Narrowing fields. Changes in the visual fields of the human eye. Scotoma

Visual field is a very important concept in ophthalmology, allowing one to assess the level of vision and diagnose many diseases. The field of view is understood as the size of the surrounding space when the gaze is directed strictly forward and fixed at one point. Due to peripheral vision a person can see surrounding objects, but more vaguely. Limitation of the field of vision and loss of certain areas indicate the presence of an eye pathology that requires urgent treatment.

Symptom Definition

Limitation and loss of the field of vision is characterized by a person in different ways. In some cases, the patient perceives the surrounding space as if through a translucent curtain. This may be caused by retinal detachment or nerve fiber damage. visual system . When the retina is detached, the shape of familiar objects is also distorted. And the area of loss may have a “floating” character.

A symptom similar to a surrounding foggy haze may indicate such a serious disease as. The patient also notices a rainbow halo on the lighting elements. In general, clouding of the vision zone in the form of a veil can indicate a number of diseases, and only an ophthalmologist, after carrying out the appropriate procedures, makes the correct diagnosis and prescribes treatment procedures.

Loss of visual fields is characterized by the disappearance of image elements in the center or periphery. In the first case, in the central part of the visible zone, the patient sees a dark area. If peripheral vision is impaired, the picture is perceived as if through a small hole. In the center, everything is visible very clearly and without distortion, and the peripheral areas completely disappear from the field of view.

Loss of visual fields can also be local in nature. In this case, small zones are formed in the field of view where there is no image. In ophthalmology they are called. They can be single or multiple. It happens that such a zone has been present in the eye for a long time, but due to its small size, the patient simply does not notice it. Only at an appointment with an ophthalmologist, after diagnostic procedures, does the patient learn that he has a serious illness.

Often a person does not notice that his field of vision has decreased. At the same time, the disease continues to progress. Only a visit to an ophthalmologist will allow you to determine the presence of pathology and begin treatment on time.

Causes

There are many reasons that can cause loss of visual fields. They can affect not only the organs of vision, but also be a consequence serious violations in the brain. The most common reasons causing disturbances fields of view:

cataract;
glaucoma;
pathology of the optic nerve;
eye injuries;
retinal detachment;
neuralgic diseases;
high pressure;
atherosclerosis;
diabetes.

Read what symptoms of cataracts exist. And also, to How to determine retinal detachment, read.

If some part of the image is seen as if through a translucent curtain, we may be talking about cataracts or growth of the conjunctiva (). IN initial stage Glaucoma affects the center of vision and only then does the pathology affect the peripheral areas. With severe pathology of the optic nerve, the eye completely ceases to see. Depending on the severity, eye injuries can lead to both loss of certain areas in the field of vision and severe limitation of peripheral vision.

When the retina is detached, the patient sees familiar objects in a distorted form. Proportions often change, and straight lines become curved. Sometimes the patient feels as if he is looking through a layer of water. In this case, the entire surrounding panorama is noticeably deformed. High blood pressure and atherosclerosis are very dangerous for the organs of vision. These diseases can cause blood clots to form in the blood vessels of the eye. In this case, some part of the retina stops functioning and the patient sees a dark spot in the field of vision or observes a narrowing of the visible zone.

This phenomenon occurs spontaneously and disappears after some time as the blood clot self-destructs. Loss of visual fields may be systematic. Small blood clots block the blood supply to the retina and for a certain time, the affected area stops sending signals to the brain. Then the blood supply is restored and the patient begins to see well again.

Even if the loss of the visual field was short-term and did not recur, you should definitely visit an ophthalmologist.

Possible diseases

Often the cause of visual field impairment is diseases that are not directly related to the structure eyeball. These can be severe damage to the brain or nerve fibers. Loss of half of the visual field structure can be caused by the following diseases:

meningitis;
aneurysm carotid artery;
brain tumor;
encephalitis;
pituitary adenoma.

With meningitis, the patient experiences severe headaches. Corneal problems also occur against the background of multiple loss of visual fields. A carotid aneurysm causes severe vision loss, which can result in complete blindness. Brain tumors can cause severe pronounced violations fields of view. Pituitary adenoma is characterized by loss of the visual field on the temporal side, and red scotomas may appear in the central visual field. With the further development of this disease, outlier zones appear across the entire visible spectrum. Disruption of the blood supply to the center of vision located in the brain causes a concentric narrowing of the visible fields.

Regular headaches accompanied by blurred vision may be the result of severe brain damage. If such symptoms appear, you need to go full examination.

Diagnostic methods

Diagnosis is based on patient complaints and perimetry. When visiting an ophthalmologist, it is necessary to describe as accurately as possible all the negative manifestations that diagnostic equipment cannot detect. Such manifestations include:

headache;
feeling of pressure on the eyeballs;
dizziness;
imbalance;
light sparks in the field of view.

If you have floaters before your eyes, then read.

Carrying out perimetry

All these symptoms will help the doctor make an accurate diagnosis, and, if necessary, prescribe additional consultations with a neurologist and neurosurgeon . To determine the impairment of visual fields, loss of individual zones and precise localization of areas, the Perimeter ophthalmological device is used. The device has several modifications, but computer perimetry is considered the most accurate diagnostic method. Since the human eye does not respond equally to the colors of the spectrum, visual field loss testing is usually performed for all primary colors.

Diagnosis of visual field loss is a non-contact method that takes no more than 30 minutes. During this procedure, there is no effect on the eye.

