home Audience 1 Deterioration of vision: causes of vision loss in children, age-related vision loss, treatment. Visual impairment - main causes

Deterioration of vision: causes of vision loss in children, age-related vision loss, treatment. Visual impairment - main causes

Most people who are born with good vision take it for granted and usually think little about its value. A person usually begins to appreciate vision when he encounters the first limitations of his capabilities due to loss of vision.

The very fact that the ability to see clearly is lost often upsets a person, but, as a rule, not for long. If preventive measures or efforts to preserve vision are undertaken for some time, the situation is soon smoothed out by spectacle correction or lenses, and prevention stops.

Perhaps only expensive surgical treatment forces citizens to take more seriously the preservation of their achievements. surgically results. What are the causes of decreased vision? Which situations can be resolved routinely, and which require an immediate visit to the doctor and emergency care?

Options for visual impairment

Decreased vision clarity

The norm of visual acuity for children over the age of five and adults is 1.0. This means that the human eye is able to clearly distinguish two points located at a distance of 1.45 meters, provided that the owner is looking at them at an angle of 1/60 degree.

Clarity of vision is lost with myopia, farsightedness, and astigmatism. These disorders relate to ametropia, that is, a condition where the image is projected outside the retina.

Myopia

Myopia or myopia is a condition where light rays project an image in front of the retina. At the same time, distance vision deteriorates. Myopia can be congenital (due to an elongated shape of the eyeball, when there is weakness of the ciliary or extraocular muscles) or acquired. Myopia is acquired as a result of irrational visual stress (reading and writing in a lying position, failure to maintain the best vision distance, frequent eye fatigue).

The main pathologies leading to the acquisition of myopia are spasm of accommodation, increased thickness of the cornea, traumatic dislocations and subluxations of the lens and its sclerosis in the elderly. Myopia can also be of vascular origin. Weak myopia is considered to be about minus three. Moderate - from minus 3.25 to minus six. Anything more is severe myopia. Progressive myopia is called when its numbers constantly increase against the background of stretching rear cameras eyes. The main complication of severe myopia is divergent strabismus.

Farsightedness

Farsightedness is the inability to see close up normally. Ophthalmologists call it hypermetropia. This means that the image will be formed behind the retina.

Congenital farsightedness is natural and is caused by the small longitudinal size of the eyeball. It may disappear as the child grows or may persist. In cases of abnormally small eye size, insufficient curvature of the cornea or lens.
Senile (when vision declines after 40) is a consequence of a decrease in the ability of the lens to change its curvature. This process goes through the stage of presbyopia (first temporary in people from 30 to 45), and then permanent (after 50-60 years).

Age-related deterioration of vision after 65 occurs because the accommodation of the eye (the ability to adjust the curvature of the lens to the needs of a person) is practically absent.

Both the lens (losing elasticity or changing curvature) and the ciliary muscle, which is no longer able to bend the lens normally, are to blame for this. On early stages Presbyopia can be compensated for by bright lighting. It doesn’t help in the later stages either. The first manifestations of the pathology are the inability to read close typeface within the distance of comfortable vision (25-30 centimeters), blurriness of objects when quickly moving the gaze from distant objects to close ones. Farsightedness can be complicated by increased intraocular pressure.

Astigmatism

Astigmatism in a primitive explanation is different visual acuity horizontally and vertically. In this case, any point is projected in the eye so that it turns out to be a blurry ellipse or figure eight. The pathology is associated with a violation of the shape of the lens, cornea or the entire eye. In addition to blurred vision, astigmatism is accompanied by double vision of objects, their blurring, and rapid eye fatigue. It can be combined with myopia (complex myopic) or farsightedness (complex hyperopic), and can also be mixed.

Double vision

This condition is called diplopia. With it, a visible object can double horizontally, vertically, diagonally, or two images are rotated relative to each other. Blame it all oculomotor muscles, whose work is not synchronized and which do not allow the eyes to converge to the target object as they should. Often, damage to the muscles themselves or the nerves that supply them in systemic diseases begins with diplopia.

The classic cause of double vision is strabismus (convergent or divergent). At the same time, a person cannot manage to direct both central foveae of the retina strictly along the course.
The second typical picture is alcohol poisoning. The toxic effect of ethanol disrupts the combined movement of the eye muscles.
Temporary double vision has been played out many times in movies and cartoons: when a hero is hit on the head, not only do sparks fly from his eyes, but the picture before his eyes moves apart.

These are all examples of binocular (two eyes) diplopia.

Double vision in one eye can develop when the cornea is too convex, the lens is subluxated, when the calcarine groove of the occipital region of the cerebral cortex is affected.

Binocular vision disorders

The ability to see with two eyes allows a person to expand the field of vision, improve its clarity by 40%, see the volume of an object, and evaluate its approximate size and shape. This is stereoscopic vision. Another important purpose is distance estimation. If one eye does not see or the difference in the eyes leaves several diopters, the weaker eye, which can cause diplopia, begins to be forcibly switched off by the cortex from the vision process.

