How to quickly and easily test binocular vision at home? Binocular vision - research, treatment of disorders

Vision, which allows a person to see equally well with both eyes, to distinguish the shape of an image and the approximate distance to it, is called binocular in ophthalmology. If it is not broken, then a person can see not only objects in front of him, but also from the side, above and below. Binocular vision is called stereoscopic vision and begins to develop in infancy. A child at the age of two can already see well with both eyes at the same time, and the full formation of the type of vision in question ends by the age of 16.

Binocular vision allows you to clearly see an image, determine the shape, size and distance to an object.

This type of vision is not formed in all people. In order for binocular vision to be within normal limits, the following factors must be present:

• work of central and peripheral nervous system without pathologies and disorders;
• coincidence of degrees of refraction in both eyes;
• the same shape and size of the corneal layer in both eyes;
• normal structure of the lens and retina of the eye;
• absolute symmetry of the eyeballs (their location may change due to injury or a growing tumor);
• equal level of vision in the eyes;
• precise work muscle tissue organs of vision;
• optical environment without pathologies in both eyes.

Only the presence of all the above factors creates conditions for normal development binocular vision. The “loss” of one of the conditions leads to disturbances in the vision of images.

In addition, it plays an important role proper development and formation of the cerebral cortex. Binocular vision will be formed only if the specified part of the brain is able to simultaneously perceive two “pictures” from both eyes, “merge” them together and send necessary information V visual department brain. Therefore, children with congenital pathologies cerebral cortex, vision is affected.

How to test binocular vision

Any examinations must be carried out by doctors; ophthalmologists, using special devices, can determine in a matter of minutes whether binocular vision is present or whether there are any disturbances. But there are several methods that allow you to check at home.

Wrong reading

A person is given a pencil, which should be placed at the tip of his nose. Both eyes focus on him. A sheet of printed text is placed in front of the person being tested and the person is asked to read it. While reading, you should not move your eyeballs, move a piece of paper with text, or move your head.

If binocular vision is formed and developed normally, then a person can easily make out and read the text. This is done thanks to lateral vision, as well as the ability to see from below. In the cerebral cortex, the images merge into a single picture that can be distinguished without difficulty.

Rolled sheet (according to Sokolov)

A person is given a sheet of paper rolled into a tube or any hollow cylinder to one eye. You need to focus your gaze on any object in the distance, then place the palm of your hand in front of your second eye at the level of the outer edge of the cylinder. If binocular vision works within normal limits, then a person will describe the resulting image as “a palm with a hole in the middle, through which an object is clearly visible.”

Four point test

This method of testing binocular vision is considered the most accurate. Four objects are placed in front of the person being tested: red, white and two green - these could be, for example, cubes. Then you need to put on glasses with different lenses, one of which is red and the other green.

With normally formed vision of the type in question, a person will be able to distinguish both objects and their true colors. If there are violations, he will get confused in the colors of objects and will not see white at all.

Kalf's Experience

The person being tested is given two pencils, one of which is located horizontally and the other vertically. You need to connect these two pencils, bring one to the other so that they touch. If binocular vision is impaired, then the person will not be able to complete the task, since he cannot adequately assess the distance between the pencils.

In an ophthalmology office, the level of the type of vision in question is checked using a slit lamp, monobinoscope, ophthalmoscope, and autorefractometer.

Possible violations

Binocular vision can be impaired for a variety of reasons:

• brain stem pathologies;
• frequent and complicated infectious diseases;
• chronic poisoning;
• pathological changes in the muscles of the organs of vision;
• diseases of the orbital cavity;
• neoplasms of the brain and eyes.

Most often, binocular vision impairment occurs, which is treated by correction with glasses or lenses, special gymnastics for the eyes, physical therapy or surgery.

Prevention of binocular vision disorders

To avoid disturbances of this type of vision, you need to adhere to the following recommendations of the ophthalmologist:

• eye strain should be moderate;
• exercises for the visual organs should be performed regularly, especially in the case of chronic eye strain;
• strict adherence to sleep and wakefulness;
• giving up alcohol;
• timely contact with ophthalmologists for preventive examinations and diagnosis of eye diseases.