Treatment

Loss of visual fields is a consequence of any disease, so eliminating this pathology begins with treating the underlying cause. In some cases, the disease is treated with medication, but in severe cases, surgery must be used. A common cause of visual field impairment is retinal detachment. In this case, surgery is required or laser coagulation, with which the detached part is welded into place using a laser.

For glaucoma, the patient is prescribed medications to reduce the pressure inside the eye. In some cases, the patient can only be helped surgery. At nervous diseases or brain damage diagnostic procedures and treatment is carried out by doctors of appropriate specialization. Sometimes the patient may need to consult an oncologist.

When scheduling an operation, you should strictly follow all the doctor’s instructions. This is especially true for the postoperative period.

Prevention

As preventive measures To reduce the risk of eye diseases, it is recommended to adhere to a work-rest schedule. This is especially true for those who constantly work on a computer and those who work in hazardous industries. People with high blood pressure and diabetics need to constantly monitor their negative parameters.

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conclusions

The emergence and development of eye diseases is largely provoked by the victims themselves. Many people believe that visiting a doctor is necessary for those who are sick, but a healthy person does not need it. This is a big mistake. Only an ophthalmologist can determine eye disease by early stage when there are no objective symptoms that can be felt yet. A timely visit to the eye office can save you from many problems in the future.

Also read about what chorioretinitis of the eye is and about heterochromia.

Visual fields in ophthalmology are an important concept in the diagnosis of various diseases. Based on the nature of these changes, differentiation is made various pathologies, associated not only with the organ of vision, but also with the central nervous system.

The field of view is the coverage of the amount of space with a strictly fixed gaze forward. Changes in visual fields are a symptom indicating the presence of a particular disease.

Loss of visual fields or their narrowing is the main pathological symptom in ophthalmology. Each patient with a disease accompanied by changes in visual fields gives his own specific description of sensations. Most accurate this pathology detected only with the help of hardware diagnostics in an ophthalmology office.

Hemianopsia is a condition when half of the visual fields are lost, both unilateral and multilateral. The patient experiences blindness in one half of the visual image. The border between the visible and invisible halves of this picture is the central line running from top to bottom. Such loss of visual fields speaks in favor of pathology from the central nervous system, and not from ophthalmology. This pathology can be either temporary or permanent. It all depends on the degree of damage to certain parts of the brain.

With hemianopsia, half of the visual field is lost

According to the classification, hemianopia is divided into the following types:

homonymous;
heteronymous;
bitemporal;
binasal.

Homonymous

This terminology means that this is a pathological process in which the patient sees only one half (right or left) of the visual image. The cause of the development of this type of hemianopsia may be a lesion in a certain location of the optic tract or in the cortex occipital lobe brain.

According to the classification, homonymous hemianopsia is divided into the following types according to loss of visual fields:

complete - the field of view completely disappears in the visual picture on the right or left;
partial – loss of a narrower section of the visual field occurs. Can develop on both the right and left;
quadrant – the field of view is lost in the upper or lower quadrant;
scotomas are a dark area in the field of view of a round or oval shape, located on the right or left, which can be either absolute or relative. With absolute scotomas, in its area, vision is completely lost, and with relative scotomas - partially.

Causes of hemianopia

Homonymous hemianopsia can be either congenital or acquired. Most common reasons loss of visual fields:

vascular lesions of the brain in the form of ischemic or hemorrhagic strokes;
brain injuries;
brain tumors with a benign or malignant course;
transient or transient cerebrovascular accidents;
hysterical reactions;
hydrocephalus;
migraine;
epileptic seizures.

Homonymous hemianopia can be transient in nature with transient vascular disorders, migraine, and epileptic seizure. The nature of this transient pathology of visual field loss is explained by short-term swelling of a certain area of the brain. If the swelling of this area of the central nervous system subsides, pathological blindness regresses and visual functions are restored.

The development of such a symptom in neurological diseases, like hemianopsia, allows for topical diagnosis and a clear determination of the location of the brain lesion.

Brain lesions may result in loss of visual fields

Heteronymous

This type pathology is characterized by loss of nasal or temporal visual fields. The boundary between the visible and lost parts of these fields runs horizontally. This hemianopsia, like homonymous hemianopsia, is divided according to the nature of the loss of visual fields into complete, partial, quadrant and scotoma.

Bitemporal

The most common type of pathology, manifested in the loss of the temporal halves of the visual fields in both eyes synchronously. This pathology can develop with basal arachnoiditis and aortic aneurysm. Brain damage is observed in the area of the pituitary gland and optic chiasm.

Binasal

With this type of pathology, the nasal half of the visual fields on both sides are lost. This type of hemianopsia rarely develops and is diagnosed with chiasmatic arachnoiditis, developing hydrocephalus, and with a tumor process of the brain.

Diagnostics

Diagnosis of hemianopsia is carried out taking into account the study of visual fields using computer perimetry and fundus readings. Availability clinical symptoms the disease is confirmed by additional laboratory tests. Especially if you suspect volumetric process pituitary gland Typically, symptoms of hemianopsia indicate serious brain damage. To clarify the diagnosis, computed tomography, MRI, and skull radiography are performed.

Perimetry allows you to determine the type of visual field loss

Methods of treatment and prevention

Treatment of hemianopsia is aimed at eliminating the underlying cause of the disease. The sooner measures to eliminate the underlying disease are started, the more favorable the prognosis for the patient may be. later life. As a rule, neurological diseases leave behind persistent organic changes in the central nervous system.

