who performs the eye examination is called an ophthalmologist. The most popular diagnostic method is the use of a twelve-row table of letters, rings and patterns. A person with normal visual acuity can easily distinguish the tenth line of letters or images from a distance of five meters.

How to prevent visual impairment

Prevention of visual impairment consists in following certain rules that are designed to strengthen all the mechanisms of the organs of vision.

- Workplace - do not work at a computer in a gloomy or semi-dark room. The sitting position should be even, leaning on the back of the chair, looking at the monitor should be slightly from above. The distance from the eyes to the monitor is approximately 50-70 cm. Mode of operation - every hour of work it is necessary to take a physical culture break, as often as possible look into the distance, towards the horizon or at the sky.

- Gymnastics for the eyes - you also need to regularly train your eyes in much the same way as you train yourself in the gym. The muscles of the eyes lend themselves well to training, as a result of which the tone of the eyes is removed, the eye muscles gain strength, become the most elastic. Ophthalmologists believe that eye gymnastics will be useful for all people who even rarely experience pain and pain in the eyes. Gymnastics allows you to relax after hard work, but of course it will not save you completely from diseases.

- Nutrition - a balanced composition of consumed products is necessary, all vitamins and microelements necessary for eye health must be present in the diet. Vitamin A (butter, liver, fish oil, spinach). Vitamin B (cheese, meat, milk, legumes). Source of vitamin C (citrus fruits, sea buckthorn, cabbage, tomatoes). The phosphorus necessary for the eyes is found in fish and seafood. Honey, dried apricots, melon are sources of potassium. Blueberries are especially beneficial for eye health, they contain a substance that restores visual pigment.

- Psychological conditions affecting the clarity of vision - the patient's unconscious unwillingness to see something. To correct your vision (nearsightedness), you need to get rid of the fear that caused visual impairment. It may not be one fear, but several at once. For example, vision began to fall during puberty, deteriorated more at the institute and was completely disturbed after childbirth. Each of these periods has its own fears. You need to learn how to deal with problems as they come and stop expecting the worst. Such fears are not caused by existing reality, but by your over-imagination.

Prevention of decreased visual acuity in children

Prevention of decreased visual acuity in children - it is always necessary to take care of the quality of vision in children and protect it from birth. The organ of vision matures and develops in children along with the child. In order for the child's vision not to deteriorate, reasonable visual loads, proper reading and writing, competent organization of the workplace, and healthy nutrition are necessary. To the great regret of all mankind, today glasses are more often accessories for schoolchildren.

So that the child does not enter into a huge number of children with vision problems, it is necessary to constantly be observed by an ophthalmologist. Only thanks to the vision given to us by nature, we all perceive the surrounding environment, and discover new horizons for ourselves. Everyone knows how important it is for a child to read, draw, write. If the parents do not take all measures to prevent vision, it is likely that soon it will be difficult for him to do what he loves, and he will have to spend precious time going to the doctors.

Finally

How good it is that a person, thanks to his eyesight. Has the ability to see. It's hard to imagine life in complete darkness. Prevention of improving vision is necessary for every person, regardless of whether his vision is poor or not. But to our great regret, not everyone thinks about it, but most of the problems begin precisely from the school bench. Any disease is easier to prevent than to cure. Any prevention is, first of all, a clear understanding of what you are doing and why, as well as what it will give. And of course, do not neglect the planned visit to the ophthalmologist - at least once a year. Follow the rules and take care of your eyesight!

Headache and pressure on the eyes from the inside - a symptom that should alert

Everyone has experienced a headache at least once. But if eye pains are added to this sensation, you need to beware. We will tell you about the main reasons due to which the eyes and head hurt. In most cases, you should not hesitate, but consult a doctor in a timely manner.