Binocular helps to navigate in space and guide full life. You just need to make some efforts to preserve it so that you don’t have to deal with treatment and correction later.

Binocular vision is the norm for everyone healthy person. This is an opportunity to see the world two eyes with the formation of a single visual image. It gives volume and depth of perception, the ability to navigate in space, distinguish objects, and understand how they are located. Binocular visual function is mandatory for the profession of driver, pilot, and surgeon.

To understand the difference between stereoscopic and binocular vision, you need to know that stereoscopy is one of the qualities of binocular vision, which is responsible for the three-dimensional perception of objects.

A newborn does not have binocular vision because he has floating eyeballs. Patients suffering from diseases of the retina or lens of the eye do not have such vision. In any case, to answer the question of whether a person has the ability to see with both eyes, special testing is carried out.

So, binocular is called vision with both eyes, and monocular - with one. Only the ability to see with two eyes gives a person the opportunity to adequately perceive objects around him using the stereoscopic function. The eyes are a paired organ and their joint work allows us to evaluate everything that is around in terms of volume, distance, shape, width and height, and to distinguish colors and shades.

Monocular vision allows you to perceive environment only indirectly, without volume, based on the size and shape of objects. A person who sees with one eye will not be able to pour water into a glass or thread a thread into an eye.

Only both types of vision create full picture visible space and help navigate it.

Mechanism of action

Stereoscopic vision is created using the fusion reflex. It helps to combine two images from both retinas into one image by merging them. The retinas of the left and right eyes have identical (corresponding) and asymmetrical (disparate) points. For volumetric vision, it is important that the image falls on identical retinal currents. If the image falls on disparate points of the retina, double vision will occur.

To obtain a single image, several conditions must be met:

1. the images on the retina must be identical in shape and size;
2. should fall on the corresponding areas of the retina.

When these conditions are met, a clear image is formed in a person.

Formation of visual ability

From the first day of birth, the movements of the baby's eyeballs are not coordinated, so there is no binocular vision. After six to eight weeks from birth, the child can already focus on an object with both eyes. At three to four months the baby develops a fusion reflex.

A child begins to see fully with both eyes by the age of twelve. It is because of this that strabismus () is typical for children who go to a nursery or kindergarten.

Infographics about the formation of binocular vision in children (from birth to 10 years)

Signs of normal binocular vision

In healthy people it is characterized by a number of signs:

• A fully formed fusion reflex, which makes it possible to produce bifoveal fusion (fusion).
• The coordinated functioning of the oculomotor muscle tissues, which ensures the parallel position of the eyes when looking at distant objects and the convergence of the visual axes when viewing nearby objects. In addition, it ensures simultaneous eye movement when observing a moving object.
• Finding visual apparatus in one frontal and horizontal plane. If one eye becomes dislodged as a result of injury or inflammation, the symmetry of the fusion of visual fields becomes distorted.
• Visual acuity is at least 0.3 – 0.4. Since such indicators are quite enough to form an image with clear outlines on the retina.
• Both retinas should have the same image size (iseikonia). With different eye refractions (anisometropia), unequal images appear. To maintain the ability to see with both eyes, the degree of anisometropia should be no more than three diopters. It is important to take this parameter into account when selecting glasses or contact lenses. With a difference between the two lenses of more than 3.0 diopters, even with high visual acuity, a person will not have binocular vision.
• Cornea, lens and vitreous must be completely transparent.

There is no stereoscopic vision with cataracts

Testing binocular and monocular vision

Several methods have been developed to test whether a person has binocular ability:

Sokolov's experience

The Sokolov experiment or “hole in the palm”

This technique has another name – “hole in the palm”.