Previous cerebrovascular accidents, head injuries, surgical removal brain tumors require long-term rehabilitation of the residual effects of these diseases. Rehabilitation of patients with hemianopia should be carried out not only medications. Such patients need adaptation to navigate the outside world. This can be helped by wearing special glasses with certain mirrors, classes using specially developed computer programs aimed at improving vision.

The prognosis for the future life of patients with hemianopsia is unfavorable. Basically this pathology organic character remains, there is no regression of symptoms.

A positive prognosis is noted only in cases where the patient after a stroke suffered in the form of transient disorder cerebral circulation, comes out of a painful state without consequences. The symptoms of the disorder regress along with the symptoms of hemianopsia. The same reverse development of symptoms is observed with migraines, epileptic seizures, and hysterical reactions of the body. In all these cases, there is a positive trend in the disease and a positive prognosis for the future.

The field of view is the entire space simultaneously perceived by the fixed eye. In other words, the field of view is the space projected onto a plane, visible with a motionless, fixed eye.

Boundaries of the field of view:

The anatomical boundaries are determined by the position of the eyes in the orbit, the depth of the anterior chamber, the width of the pupil, and the type of facial skull.

2. Physiological boundaries depend on the state of the visual-nervous apparatus of the eye and visual centers.

The central part of the visual field (formed by the blind spot and the vascular bundle). Physiological scotoma (blind spot, Bjerrum's scotoma) corresponds to the projection onto the plane of the optic nerve, which does not have light-perceiving receptors. Physiological scotoma is not subjectively perceived due to the partial overlap of the visual fields of both eyes and the movement of the eyeballs.

Angioscotomas are ribbon-shaped (crescent-shaped) loss of the visual field, which is a projection onto the plane vascular bundle or individual vessels.

The size and shape of the blind spot and angioscotomas can vary with different local and general pathologies. Pathological central scotomas are observed when the retina is damaged in the area of the macula or papillomacular bundle (it consists of nerve fibers coming from retinal ganglion cells).

Peripheral part of the visual field. The outer boundaries of the visual field in adults are on average 60° on the nasal (medial) side, 90° on the temporal (lateral) side, 50° on the posterior (upper) side, and 70 on the maxillary (lower) side. °. In children preschool age the boundaries of the visual field are approximately 10% narrower than in adults (Fig. 4).

Types of changes in peripheral vision with various diseases: concentric narrowing, sectoral, local, half (hemianopsia) loss, etc. The field of view for chromatic colors is much narrower than for white. The extreme periphery, where there are no cones, perceives only white color; closer to the center, blue, yellow, red and green colors begin to be perceived. Narrowing of the field of view to blue and yellow colors more often caused by pathology of the choroid, and in red and green - by pathology of the conduction pathways.

Rice. 4. Boundaries of the peripheral part of the visual field (for white color)

We will talk about what narrowing the field of view is. The area that a person covers with his vision in a state of immobility of the pupil and head is the field of vision. It is divided into a central and peripheral field. When the pupils shift towards the bridge of the nose, as well as when the eyes are deeply planted, the field of vision decreases and narrows, and when the eyeball protrudes more forward, on the contrary, it increases. This phenomenon is called artificial limitation of the field of view.

Causes

Some diseases lead to a narrowing of the visual field, in which the patient loses, to some extent, peripheral or central visibility. There are two types of this symptom and reasons for the narrowing of the visual field:

concentric narrowing, characterized by the global extent of the lesion;
local narrowing that occurs in a specific area.

Concentric narrowing

Concentric narrowing of the visual field may be insignificant, or it may have a pronounced form. In severe cases, patients experience so-called “tube” vision. With this symptom, the objects that the patient sees are evenly distributed in the area covered by vision. The concentric form of narrowing of the visual field is often provoked by a disease of the nervous system, such as neuroses, hysteria and neurasthenia. It can also be caused by diseases of the human visual system, for example, optic nerve atrophy, neuritis and others.

As for local narrowing of visual fields, it also has its own types; it can be either unilateral or bilateral. Bilateral can be detected by symmetric and asymmetric lesions of areas.

To determine the type of vision limitation, medical specialists They conduct special tests, for example, they find out how the patient sees the same objects at different distances. If the patient has a concentric type of narrowing, then the size and distance of the objects he is looking at will not matter. And poor orientation in space indicates that the patient has a local type of narrowing of the visual fields.

This symptom is typical for neurological diseases and eye diseases. For example, with glaucoma, patients complain of a gradual limitation of the visual field, which begins from the nasal part and moves to the central part. Unfortunately, it is very rarely possible to restore vision in this disease, since the narrowing is detected even with a very advanced disease, and patients often present late. Patients with glaucoma very often suffer blindness as a result.

It is important to know that chronic open-angle glaucoma provokes increased intraocular pressure and thus leads to dysfunction and atrophy of the nerve, as a result of which the visual field gradually narrows and the patient becomes completely blind.

Cases of limited vision are also common among neurological diseases. And the reason for this is a pituitary adenoma, since this organ, with this disease, greatly enlarges and puts pressure on the visual organs located underneath it.

If there is even a slight narrowing of the field of vision, it is necessary to urgently contact an ophthalmologist and neurologist - this could be the beginning of a serious illness.

If there is a refractive error (farsightedness, nearsightedness, astigmatism), a person experiences serious discomfort. However, these conditions can be corrected quite well. Much worse is complete blindness, which often becomes irreversible. In this regard, it is necessary to be very careful about any changes in vision that may signal the onset of the disease.

In the human body, all systems and organs are interconnected and any deviations can be noticed by an attentive patient. Small changes often warn a person of much more significant deviations. One of these changes in the operation of the optical system is a violation of the visual field. This issue is discussed in more detail below.

