Ways to restore binocular vision. The state of binocular vision: how to check? Two Pencil Test

The patient is offered test pictures-objects created in pairs. The set contains objects for three types of tests:

for combination;
to merge;
for the stereo test.

What is determined using a synoptophore:

bifovial fusion (binocular fusion);
functional scotoma (suppression, manifested regionally or totally), its size and location are also determined;
positive or negative fusion reserve (line split test);
stereo effect.

Synoptophore allows you to "look" into the picture that only the patient sees. According to the descriptions that the specialist receives from the subject, one can understand what hinders normal vision patient, give a prognosis for the possibility of recovery and prescribe treatment after verification.

Depth Vision Assessment

The test is carried out without separation of the visual fields, the eyes are in their natural state, the gaze is directed at the device (for example, the device of Howard-Dolman, Litinsky and others). An example of a study on the so-called three-stick test. Three vertical rods are located on one level: two extreme and one in the center, which is movable. The middle one moves away or approaches, the task is to catch the moment of displacement relative to the two extreme rods. The assessment is made from 50 cm - for near, and from 5 meters for distance. The results are evaluated in angular terms (or linear). Visual Impairment Check for Patients middle age estimate from 3-6 mm near, and from 2-4 cm away.

Stereoscopic vision assessment

A system of tests is carried out using polaroid vectograms with special glasses: the effect of the picture is stereoscopic. The specialist has a table to check the correctness of the distance: the patient says what he sees, the doctor compares the result.

The threshold of stereoscopic perception is revealed on tests:

Flying fly.
Lang test.
Pulfrich lens stereoscope.
screening method.

Definition of phoria

Phoria - deviation or reversal of the eyes from the axes, anomaly. Lack of coordination between the eyes.

To determine phoria, special tests are used:

Maddox test;
Graefe's test.

Special kits, using which an ophthalmologist can determine the nature of visual impairment in a person. The evaluation system is simple: the specialist knows what results will be with normal binocular function, and what the patient with pathology sees.

According to the results of the research, heterophoria, esophoria or exophoria is diagnosed, the magnitude of phoria is estimated.

Get tested

If you know that the last examination by an ophthalmologist took place a long time ago, check your visual acuity again. With age, muscles can lose tone and the ability to focus as clearly as in youth. Perceptual disturbance may result from general condition body or due to working conditions and lifestyle.

That is, if you once saw everything well thanks to binocular vision, perhaps the diagnosis and examination of the eyes will now show that it is time to take on the correction. Violations in initial stage really do not require treatment and may be subject to correction. To do this, you need to know the appropriate exercises, observe living conditions, treatment for poor eyesight.

If you see everything well, then only an examination can confirm whether you really see binocularly. The initial disorder may not be assessed subjectively. A person notices that he began to see worse when the violation is already quite serious. Even in this case, the specialist will choose the best device for diagnosis and treatment, prescribe glasses with correct settings lenses.

Fundamentals of the formation of stereoscopicity

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

What is a fusion reflex

Two images obtained on the retinas of the eyeballs are combined into one image due to this property. nervous system, as fusion reflex. To merge both images into one three-dimensional image, it is required that the image obtained on the retina of one eye coincides 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 split into two.

Monocular vision in humans

Unlike humans, the eyes of some animals are designed and arranged in such a way that fusion is impossible. Perception with 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 in all birds (except for the owl), as well as in some species of fish and other animals.

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

Basic verification methods

In ophthalmology, there are many tests to check visual apparatus on binocularity and the definition of 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 common point fixation, accompanied by a violation of stereoscopicity and a significant decrease in visual acuity in the squinting eye.

There is real and imaginary strabismus. With an imaginary stereoscopic vision not disturbed and treatment is optional.

The lack of binocular vision can be caused by a number of reasons. But at timely handling to the ophthalmologist this problem is usually solved successfully.

Attention, only TODAY!

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

The newborn does not have binocular vision because it has floating eyeballs. There is no such vision in patients suffering from diseases of the retina or the lens of the eye. In any case, in order to answer the question of whether a person has the ability to see with two eyes, special testing is carried out.

So, binocular vision is called both eyes, and monocular - 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 you to evaluate everything that is around in terms of volume, distance, shape, width and height, 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, thread a thread into his eye.

Only both types of vision create a complete picture of the foreseeable space and help to navigate in it.