What should be done:

The essence of the technique is that a folded sheet of paper is placed to the patient’s right eye, through which he must examine distant objects. At that time left hand I extend it so that my palm is at a distance of 15 cm from my left eye. That is, a person sees a “palm” and a “tunnel”. If there is binocular vision, then the images overlap each other and it seems as if there is a hole in the palm through which we see the picture.

Another name for the technique is a miss test.

In order to determine the presence of binocular vision using this method, you will need two long objects (for example, 2 pens or 2 pencils). But in principle, you can use your own fingers, although the accuracy will decrease slightly.

Miss test (Kalf method)

What to do:

• Take the pencil in one hand and hold it horizontally.
• In your other hand, take the second pencil and hold it vertically.
• Place them at different distances, move your hands in different sides to confuse yourself, and then try to bring the ends of the pencils together.

If you have stereoscopic vision, then this task is quite simple. Without this ability, you will miss. To verify this, you can repeat the same experiment with with one eye closed. Since when only one eye is working, 3D perception is disrupted.

"Reading with a Pencil"

You will need: a book and a pencil.

Instructions:

• You need to take a book in one hand and a pencil in the other, placing it against the background of the book’s pages.
• The pencil should cover some letters.
• If binocular ability is present, the patient can read the text even despite the obstacle. This happens by merging the images in the review.

Most precise research binocular vision is performed using a four-point color test. It is based on the fact that visual views can be separated using color filters. To do this you need two objects that are colored in green color and one each in red and white. The subject needs to wear glasses, with one red and the other green glass.

• If the subject has binocular vision, he will only see red and green colors of objects. The object white will appear red-green because perception occurs with both eyes.
• If one eye is dominant, then the white object will take on the color of the lens opposite that eye.
• If the patient has simultaneous vision (that is, the visual centers receive impulses from one or the other eye), he will see 5 objects.
• If the subject has monocular vision, then he will perceive only those objects that are colored the same color as the lens in the seeing eye, without reading a colorless object that will be the same color.

Strabismus

Strabismus (strabismus, heterotropia) is a disease characterized by unformed binocular vision in both eyes. This happens because one eye deviates to one side or another due to weakness of the muscular system.

Types (classification) of strabismus

Strabismus can provoke weakening of one or more oculomotor muscles, subdivided into:

• Convergent (esotropia) – with it there will be a deviation eyeball to the bridge of the nose;
• Divergent (exotropia) – deviation of the organ of the visual apparatus occurs towards the temporal region of the head;
• Unilateral - only one eye deviates;
• Alternating – alternating deviation of both eyes occurs.

Classification of strabismus according to the form of eye deviation

If the patient has binocular vision but one or both eyes are deviated from normal position this may indicate that he has a false (imaginary or hidden) strabismus (pseudostrabismus).

Imaginary strabismus

It is characterized by a large discrepancy between the visual and optical axes. Also, the centers of the cornea can shift to one side. But treatment in this case is not required.

Hidden strabismus

This type of strabismus can occur periodically when the gaze is not fixed on any object.

Checked this type pathology as follows:

The patient fixes his gaze on one moving object and covers his eye with his hand. If the eye, which is covered, follows the trajectory of the object, then this indicates hidden strabismus in the patient. This disease does not require treatment.

Binocular vision is the norm for a healthy person and the basis of his life, both in everyday life and in professional life.

In order to form a three-dimensional image in central structures brain, it is necessary to merge two images that were received from both eyes into a single whole. This is called binocular vision.

Binocular vision appears through the process of merging images that were obtained from the surface of both eyeballs. This helps to perceive objects in volume, that is, it provides depth to the image.

And due to the operation of the binocular vision mechanism, you can fully perceive the world around you and determine the distance to objects and between them. The so-called stereoscopic vision is an achievement of evolutionary transformations. With monocular vision, you can only obtain information about the width and height of an object, its shape, but flat vision does not make it possible to evaluate mutual arrangement objects relative to each other.