Concept of field of view

The field of view is the entire space that the eye perceives. The field of view can be determined by fixing the gaze and keeping the eyes and head stationary. In this case, the subject clearly perceives only the central zone, and objects in the peripheral zone will be perceived as more vague.

Loss of visual fields

Normally, a person can perceive the fingers of a hand that is moved to the side by 85 degrees. If this angle is smaller, then the patient experiences a narrowing of the field of vision.

If the subject can perceive only half of the space, then there is a loss of half of the visual field. This symptom often accompanies serious diseases of the central nervous system, including the brain.

In order to more accurately diagnose the pathology in a patient with loss of visual fields, it is necessary to consult a doctor. Various techniques are used to examine these patients.

When half of the visual fields or even quarters are lost, we are talking about hemianopsia. Usually this pathology is bilateral, that is, the visual field is damaged on both sides.

Sometimes the loss of visual fields is concentric in nature. In this case, the condition may worsen to the point of tube vision. A similar symptom occurs with optic nerve atrophy or severe glaucoma. Sometimes this narrowing of the visual field is temporary and is associated with psychopathy.

With focal loss of the visual field, we are talking about a scotoma, which is characterized by the appearance of shadows or islands of absent or decreased vision. In some cases, scotoma can be detected only during a special examination of the patient, that is, he himself does not notice the visual impairment.

If the scotoma is located in the central zone, then most likely it is associated with macular degeneration and age-related changes in the area of the macula.
Due to the fact that very effective methods of treating these serious diseases have recently appeared, you should follow all the instructions of your doctor.

Reasons for violations

Depending on the cause of visual field loss, the nature of the pathology may be different. Usually there is a malfunction of the receiving apparatus of the optical system. If the pathology manifests itself as a so-called curtain on one side, then most likely the cause of the disease lies in disruption of the conduction pathways or retinal detachment. In the latter case, the disturbance of the visual field is accompanied by distortion of the shape of objects and a break in straight lines. The size of the visual field defect may also differ between the morning and evening hours. In some cases, the patient perceives surrounding objects in the form of floating figures. Retinal detachment often develops against the background of severe myopia, traumatic injury to the eye, or degeneration of the cells of this layer.

If there is bilateral loss of visual fields from the side of the temples, then we are probably talking about a pituitary adenoma.

If the field of vision is disturbed in the form of a translucent or dense curtain, which is located on the nasal side, then this indicates high intraocular pressure. Also, with glaucoma, rainbow circles appear when looking at point sources of light or fog in front of the eyes.

A translucent curtain on one side may appear when the transparency of the optical media of the eye decreases. These include cataract, cataract, pterygium, vitreous opacification.

When the central part of the visual field is lost, the cause of the disease is most often caused by a malnutrition of this area due to macular degeneration or pathology of the optic nerve and its atrophy. With macular degeneration, there is also a violation of the perception of the shape of objects, uneven changes in image size, and curvature of lines.

With concentric (up to tubular) narrowing of the visual field, we are usually talking about pigmentary degeneration of the retinal substance. At the same time, central visual acuity remains normal for quite a long time. Also, a concentric narrowing of the visual field is observed in glaucoma, but in this case the acuity of central vision is also reduced.

Typically, a concentric narrowing of the visual field is manifested by the fact that a person spends a very long time looking for the keyhole in the door, cannot navigate in an unfamiliar environment, etc.

With sclerotic changes in the arteries of the brain, the nutrition of nerve cells in the cortical visual centers is disrupted. This condition can also cause a concentric narrowing of the visual field, but the acuity of central vision also decreases, and there are other symptoms of brain malnutrition (forgetfulness, dizziness).

How is the verification done?

To determine whether a patient has visual field defects, a complete examination is necessary. In this case, the doctor will be able to determine the area of the lesion, as well as the level of change in the structure of the optical system. This will help establish the diagnosis of the disease or lead to the need to conduct a number of additional examinations.

To evaluate visual fields, you can use one of the generally accepted techniques.

An experiment that is easy to carry out will allow you to approximately assess the state of your vision. In this case, you need to look into the distance and extend your arms to the sides (at shoulder level). After this you need to move your fingers. With normal peripheral vision, a person can easily notice the movement of the fingers. If the patient cannot notice the movement of the fingers, then he has lost peripheral vision.

Some people believe that only central vision is important, but this is not true. For example, in the absence of peripheral vision, it is impossible to navigate in space, drive a car, etc.

The quality of vision can be affected by various diseases, including glaucoma. In this case, the field of view gradually decreases, that is, its concentric narrowing. This symptom is a reason to immediately seek medical help.

When carrying out diagnostic manipulations, the doctor can accurately determine the localization of damage in the optical system (before or after the optic chiasm, directly in the chiasm zone).

If the ophthalmologist identified a scotoma on only one side, then the damage is located up to the chiasm, that is, it affects either the retinal receptors or the optic nerve fibers.

Visual disorders can be present independently or combined with other pathologies of the central structures of the nervous system, which include disorders of consciousness, motor activity, speech, etc. Sometimes they are a consequence of impaired blood flow in the arteries that supply blood to the visual centers of the brain. Most often, young or middle-aged patients are susceptible to this condition.

With vegetative-vascular disorders, the first thing that appears is loss of the visual field. After a few minutes, these defects move left and right. They can also be felt when the eyelids are closed. This leads to a significant decrease in visual acuity, and then to severe headaches.