Mechanism of action

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

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

images on the retina must be identical in shape and size;
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 the date of birth, the child can already focus on the subject with both eyes. At three to four months, the baby develops a fusion reflex.

See with both eyes in full the child begins at the age of twelve. It is because of this that strabismus () is typical for children who go to a nursery or kindergarten.

Infographics on 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 symptoms:

Fully formed fusion reflex, which makes it possible to produce a bifoveal fusion (fusion).
The coordinated functioning of the oculomotor muscle tissues, which provides a parallel arrangement of the eyes when looking at distant objects and convergence of the visual axes when considering close objects. In addition, it provides simultaneous eye movement when observing a moving object.
The presence of the visual apparatus in the same frontal and horizontal planes. If one eye is displaced as a result of injury or inflammation, there is a deformation of the symmetry of the fusion of visual views.
Visual acuity 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 refractions of the eyes (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 consider this parameter when selecting points or contact lenses. With a difference between the two lenses greater than 3.0 diopters, even with high visual acuity, the person will not have binocular vision.
The cornea, lens and vitreous must be completely transparent.

No stereoscopic vision with cataract

Checking binocular and monocular vision

To check whether a person has binocular ability, several methods have been developed:

Sokolov's experience

Sokolov's experience or "hole in the palm"

This technique has a different name - "hole in the palm."

What should be done:

The essence of the technique is that a folded sheet of paper is attached to the patient's right eye, through which he must examine distant objects. At that time left hand I stretch it so that the palm is at a distance of 15 cm from the left eye. That is, a person sees a “palm” and a “tunnel”. If there is binocular vision, then the images are superimposed on 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 slip 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.

Slip test (Kalff method)

What to do:

Take a pencil in one hand and hold it horizontally.
In your other hand, take the second pencil and hold it vertically.
Separate them at different distances, move your hands in different sides to confuse yourself, and then try to bring the tips 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 closed eye. Since when only one eye is working, 3D perception is disturbed.

"Reading with a Pencil"

You will need: a book and a pencil.

Instruction:

You need to take a book in one hand, and a pencil in the other, placing it against the background of the pages of the book.
The pencil should cover some of the letters.
In the presence of binocular ability, the patient can read the text even in spite of the obstacle. This happens due to the merging of pictures in the review.

Most precise research binocular vision is produced 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 items that are painted in green color and one each in red and white. The subject must be put on glasses, with one red and the other green glass.

If the subject has binocular vision, then he will see only the red and green colors of objects. The object is white color will appear red-green because the perception is in 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 (i.e., 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 in the same color as the lens in the seeing eye, without reading a colorless object that will be of the same color.

Strabismus

Strabismus (strabismus, heterotropia) is an ailment characterized by unformed binocular vision of two eyes. This happens because one eye deviates to one side or another due to the weakness of the muscular apparatus.

Types (classification) of strabismus

Strabismus can cause a weakening of one or more extraocular muscles, subdivided into:

Converging (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 to the side temporal region heads;
Unilateral - only one eye deviates;
Alternate - there is an alternate deviation of both eyes.

Classification of strabismus according to the shape of the deviation of the eye

If the patient has binocular vision, but one or both eyes are deviated from the 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.

Latent strabismus

Strabismus of this kind can occur periodically, when the gaze is not fixed on any object.

Checked this species pathologies 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 movement of the object, then this indicates a latent 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 domestic and professional terms.

What is binocular vision? Binocular vision is the ability to clearly see an image with both eyes at once. Two images received by both eyes are formed into one three-dimensional image in the cerebral cortex of the head.

Binocular vision or stereoscopic vision allows you to see three-dimensional features, check the distance between objects. This type of vision is mandatory for many professions - drivers, pilots, sailors, hunters.

In addition to binocular vision, there is also monocular vision, this is vision with only one eye, the brain of the head selects only one picture for perception and blocks the second. This type of vision allows you to determine the parameters of an object - its shape, width and height, but does not provide information about the location of objects in space.

Although monocular vision gives good results in general, binocular vision has significant advantages - visual acuity, three-dimensional objects, and an excellent eye.

Mechanism and conditions

The main mechanism of binocular vision is the fusion reflex, that is, the ability to merge two images into one stereoscopic picture in the cerebral cortex. In order for the pictures to become one whole, the images received from both retinas must have equal formats - shape and size, in addition, they must fall on identical corresponding points of the retina.