In addition to the listed advantages, binocular vision is responsible for expanding the visual fields, as a result of which you can perceive objects more clearly. This, in turn, is accompanied by an increase in visual acuity. Only if you have good binocular vision is it possible to work in several specialties, in particular, as a driver, surgeon, pilot, etc.

Mechanism of binocular vision

The fusion reflex is a fundamental mechanism of binocular vision. In this case, the images that were formed in the retinal plane merge into a single picture with stereoscopic characteristics. This fusion occurs at the level of the cerebral cortex.

For the image to become unified, it is necessary to match the images obtained from the right and left retinas. This takes into account the size and shape of the image, as well as the area where it is projected onto corresponding identical areas of the retina. Each point in the retinal plane has its own corresponding point on the opposite side. Asymmetrical areas are called non-identical points, or disparate. When image points fall into these disparate points of the retinal plane, binocular vision becomes impossible. Instead of merging the image, doubling occurs.

In newly born children, coordinated movement of the eyeballs is not possible, and therefore binocular vision is absent. At about one and a half months, babies develop the ability to fix their gaze with two eyes, and at 3-4 months we can already talk about stable binocular fixation. The fusion reflex is formed only by 5-6 months, and full binocular vision - only by 12 years. In this regard, it is more often present in patients of preschool age.

To form normal binocular vision, several conditions must be met:

• Ability to fusion (bifoveal fusion).
• Consistency in everyone's work muscle fibers, responsible for eye movement. They should ensure a parallel position of the eyeballs while the patient looks into the distance. When the gaze moves to a closer position, a proportional convergence of the visual axes occurs. This process is called. Also, the extraocular muscles must respond to the associated movements of the eyeballs directed towards the object being studied.
• The visual acuity of each eye should not be less than 0.3-0.4, which is sufficient to form a clear image.
• The eyes should be located in the same horizontal and frontal plane. If, as a result of injury, tumor, inflammation or surgery, a change in symmetry occurs, then the merging of images becomes impossible.
• Images projected onto the retinal plane must be of this size (iseikonia). With different sizes of objects on the retina we're talking about about, which occurs when the refraction of the two eyeballs is different. In order for binocular vision to be present, the degree of anisometropia should not exceed 2-3 diopters. This must be taken into account when choosing, despite good visual acuity, binocular vision will be absent.
• Also a necessary condition binocularity is the transparency of the eye media (,), absence pathological changes the perceptive apparatus (retina) and the conduction system (optic tract, chiasm, cerebral cortex, subcortical centers).

Our binocular vision specialist

How to check?

There are several diagnostic tests available to test binocular vision:

• Sokolov's experiment (hole in the palm) involves placing a tube (this can be a piece of paper rolled into a tube) to the patient's eye. The subject must look through it into the distance. From the outside open eye The palm of your hand is placed at the end of the tube. If there are no problems with binocular vision, then due to the superimposition of images the patient perceives the image as a hole in the center of the palm (occurs due to the superposition of images).
• The slip test (Kalf experiment) requires two pencils (or two knitting needles) to perform. The patient should hold the needle (pencil) in a horizontal plane on outstretched arm, in this case it is necessary to get its end into the second knitting needle (pencil), located in the vertical plane. If the patient has normal binocular vision, then this task will not cause difficulties. If binocular vision is absent, then the subject constantly misses. For accurate diagnosis The test should be carried out with one eye closed. In this case, the patient must miss.
• The pencil reading test is carried out as follows: a pencil is placed at a distance of several centimeters from the tip of the nose, which will cover some of the letters. If binocular vision is preserved, then there will be no problems with reading due to the superimposition effect. The subject will be able to read without changing head position. IN otherwise You will have difficulty reading closed letters.
• For a more detailed diagnosis, you can use a four-point color test. At the same time, the visual fields of the right and left eyes are separated, which becomes possible thanks to the use of color filters. Four objects are also used (two green, one white and one red). Glasses with different glasses (red and green) are placed on the patient's eyes. If the patient has binocular vision, then he is able to distinguish between red and green objects. What is colorless will be colored red-green as it will be perceived by both eyes. If there is a pronounced dominant eye, the colorless object will be colored in the color of the corresponding glass (green or red). In the case of simultaneous vision, if the higher structures perceive data from both eyes, the patient will see five circles. In the case of monocular vision, the patient will be able to recognize only those objects that match the color of the glass on the perceiving eye, as well as a colorless object (it will turn into the corresponding color).