You can help a patient in this condition if you let him rest in his own bed, after unbuttoning the tight clothes. In addition, you can use receptor drugs, for example, give the patient a validol tablet to dissolve. If this condition recurs, then in addition to the ophthalmologist, you should definitely visit a neurologist.

To assess the patient's condition, you need to use special computerized installations. In them, against a dark background, light points flash unevenly, which can have the same or different brightness and size. After this, the installation registers those areas that did not fall into the field of view.

Changes in field of view

Visual field impairment can be associated with various pathologies. All these changes can be divided into two large groups:

Focal visual field defects, or scotomas.
Concentric narrowing of the boundaries of the visual field.

At the same time, for everyone specific disease The appearance of certain defects in the visual field is characteristic. The doctor uses these symptoms for topical diagnosis of diseases of the central nervous system.

Focal defects (scotomas)

If vision is reduced or absent in a certain area, the boundaries of which are not adjacent to the outer contour of the visual field, then we are talking about a scotoma. In this case, visual defects may not be perceived by the patient, because the image is completed by the second eye. Such scotomas are called negative. With positive scotomas, the patient perceives the defect as a spot or shadow located in the field of view.

The shape of scotomas can be different (sector, arc, oval, circle, irregular polygon). Depending on the location of scotomas relative to the central point of fixation, they also have different names (peripheral, sectoral, pericentral, paracentral, central). If vision is completely absent in the defect area, then the scotoma is called absolute, otherwise - relative (only the clarity of perception is impaired).

An interesting fact is that in one patient the scotoma can be both relative and absolute (when examining the visual field using markers of different colors).

In addition to various pathological scotomas, each patient also has so-called physiological scotomas. These include the blind spot and vascular pattern.

In the first case, we are talking about an oval-shaped absolute scotoma, which is located in the temporal zone of the visual field. This scotoma corresponds to the projection of the optic nerve head. There is no light-receiving apparatus in the blind spot area.
A physiological scotoma has clear dimensions and location. If a change in these parameters occurs, for example, an increase in size, then the scotoma becomes pathological. In particular, an increase in the size of the blind spot is observed with papilledema, glaucoma, and hypertension.

To identify scotomas, doctors previously resorted to rather labor-intensive visual field studies. Recently, mainly automatic perimeters are used, as well as testers for central vision, which greatly simplifies the procedure and reduces its execution time to several minutes.

Changing the boundaries of the field of view

The narrowing of the boundaries of the visual field can be concentric, that is, global, or local. In the latter case, the formation of a defect occurs in a certain area, while on the rest of the perimeter the boundaries of the visual field are not broken.

Concentric narrowing

With concentric narrowing, much depends on the degree of this process. Thus, in severe cases, so-called tube vision is formed, in which peripheral perception is almost completely lost.

Concentric narrowing of vision can be associated with various pathologies, including neuroses, neurasthenia, and hysteria. In such conditions of the nervous system, the narrowing of the visual field is functional in nature.

However, concentric narrowing of the visual field is more often associated with organic pathology, for example, peripheral chorioretinitis, atrophy or neuritis of the optic nerve fibers, retinitis pigmentosa, glaucoma.

To accurately determine the nature of the narrowing of the visual field (functional or organic), it is necessary to conduct a series of studies. They use objects of different sizes, colors, and brightness. In case of functional deviations, the size of the object and its other characteristics do not affect the result of the study. In addition, the patient’s ability to navigate in space is used as a distinguishing feature. If this property is violated, then most likely we are talking about an organic lesion.

With local narrowing of the visual field, the process can be bilateral or unilateral. With bilateral lesions, the defects can be located symmetrically or in different areas of the visual field.

In this case, some characteristic areas of vision loss, for example, hemianopia (half loss of visual fields), are of important diagnostic importance. In this condition, we are talking about damage to the visual pathway in the chiasm zone or closer to the central structures.

Hemianopsia can be diagnosed independently, but more often such visual impairments are identified during examination of the patient.

Hemianopsia can be homonymous (loss of the temporal half on one side and the nasal half on the other) or heteronymous (simultaneous loss of the nasal or temporal halves on both sides). There is also quadrant hemianopsia, when the beginning of the defect coincides with the fixation point.

Hemianopsia

Homonymous hemianopsia most often occurs as a result of pathological space-occupying formations in the brain (tumor, abscess, hematoma) or with retrochiasmal lesions visual pathway(opposite side). In such patients, hemianoptic scotomas may be detected, which are located in symmetrical areas of the visual field.

In heteronymous hemianopsia, the defects can be located on the outer side (bitemporal hemianopsia) or on the inner side (binasal hemianopsia). In the first case, the visual pathway in the chiasm zone is affected, which is characteristic of a tumor process in the pituitary tissue. With binasal hemianopsia, there is damage to the uncrossed fibers of the optic pathway in the chiasm zone. This can occur when the internal carotid artery aneurysm puts pressure on the external nerve fibers in the decussation area.

Where to treat?

Treatment for visual field defects depends on the cause of the disease. In this regard, it is very important to carry out quick and high-quality diagnostics using modern equipment. The data obtained will help the doctor prescribe the correct treatment, otherwise the patient's condition may worsen.

The retina of our eye perceives visual signals unevenly. A person's field of clear vision in each eye can range from 60 to 90 degrees. Accordingly, the total is about 120 degrees. And a person can clearly distinguish colored objects within a narrower range. And on the periphery, monochrome images and sudden movements are more susceptible to perception. Accordingly, sometimes it happens that peripheral vision becomes worse.