Each point on the surface of one retina has its corresponding point on the retina of the other eye. Non-identical points are disparate or asymmetric regions. When the image hits the disparate points, the merging will not occur; on the contrary, a doubling of the picture will occur.

What are the conditions for normal binocular vision:

ability to fusion - bifoveal fusion;
consistency in the work of the oculomotor muscles, which makes it possible to ensure the parallel position of the eyeballs when looking far away and the corresponding convergence of the visual axes when looking near, joint work helps to obtain the correct eye movements in the direction of the object in question;
the location of the eyeballs in the same horizontal and frontal plane;
visual acuity of both organs of vision is not less than 0.3-0.4;
obtaining images equal in size on the retinas of both eyes;
transparency of the cornea, vitreous body, lens;
absence pathological changes retina, optic nerve and other parts of the organ of vision, as well as subcortical centers and the cerebral cortex.

How to determine

To determine the presence of binocular vision, use one or more of the following methods:

"Hole in the palm" or the Sokolov method - put a tube to the eye (you can use a folded sheet of paper) and look into the distance. Then put your hand on the side of the other eye. With normal binocular vision, a person will get the impression that there is a hole in the center of the palm, which allows you to see, but in fact the image is viewed through a tube.
Kalf method or miss test - take two knitting needles or 2 pencils, their ends must be sharp. Hold one needle vertically in front of you and the other in horizontal position. Then connect the knitting needles (pencils) with the ends. If you have binocular vision, you will easily cope with the task, if you have monocular vision, you will miss the connection.
Pencil reading test - while reading a book, place a pencil a few centimeters from the nose, which will cover part of the text. With binocular vision, you can still read it, since in the brain of the head there is an overlap of images from both eyes without changing the position of the head;
Four-point color test - the basis of such a test is the separation of the visual fields of the two eyes, which can be achieved using colored glasses - filters. Place two green, one red and one white objects in front of you. Put on green and red glasses. With binocular vision, you will see green and red objects, and white will turn green-red. In monocular vision, a white object will take on the color of the lens of the dominant eye.

Binocular vision can be developed at any age. However, this type of vision is not possible, since in this case one eye deviates to the side, which prevents the visual axes from converging.

How to check the presence and nature of binocular vision at home?

First, a violation of binocular vision can be suspected when, when you try to pour boiling water from a teapot into a cup, you pour it past the cup.

Secondly, a simple experiment will help to check the function of binocular vision. The index finger of the left hand must be placed vertically at the top at eye level at a distance of 30-50 cm from the face. index finger right hand you need to try to quickly hit the end of the left index finger, moving from top to bottom.

If this was done the first time, then we can hope that binocular vision is not impaired.

If a person has convergent or divergent strabismus, then, of course, there is no binocular vision.

Double vision is also a sign of impaired binocular vision, more precisely simultaneous, although the absence of such does not indicate the presence of binocular vision. Doubling occurs in two cases.

Firstly, in the case of paralytic strabismus caused by disorders in the nervous apparatus that controls the work of the oculomotor muscles. Secondly, if one eye is mechanically displaced from its usual position, this happens with neoplasms, with the development of a dystrophic process in the fatty pad of the orbit near the eye, or with an artificial (intentional) displacement of the eyeball with a finger through the eyelid.

The following experiment confirms the presence of binocular vision. the subject looks at a point in the distance. One eye is slightly pressed with a finger up through the lower eyelid. Next, observe what happens to the image. In the presence of full binocular vision, vertical doubling should appear at this moment. A single visual image splits into two, and one image goes up. After the cessation of pressure on the eye, a single visual image is restored again. If during the experiment doubling is not observed and nothing new happens to the image, then the nature of vision is monocular. In this case, the eye that was not displaced works. If doubling is not observed, but during the shift of the eye a single image shifts, then the nature of vision is also monocular, and the eye that was shifted works.

Let's put one more experiment (adjusting movement). The subject looks at a point in the distance. Let's try to cover one eye with the palm of our hand. If after that the fixed point shifts, the nature of vision is monocular and with two eyes open, the one that was covered works. If the fixed point disappears, then the nature of vision with the same eye is also monocular, and the eye that was not covered does not see at all.