Binocular vision and strabismus

If the patient has strabismus, then binocular vision is absent. This is due to the fact that the eye deviates, and the axes do not converge in the studied area. The main goal of treating patients with strabismus is to restore normal binocular vision.

Based on the presence or absence of binocular vision, it is possible to distinguish imaginary, apparent and hidden strabismus (heterophoria) from real,

Between the optical axis, which passes through the central region of the cornea and the nodal point, and the visual axis, which begins in the fovea macular spot and is directed towards the object being studied, there is a deviation of about 3-4 degrees. With imaginary strabismus, the angle between these axes becomes larger and can reach 10 degrees. Wherein central regions The corneas are shifted to the side, which leads to the effect of imaginary strabismus. Along with this, with imaginary strabismus, binocular vision is preserved. This feature allows you to establish a correct diagnosis, which is important, since imaginary strabismus does not require treatment.

With hidden strabismus, deviation of one of the eyes occurs when the muscles relax, that is, in the case when there is no fixation of gaze on an object. Heterophoria can be determined by the installation movement of the eyeballs. When fixating a gaze, a person must cover his eye with his palm. In the presence of hidden strabismus, the closed eye will deviate to the side. If you remove your palm, the eye makes an adjustment movement (if you have binocular vision). Heterophoria should also not be treated, as should imaginary strabismus.

IN medical center At the Moscow Eye Clinic, everyone can undergo an examination using the most modern diagnostic equipment, and based on the results, receive advice from a highly qualified specialist. The clinic is open seven days a week and operates daily from 9 a.m. to 9 p.m. Our specialists will help identify the cause of vision loss and conduct competent treatment identified pathologies.

In our clinic, consultations are carried out by the best ophthalmologists with extensive experience. professional activity, the highest qualifications, a huge amount of knowledge.

You can find out the cost of a particular procedure or make an appointment at the Moscow Eye Clinic by phone in Moscow 8 (499) 322-36-36 (daily from 9:00 to 21:00) or using the online registration form.

Since childhood, many people have been interested in why they need two eyes if they can see with just one. But few adults can formulate an exact answer. The whole secret is that the two images perceived by the eyes seem to overlap each other. We get the opportunity to see the world around us more fully and voluminously.

Monocular and binocular vision differs from each other in many ways.

Binocular or, as it is also called, stereoscopic vision in humans is simultaneous vision with two eyes. Images focused on the retinas generate nerve impulses, which enter the visual centers of the brain. After processing the information, the brain creates a complete three-dimensional image of the surrounding world. The binocular vision apparatus makes it possible to orient oneself quite well in space, to view objects three-dimensionally, and also to accurately estimate the distance to objects.

As studies show, due to the lack of coordination of movements in the visual organs, a newborn baby is not yet able to see binocularly. Consistency begins to appear only at 6-8 weeks of life.

By the age of six months, stable fixation of objects with both eyes at the same time appears, and only by the age of 10 the formation process is finally completed.

Basics of stereoscopic formation

Not every person is capable of binocular perception, for the formation of which it is necessary:

What is the fusion reflex

Two images obtained on the retinas of the eyeballs are combined into one image due to such a property of the nervous system as the fusion reflex. To merge both images into one three-dimensional image, it is required that the image obtained on the retina of one eye matches in shape and size with the image from the other and falls on identical points of the retina. If the image falls on asymmetrical areas of the retina, then the pictures will not merge into a single image and the world in the eyes will bifurcate.