Thus the field of view narrows. And the person already sees a smaller picture. For example, he may not notice a person who is about to cross the road from the side. But it happens when the field of vision narrows even more. And in this case, a person clearly sees only what is directly in front of him. And everything that he is already at least a few meters to the side, he perceives very blurry. This is the insidiousness of glaucoma - a serious eye disease.

Can a person not notice vision problems?

Yes it is possible. There are gas diseases that are asymptomatic. And it affects only one eye at first. This disease is called glaucoma. And the problem is that not at the beginning of the disease, but as it develops, only one eye is affected. And only a segment of the eye that, unnoticed by the patient, ceases to function. The second eye sees well and partially takes over the function of the affected one. The patient does not notice and does not know that he is sick for a long time.

Symptoms of glaucoma of the eye

It is not easy to suspect glaucoma. The fact is that long time the patient notices things that he does not consider to be a disease.

Adaptation disorders at dusk.

Impaired vision for near and far distances.

Impaired peripheral vision, when he suddenly accidentally notes that he did not notice some object. Who stood on the side. In everyday life, this seems like just an episode. But in fact, this is a rather serious symptom of this formidable disease.

How to detect glaucoma at home

The simplest thing that can be suggested to everyone is to periodically close one eye and see how he sees with it. Then we do this with the other eye. We evaluate the visual range of each eye.

In ancient times, peripheral vision was tested in this way. They took a candle, closed one eye and pointed a light source to mark the area that the eye sees. Now technology has moved far from this method. However, this is a fairly simple and understandable method for everyone. It can allow you to at least suspect the presence of a disease such as glaucoma.

How can a person independently carry out such a check at home?

Method No. 1. You sit down in front of the mirror. Close one eye. Take a flashlight or candle. Then move it at arm's length towards the center. Move slowly so that you mark the moment when you see it. Because if you do not have any pathology, you are already in the position of the arm parallel to the shoulder, you will see the light. The same thing needs to be done with inside. The simplest thing is to repeat this action either from below or from above. We don’t know the norms, but at least if we see the difference between how light appeared when checking one eye and the other, this is already serious reason go to an ophthalmologist.

Method No. 2. There is also another one simple circuit. We close one eye and evaluate the quality of vision of the other, then do the opposite. Because our vision is binocular, our eyes layer the image and we do not notice the pathology of one of them.

Conclusion. To detect glaucoma early, see an ophthalmologist annually after age 40. But on extreme case do the tests at home that we wrote about in this article.

When a person looks straight ahead, he still catches what is happening to the side. This is colloquially known as "catch it out of the corner of your eye." The scientific name is peripheral vision. It is present in all vertebrates without exception, and is an important aspect of vision. It is also called “side”.

In the literature you can often find the concept of “peripheral vision”. Disputes arise: what kind of vision do we have, peripheral or peripheral? That's right, both ways. These are different names for the same phenomenon.

Peripheral vision perceives white light best, and then, in descending order, all the colors of the spectrum, starting from red. it also weakly perceives the shape of objects, but is sensitive to movement and flickering of objects. And the faster this flickering, the better the eye will perceive it.

There is also central vision - all objects fall into it when we look directly ahead. This means that most of what we see falls into the “zone of responsibility” of the peripheral. And how much we see depends on our field of vision. So when checked by an ophthalmologist, a peripheral vision test will definitely be carried out.

When we look forward in a relaxed state, in addition to the objects located there, we also notice what is on the sides. Everything that thus captures the eye is the visual field. The higher a person’s visual acuity, the further he sees, but lateral vision practically does not depend on this.

By “field of view” we mean not only what a person sees horizontally, but also vertically.

Examination of the state of this vision is very important in diagnosing diseases of the retina, optic nerves and visual acuity. In case of retinal diseases, the doctor examines the patient’s field of vision dynamically over a long period of time. And it is the state of peripheral vision that can indicate the characteristics of the pathological process in the eye and help select effective treatment.

To a certain extent, the field of vision is narrowed due to the protruding parts of the face - nose, cheekbones, eyebrows. If a person wears glasses, then their frame may somewhat limit the view.

Visual field examination - main way diagnostics of peripheral vision. And the simplest of all is the control method. It does not require any instruments; the doctor, with a healthy and complete field of view, compares that of the subject with his own.

For a more accurate determination, computer diagnostics are performed - the patient looks into the eyepieces, the doctor demonstrates various objects that appear on the sides and approach the middle of the view. As soon as the patient notices them, he presses the button, and the computer records it.

Peripheral vision examination is carried out on each eye separately.

Why do we need peripheral vision?

All vertebrates and birds have this type of vision. Only in different types of living organisms it covers a different radius. For a person with healthy vision, this angle is 120 degrees in each eye. vertically and horizontally. In some eye diseases, this angle narrows. Peripheral vision can also deteriorate in the event of injury to the eye itself - a concussion, burn, bruise, or overstrain of the eye itself.

Narrowing of peripheral vision can also be a consequence of brain diseases.

Structure of the retina: rods and cones

The human eye is a complex optical instrument. It perceives, analyzes and transmits information to the retina, giving an idea of color, distance, etc. At different times of the day they are responsible for all this various areas retina, its various receptors. These receptors transform light stimulation into nervous stimulation. In other words, light is converted into electrical impulses, and the optic nerve transmits them to the brain. Due to the similarity of shape, they were called

rods - those that are responsible for perception in the dark
cones - responsible for visual acuity and color perception

And it is the rods that are most involved in the work of peripheral vision.

In the eye of a healthy person there are about 120 million rods, and only 7 million cones.