The reasons

Eye pain and headache can indicate a number of complications:

1. Increased intracranial pressure. In this case, the pain appears sharply, and with any tension (sneezing, coughing) it intensifies. The pains in the eyes are of a shooting character. The diagnosis is confirmed with the help of a puncture or a tomogram, while a vascular pattern appears in the fundus.
2. Intracranial hematoma. In this case, a prolonged headache is more often observed, lasting up to a week, but painful sensations in the eyes may also occur.
3. stroke risk. In old age, headaches that radiate to the eyes may indicate exactly this. When changing the position of the body, not necessarily abrupt, dizziness may occur.
4. Aneurysm. At the same time, eye and headaches last about a week, are pulsating in nature. In this case, urgent surgery is required.
5. Infectious diseases of the nasopharynx and head - sinusitis, sinusitis, meningitis, encephalitis. The pains are constant, the headaches are more pronounced than the eye pains. There is a feeling that the pain is localized in the back of the eyeball, with a change in the position of the body and head, the discomfort increases.
6. Sarcoma of the brain. Pain is accompanied by nausea, vomiting, dizziness. An urgent visit to the doctor is mandatory.
7. Eye fatigue. A long stay at a computer monitor or TV leads to excessive dryness of the eyes, there are squeezing sensations in the back of the head and temples.
8. Incorrectly fitted glasses or contact lenses. At the same time, aching headaches appear, accompanied by soreness of the eyes.
9. Nervous strain. At the same time, the headache radiates into the eyes and seems to “press” on them, you constantly want to close them, flies appear. Sensations appear due to spasm of blood vessels that feed the shoulder muscles, neck, face.
10. An increase in blood pressure is accompanied by a pressing heaviness in the head, a feeling of bulging eyes. With reduced pressure, on the contrary, there is a desire to close the eyes, the eyelids seem heavy.
11. Migraine. Accompanied by unilateral pain in the head and eyes. The sensation may be fickle, shooting. In parallel with this, limbs may become numb, pain may occur when looking at the light.
12. Allergic reaction. In this case, lacrimation, itching in the eyes, and burning are usually added.
13. Glaucoma. There is pain in the back of the head and one part of the head. The eyes turn red, visual acuity decreases, a bright halo may appear around objects. Sometimes there is nausea.
14. Other eye diseases.

How to relieve pain

Most often, pain in the eyes and head appears due to overwork, so you need to try to get rid of it with the help of simple relaxing methods, which will be described below.

You should consult a doctor when other symptoms have been added to the indicated symptoms, and the pain does not go away even after a good rest. Probably, a detailed examination will be needed to clarify the causes of occurrence.

And to relieve pain caused by fatigue, try the following methods:

1. Give your eyes a break - get enough sleep, do not work a day or two at the computer, avoid watching TV.
2. Get a relaxing head massage. Massage your head with your fingertips, moving from the middle of the occipital region to the temples, as well as working through the back of the head and neck.
3. You can try to eliminate spasmolytic pains with Spazmalgon, but if after a while the symptoms return, do not hesitate, go to the doctor.

Certain procedures will help identify the problem.

• With the help of computed tomography, you can find out about the absence of cerebral circulation disorders, check for consequences after injuries, and trace the presence of volumetric formations.
• Magnetic resonance imaging of the spine and brain allows timely diagnosis of sinusitis, stroke, intervertebral hernia, brain tumor.
• Magnetic resonance angiography determines stenotic changes, aneurysm.

Treatment of dacryocystitis in adults - a list of effective methods: massage, drops, probing

Dacryocystitis is called ophthalmic inflammation of the lacrimal sac, in which these processes develop due to clogging of the nasolacrimal canals.

What is dacryocystitis in adults?

Dacryocystitis (ICD-10 catalog code - H04.3) is an acute inflammation of the lacrimal ducts. The disease in adults is more easily tolerated than in cases with children.

Pathology occurs in adulthood quite rarely: of all those who visit an ophthalmologist, only 6% of adults are diagnosed with dacryocystitis.

Women are five times more likely to see doctors with this problem, and ophthalmologists attribute this to differences in the structure of the nasolacrimal canal in women and men.

According to statistics, the disease affects more people of the middle age group.

In the normal state, the tear produced in the lacrimal sac, having passed through such a channel, is collected in the inner corner of the eye, after which it again leaves through the channels into the nasal cavity.

If at some stage the patency of the canal becomes difficult or completely limited, dacryocystitis is diagnosed.