Monocular vision in humans

Unlike humans, the eyes of some animals are designed and positioned in such a way that fusion is impossible. Perception using one eye, when the pictures do not add up, is called monocular vision. Binocular vision is inherent in humans and many mammals, and monocular vision is present in all birds (except owls), as well as in some species of fish and other animals.

At various pathologies Monocularity also occurs in humans. Such abnormalities can be identified and are often treatable.

Basic verification methods

In ophthalmology, there are many tests to check the visual system for binocularity and determine its violations.

Definition of strabismus

One of the most well-known pathologies of binocularity is strabismus. This is a constant or periodic deviation of the visual axis of one or both eyes from the common point of fixation, accompanied by a violation of stereoscopicity and a significant decrease in visual acuity in the squinting eye.

There are real and imaginary strabismus. With imaginary stereoscopic vision, stereoscopic vision is not impaired and treatment is not necessary.

Lack of binocular vision can be caused by a number of reasons. But when timely application This problem can usually be resolved successfully by visiting an ophthalmologist.

Attention, TODAY only!

Binocular vision occurs when both eyes participate in the visual act and merge two monocular images into a single visual image. Each eye sees the object of fixation from slightly different positions; the images in the right and left eyes are shifted transversely relative to each other (disparate).

The phenomenon of transverse disparation in binocular vision is the basis of depth vision (in-depth assessment of the visual image). Stereoscopic vision reflects the ability to judge depth in the presence of stereoscopic instruments and devices.

Binocular vision is based on the mechanism of retinal correspondence - the innate property of the foveal and symmetrically distant areas (corresponding zones) of the retinas of both eyes to a single perception of the fixed object. The merging of two monocular images during binocular vision also occurs under conditions of convergence and separation of the visual axes to a certain limit, which is possible due to fusion reserves (fusion reserves).

When the image of an object hits different distanced (non-corresponding, disparate) areas of the retinas, a single visual image does not form. The images are perceived as double and simultaneous vision occurs, which is characteristic of strabismus. To get rid of double vision, the squinting eye is gradually inhibited and the other eye becomes functionally dominant - monocular vision develops.

Formation of binocular vision

Binocular vision begins to develop from early childhood and is formed by 1-2 years. It gradually develops, improves, and by the age of 6-8 years stereoscopic vision is formed, reaching full development by the age of 15.

To form binocular vision, the following conditions are necessary:

• equal visual acuity in both eyes (not lower than 0.4 in each eye);
• the same refraction (degree of farsightedness or myopia) in both eyes;
• symmetrical position of the eyeballs; .
• equal image sizes in both eyes - iseikonia.
• Normal functional ability of the retina, pathways and higher visual centers.
• The location of the two eyes in the same frontal and horizontal plane

It should be noted that with an inequality of image sizes (anizeikonia) of 1.5-2.5%, unpleasant subjective sensations in the eyes (asthenopic phenomena) occur, and with aniseikonia of 4-5% or more, binocular vision is practically impossible. Images of different sizes occur with anisometropia - different refraction of the two eyes.

When one eye is displaced during injury, as well as in the case of the development of an inflammatory or tumor process in the orbit, the symmetry of the combination of visual fields is disrupted, and stereoscopic vision is lost. If one of these links is disrupted, binocular vision may be upset or not develop at all, or it may become monocular (vision with one eye) or simultaneous, in which impulses from one or the other eye are perceived in the higher visual centers.

Monocular and simultaneous vision allows you to get an idea only of the height, width and shape of an object without assessing the relative position of objects in space in depth.

Characteristics of binocular vision

An important condition for the existence of binocular vision is the balance of the tone of the extraocular muscles.

• Orthophoria is an ideal balance of the tone of the extraocular muscles.
• Heterophoria is a hidden imbalance in the tone of the oculomotor muscles, detected in 70-75% of mature people with binocular vision. There is esophoria (with a tendency to reduce the visual axes) and exophoria (with a tendency to separate them). Heterophoria can cause asthenopia, decreased visual performance, and in some cases, strabismus.