Rods are very photosensitive, they only need 1 photon of light to react, but they cannot distinguish the color of an object. Since there are disproportionately more rods, they are located mainly “on the periphery” of the retina, while cones are located mainly in its center. Thanks to the large number of rods on the periphery of the eye, a person notices the objects surrounding him in the dark.

Peripheral vision works well in the dark, when color perception is not relevant, so it is black and white. The fact that we perceive colors with peripheral vision during daylight hours is due to the work of the cones.

Functions

We need it to better navigate space. It is carried out mostly by the rod apparatus, so this is also... Thanks to it, we can move in the dark, distinguish objects even in almost complete darkness, because the rods react to the smallest light emissions.

In herbivorous mammals, the eyes are always located on the sides, and their viewing angle is almost a full circle. But their central vision is not very good, its acuity is quite low.

Development of peripheral vision

The eyes of a human embryo begin to develop in the first month after conception; it is such a complex organ and it takes so much time to form. At the same time, the retina, rods and cones are formed.

In a newborn baby, it is very poorly developed; the baby practically does not use it. At this time it is limited only to reacting to light. The child may turn his head towards the source, but not yet follow with his eyes.

As the child ages, visual function increases; by the age of three, the child no longer needs to turn his head to the image that interests him, and by the age of 6, peripheral vision is almost completely formed. Now it is only developing and strengthening - until puberty. The point of view of a teenager is no longer different from that of an adult.

However, already formed peripheral vision can be improved and strengthened. This is facilitated by special exercises for developing breadth of vision.

In order not to confuse which retinal receptors are responsible for what, you can remember - during the day scientists work with cones, at night, in order not to fall, they use a rod.

Why develop

Lateral vision arose in humans back in prehistoric times, when danger lurked at every step and it was necessary to identify it in time.

Peripheral vision is physiologically weaker than central vision; it tends to narrow with age. But it can be developed with the help of several fairly simple exercises.

It would be quite reasonable to ask the question: why develop it?

The fact of the matter is that it is necessary; in many cases, well-developed peripheral vision can save lives.

Situations on the road. The most common situation in the city is a person crossing the road, and a car appears around a bend at high speed. With peripheral vision, a person notices it and manages to react and stop. It’s the same with drivers - you need to change lanes into the next lane, but another car appears, which it’s better to let through. With their peripheral vision they managed to catch it and assess the situation. And just walking along the road to see other road users.

In sports. In group sports, this vision helps to notice what is happening nearby, interact better with the team, and see the opponent. During martial arts matches, athletes also detect any movements of the opponent.

Speed reading. The main principle of speed reading is the ability to “capture” large volumes of text while expanding the angle of view. In this way, the skill of “diagonal reading” is trained.

And in many life situations it is impossible to do without peripheral vision.

Peripheral vision impairment

Peripheral vision impairments are quite often temporary, for example, the field of vision narrows during severe alcohol intoxication. It is restored when the person returns to normal.

With severe blood loss, injuries, shock, stress, nitrogen poisoning - all this leads to short-term impairment of peripheral vision.

There is organic damage to the retina, when the problem is practically insoluble, and the course of the disease can only be slowed down, it cannot be cured, for example, as with glaucoma.

There is a lack of peripheral vision when there is only central vision. In this case, a person sees all objects as if through a pipe. This is called a violation. If this condition is caused by glaucoma or retinal degeneration, treatment may be prescribed. The same condition often occurs in people in extreme situations, when there is overload of the optic nerve - in astronauts, military pilots, divers, climbers at high altitudes, and in other cases oxygen starvation. But in this case, tunnel vision does not last long and the eyes quickly return to normal without treatment. They just need to give it a rest.
The opposite also happens - peripheral vision is present, but central vision is not. This condition is called central scotoma. There are several types of them, often scotoma is caused by depression of the cerebral cortex. Then a person in the central part of the eye sees a flicker, while in the periphery the image is clear.

In both cases, vision functions are impaired.

Ischemic optic neuropathy

This is damage to the optic nerve that occurs when there is a sudden deterioration in its blood supply. Then the field of vision and visual acuity suddenly and sharply narrow, and peripheral vision suffers. Mostly men over 40 years of age are susceptible to it, and it is not an independent eye disease - it is concomitant with other systemic diseases. This is a very serious condition that, if left untreated, most often leads to complete irreversible blindness.

Most often, the attack occurs in only one eye, but a third of patients also have bilateral disorders. Usually the second eye is attacked after a few days, but it happens that it takes from two to five years. The attack develops suddenly and rapidly - after sleep, physical stress, sauna, hot bath, stress. Immediately, vision deterioration occurs, down to tenths. There may be a complete loss of light perception, total blindness. Moreover, the disease can develop within a few minutes, so when visiting a doctor, the patient will indicate the time of the onset of the attack with an accuracy of a few minutes.
So-called precursor symptoms often occur - short-term blurred vision, pain “behind the eye,” severe headaches. If such signs occur, you should not delay consulting a doctor.

At the first symptoms, treatment for peripheral neuropathy is immediately started - decongestants, anticoagulants, vitamins are immediately prescribed, thrombolytic, antispasmodic therapy, magnetic therapy, electrical and laser stimulation of the optic nerve are performed.

The prognosis is most often unfavorable, as rapid atrophy of the optic nerve occurs. In rare cases, it is possible to increase vision by 0.1 unit.

To prevent this disease, general vascular therapy and treatment of other systemic diseases of the body are carried out. Patients who have had this disease in one eye are registered with an ophthalmologist, they are under lifelong dispensary registration, and they are prescribed appropriate preventive therapy.