A photo

Causes of the disease

Unlike children, in whom this disease is congenital and occurs due to a protective film that has not broken in time, the causes of dacryocystitis in adults are different:

• pathological narrowing and closure of the nasolacrimal canal;
• viral or bacterial diseases that contribute to the development of edema that compress the tear ducts;
• fractures of the bones of the orbit of the eye or nose;
• violation of the integrity of the lacrimal canals due to trauma;
• entry into the lacrimal canals of foreign bodies;
• polyps in the nasal cavity.

Symptoms of dacryocystitis in adults

Symptoms of dacryocystitis in adults are similar to those of this disease in children.

In particular, uncontrolled tearing or its absence may be observed, the area of ​​​​the lacrimal sac swells noticeably, the eyelids and corners of the eyes acquire a red tint.

Lachrymation may stop as early as a day after the tear ducts become clogged.

And after a few hours, instead of tears, purulent exudate begins to stand out abundantly or not very much.

If you press on the lacrimal sac, the patient experiences pain, and if the disease occurs in an acute form, such pains can be aching and very sensitive.

In the chronic form, the pain syndrome may be completely absent.

Acute and chronic form

The two types of disease can be distinguished by the symptoms, and in the acute form the following symptoms can be observed in the patient;

• increase in body temperature;
• swelling in the lacrimal sacs;
• narrowing of the palpebral fissure;
• swelling of the eyelids is possible;
• pain in the orbit of the eye;
• manifestation of general symptoms of intoxication of the body.

The tumor, which is well palpable in the area of ​​the lacrimal sac, may begin to be dense to the touch, but after a few days it begins to soften, and the swelling subsides.

During this period, an abscess is formed, which can spontaneously open, and due to the outflow of pus from it, swelling decreases.

In the chronic form, the patient does not experience pain, but at the same time he has severe constant lacrimation, and the swelling in the area of ​​the lacrimal sac turns into a tumor, when pressed on which pus begins to flow from the lacrimal ducts.

Diagnostics

Diagnosis in adults begins with the delivery of a general analysis of urine and blood, after which the specialist takes a smear for bacterial culture.

Sometimes such disorders can cause dacryocystitis, and in these cases, surgery is often necessary.

Be sure to carry out a tubular test, during which a coloring solution of collargol is instilled into the patient's eyes.

After such an instillation, the patient's eyeball is observed to determine whether this substance goes into the tubules. If this does not happen, this indicates their blockage.

Treatment

Treatment of dacryocystitis in adults in the early stages involves exclusively conservative treatment: this is a standard tubular massage and the use of antibacterial eye drops.

If this does not help, mechanical cleaning of the canals is required using a special surgical probe.

Massage for dacryocystitis

The patient can perform the massage on his own by pressing on the outer corner of the eye with his fingertip and gradually moving to the inner corner without stopping the pressure.

The video tells in detail and shows how to do the massage yourself:

Drops

Therefore, the use of the following eye drops is considered more effective:

• fusidic acid;
• cefuroxime;
• chloramphenicol;
• tetracycline;
• doxycycline.

In the event that an abscess is already forming, physiotherapy procedures help well, although it is preferable to perform an operation to open the abscess.

sounding

If conservative treatment does not give results, experts prescribe probing.

For newborns, this method is not used, but for children from a year old, and even more so for adults, this method can help.

When performing such a procedure, local anesthesia is performed, after which the doctor inserts a hard probe into the lacrimal canal, which breaks through the accumulated plugs and expands the canals.

Sometimes it turns out to get by with just one procedure, although every third case requires repeated intervention after a few days.

In general, the prognosis for this procedure is favorable, and in 9 out of 10 patients, after probing, the circulation of fluids in the lacrimal tubules is restored.

Possible consequences and prognosis of treatment

Dacryocystitis refers to those types of ophthalmic pathologies that cannot be left to chance in the hope that the disease will not progress over time.

If the lacrimal sac and the lacrimal canal become inflamed, this in itself indicates the presence of pathogenic microflora in the foci of inflammation.

If dacryocystitis is not treated in time, the following diseases may develop as complications:

Sometimes the attachment of a corneal ulcer is diagnosed. The consequence of this is the development of walleye.

If the thorn does not form, corneal ulceration can lead to perforation, which leads to subatrophy of the eye.

These are quite serious complications, in which even loss of vision is an optimistic prognosis: most often the development of such processes leads to death.