The main qualitative characteristic of binocular vision is deep stereoscopic vision of an object, which allows one to determine its place in space, to see in relief, depth and volume. Images of the external world are perceived as three-dimensional. With binocular vision, the field of view expands and visual acuity increases (by 0.1-0.2 or more).

With monocular vision, a person adapts and orients himself in space, assessing the size of familiar objects. The further away an object is, the smaller it appears. When you turn your head, objects located at different distances move relative to each other. With such vision, it is most difficult to navigate among nearby objects, for example, it is difficult to get the end of a thread into the eye of a needle, pour water into a glass, etc.

The lack of binocular vision limits a person's professional suitability.

Diagnostics

Indications

Exist the following readings to assess binocular vision:

• professional selection (flight professions, precision work, driving Vehicle and etc.);
• planned preventive examinations of children and adolescents before school and during training;
• pathology of the oculomotor system (strabismus, nystagmus), asthenopia, occupational ophthalmopathy.

Contraindications

• Acute inflammatory diseases eye.

To assess binocular vision, the following are sequentially carried out:

• study of the presence of binocular, simultaneous or monocular vision using haploscopic methods, based on the principle of dividing the visual fields of both eyes using color (four-point, or Wars test), raster (Bagolini test) or polaroid (four-point Polaroid test) haploscopy;
• for strabismus - testing using the method of sequential visual images (according to the Chermak principle);
• assessment of binocular functions (fusion ability) on a synoptophore (under mechanical haploscopy);
• assessment of depth vision (threshold, acuity);
• assessment of stereoscopic vision (stereo pair);
• phoria research.

Some simple ways determination of binocular vision without the use of instruments.

Binocular coordination of eye movements

Movements of the eyeball are carried out by six external ocular muscles, which are innervated by three cranial nerves: oculomotor (III pair), trochlear (IV pair) and abducens (VI pair). Therefore there are many different nerve connections between cortical visual areas and oculomotor centers in the brainstem.

Thus, signals from area 18 of the cortex go to the superior colliculi (superior colliculus), which control neurons that control the direction of gaze. Neurons that control horizontal eye movements are located predominantly in the paramedian reticular formation pons, and the neurons that control vertical eye movements are in the reticular formation of the midbrain. From here their axons go to the neurons of the nuclei of the abducens, oculomotor and trochlear nerves, as well as to the motor neurons of the upper cervical part spinal cord. In this regard, eye and head movements are coordinated with each other.

The level of excitation of the oculomotor centers is regulated by various visual areas of the brain: the superior colliculi, the secondary visual cortex, the parietal cortex (mainly its area 7). When the paramedian reticular formation of the pons is damaged, horizontal rotation of the eyes in the direction where the pathological focus of the brain is located is difficult. Damage to the reticular formation of the midbrain makes it difficult to move the eyes vertically.

For stable vision of the object in question, the eye must constantly make small movements, which can be of three types:

• tremor - high-frequency (30-150 Hz) oscillations around the fixation point with a very small amplitude (up to 17 arc seconds),
• drift - slow (up to 6 arc minutes per 1 s) sliding of the gaze from a given direction (by an amount from 3 to 30 arc minutes),
• microsaccades (microjumps) - rapid movements of the gaze from 1 to 50 arc minutes.

Drift helps restore the visibility of the image on the retina, and microsaccades help restore the given direction of gaze.

Thus, the visual pathway is represented as a very complex multi-storey hierarchical network of neural structures, becoming significantly more complex towards the cerebral cortex. Functionally, this helps to isolate individual, increasingly complex elements of the visual image. The final functional stage visual pathway is the synthesis of visual images and their recognition by comparison with the existing stock of visual images stored in memory.

Various visual impairments that occur when the visual analyzer is damaged manifest themselves as changes in quantitative characteristics visual functions, and in changes in the qualitative characteristics of visual functions.

Lesions at each level (division) of the visual analyzer are manifested by the formation of a fairly characteristic symptom complex. This helps to establish topical and nosological diagnoses.