Exercises to develop peripheral vision

The good thing about these exercises is that many of them can be performed without attracting anyone's attention, even while walking down the street or sitting in public transport. For others, you will need a quiet environment, a little more space. But in any case, doing them will not require a lot of your time, and you can learn how to do them correctly in one day. What these exercises have in common is that they must be performed without tension, in a relaxed state.

Focus on one point in front of you. Try not to move your pupils. At the same time, record everything that you see around you, outside the field of direct vision - on the sides, above, below. First, do this exercise sitting and at home; after some time, you can practice it in nature. It doesn’t matter if some objects move, for example, an airplane.
Pick up pencils. Look straight ahead. Move your arms forward, begin to spread them to the sides until you can no longer see them. At first it will be a very short distance, then the angle of view will increase significantly. In the future, move your hands with pencils in different planes, it is only important not to move your pupils.
Draw a square with numbers from 1 to 9 on a piece of A3 paper, and put a large dot in the center. Read the numbers by looking only at the dot. In the future, the numbers can be made smaller and their number increased.

The field of view is the space that the human eye can capture when stationary. Visual field impairment is a symptom that cannot be ignored, because it can indicate both eye disorders and the presence of brain pathologies. In this case, a violation of the visual field can be local (blocking visibility in certain parts of the visual field) and global (when the picture that the eye perceives becomes narrower as a whole).

Visual field impairment: concentric and local narrowing

A violation of the visual field, manifested in a narrowing of its boundaries, is called concentric. If the field of view narrows in a certain area, while the remaining boundaries remain unchanged, a narrowing of a local nature occurs.

The degree of impairment of the visual field can vary: from deterioration of visibility to a more pronounced narrowing, in which a person seems to be looking through a pipe.

Concentric narrowing of the visual field can occur as a result of disorders of the nervous system (neurasthenia, neurosis, etc.), or can be caused by damage to the visual organs (optic atrophy, glaucoma, etc.).

Visual field disturbances can occur in one or both eyes and can be symmetrical or asymmetrical.

Scotoma – focal impairment of the visual field

A visual field impairment that manifests itself in a limited area, the boundaries of which do not coincide with the peripheral boundaries of the visual field, is called a scotoma. Simply put, scotomas are spots that appear in any part of the visual field.

The shapes of scotomas can be different, and the visual field impairment can be relative (when there is a decrease in image clarity within the scotoma) or absolute (a complete absence of image in a certain area of the visual field). Also, scotomas can be color scotomas - when a person cannot see or distinguish certain colors, and flickering scotomas (occur due to stress, physical and mental stress, circulatory disorders in the area of the optic nerve, and certain brain pathologies).

Main causes and treatment of visual field disorders

The causes of visual field impairment may vary. For example, scotomas or narrowing of the visual field (including tunnel vision) can be caused by:

cataracts;
glaucoma;
retinitis;
eye injuries;
optic nerve injuries;
retinitis;
dystrophic processes;
retinal detachment;
optic nerve atrophy;
brain tumors;
sudden drop in blood pressure;
nitrogen poisoning;
oxygen starvation;
loss of blood;
hallucinogens;
neurological diseases;
atherosclerosis;
hypertension;
diabetes mellitus;
retinal pigmentary degeneration.

Since visual field impairment is a symptom, to get rid of it it is necessary to eliminate the disease or pathology that caused the visual field defect. Therefore, if even a slight narrowing of the visual field or loss of parts of the visual field occurs, you must contact an ophthalmologist and neurologist. Treatment is prescribed depending on the cause of the visual impairment and can range from medication to surgery. It is impossible to ignore any disturbances in the visual field, otherwise complete loss of vision may occur (depending on the reason that triggered the disturbance in the visual field).

Light from an object that falls on the periphery of the retina allows you to see the object and determine some of its properties. Lateral vision is most sensitive to white color, to flickering objects. You can simultaneously perceive two objects in a field of vision covering an angle of 120°.

Types of lateral vision impairment

Peripheral vision loss can result from small areas of the retina that are not functioning. In this case, a person sees spots of a dark color, or an area of vision loss appears.

A narrowing of the field of view is also possible. It may even result in a small “island” of vision in the central area of the eye. In this case, a person sees the world around him as if looking through a small tube. Such changes are called tunnel vision.

Sometimes there is partial loss of the visual field in different volumes- a quarter, a half, and so on.

Causes of lateral vision impairment

There may be various reasons for which the peripheral ability to see is impaired. The most common are the following:

Damage to the retina of the eye. Damage may vary. In this case, minimal damage to the retinal nerve cells contributes to dysfunction. This entails impaired peripheral vision. Such injuries include vascular eye disease, retinal detachment, or retinal dissection. Often, degeneration (deterioration of biological characteristics) and dystrophy (systemic disorders) of the retina of the eye lead to the destruction of retinal nerve cells.
Glaucoma. This is a disease that is associated with increased intraocular pressure. The patient suffers damage to the optic nerve. And one of the characteristic symptoms of this disease is disturbances in the field of vision.
Damage to the optic nerve may result from poor circulation in the vessels that supply the nerve. Another cause may be injury, tumor, or inflammation of the optic nerve.
An increase in which damage to the optic nerve develops.
Brain damage. May be caused by injury, brain tumor, or vascular circulatory problems and hemorrhage.

Lateral vision is a necessary component of human vision. Deterioration or loss of peripheral vision is a symptom of many serious diseases. It is necessary to have your vision checked periodically. At the first sign of eye problems, you should seek help from a specialist. This is the only way to prevent the development of a serious illness.