First, binocular vision disappears, and then the weak eye may go completely blind. In addition to myopia and farsightedness with a large difference between the eyes, uncorrected astigmatism also leads to the subfrontal phenomenon. It is precisely the inability to estimate distance without spectacle correction forces many people to wear glasses or contact lenses while driving.

More often, binocular vision is absent with strabismus. Honestly speaking, almost no one has an ideal balance between the position of the eyes, but since even with deviations in muscle tone Binocular vision is preserved and does not require correction. If convergent divergent or vertical strabismus deprives a person of vision with both eyes, it is necessary to undergo surgery either best case scenario put on glasses.

Distortion of visual fields

The part of the surrounding reality visible to the fixed eye is the field of vision. In spatial terms, this is not a field at all, but rather a 3D hill, at the top of which visual acuity is highest. Worsening towards the base, more along the slope near the nose and less along the temporal. The field of vision is limited by the anatomical protrusions of the facial skull, and at the optical level by the capabilities of the retina.

For white color, the normal visual field is: inward - 55 degrees, upward - 50, downward - 65, outward - 90. (see picture of the visual field).

For one eye, the field of view is divided into two vertical and two horizontal halves.

Visual fields can change in the form of scotomas (dark spots), in the form of concentric or local narrowings (hemianopsia).

Deviations in color perception

Color blindness is a congenital defect in distinguishing between red and green that is not recognized by the patient. More often detected in men.
Temporal shifts in the perception of white– a consequence of surgery to remove the affected lens. Shifts towards blue, yellow, and red colors may develop, that is, white will be bluish. yellowish reddish, like an unregulated monitor.
After cataract removal, the brightness of colors may also change.: blue becomes more saturated, and yellow and red fade, turn pale.
Shift of perception towards long waves(yellowing, redness of objects) may indicate retinal or optic nerve dystrophy.
Objects become discolored with old degeneration of the macular region, which is no longer progressing.

Most often, color disturbances affect the central part of the visual field (within 10 degrees).

Blindness

In the absence of an eye (congenital or) acquired, with complete retinal detachment, atrophy of the optic nerve, blindness is called amaurosis. If the previously seeing eye is suppressed by the cortex against the background of strabismus, a large difference in diopters between the eyes, with clouding of the media of the eye, with Kaufman and Benche syndromes, ophthalmoplegia with severe ptosis (drooping of the eyelid), amblyopia develops.

Causes of visual impairment

Changes in the transparency of the eye media (pathologies of the cornea, lens).
Muscle pathologies
Retinal abnormalities
Optic nerve lesions
Deviations in the cortical center

Normally, the transparent media of the eyeball (cornea, lens, vitreous body) transmit and refract light rays like lenses. With pathological infectious-inflammatory, autoimmune or dystrophic processes in these lenses, the degree of their transparency changes, which becomes an obstacle to the path of light rays.

Pathologies of the cornea, lens

Keratitis

The pathology is characterized by clouding, ulceration of the cornea, pain and redness in the eye.
Photophobia is also present.
Lacrimation and decreased shine of the cornea up to the formation of an opaque cataract.

More than half of viral keratitis is caused by herpes (dendritic keratitis). In this case, a damaged nerve trunk is visible in the eye in the form of a tree branch. A creeping corneal ulcer is the result of a herpetic lesion or chronic injury to the cornea by foreign bodies. Amebic keratitis often leads to ulcers, which affects lovers of cheap, low-quality lenses and those who do not follow hygienic rules for using lenses.

When the eye is “burned” by welding or looking at the sun with an unprotected eye, photokeratitis develops. In addition to ulcerative keratitis, there is non-ulcerative keratitis. The disease can affect only the superficial layers of the cornea or be deep.

Corneal opacities are the result of inflammation or dystrophy; a cataract is a scar. Opacities in the form of clouds or spots reduce visual acuity and cause astigmatism. The thorn limits vision to light perception.

Cataract

- This is clouding of the lens. At the same time, metabolism is disrupted, structural proteins are destroyed, elasticity and transparency are lost. The congenital form of the disease is the result of viral, autoimmune or toxic influences on the fetus in utero or genetic pathology.

Cloudiness of the lens is acquired, as age-related dystrophy, the result of mechanical or chemical trauma, radiation exposure, poisoning with naphthalene, ergot, mercury vapor, thallium, trinitrotoluene). Posterior capsular cataract is the lot of people over 60 who quickly lose vision, nuclear cataract gradually increases the degree of myopia, age-related cortical cataract makes the surrounding blurry.

Vitreous opacification

Cloudiness of the vitreous body (its destruction) is perceived by the patient as threads or dots floating in front of the eye when moving the gaze. This is a consequence of thickening and loss of transparency of individual fibers of the vitreous body, which develop with age-related dystrophy, arterial hypertension and other vascular pathologies, diabetes mellitus, hormonal changes or therapy with glucocorticoids, opacities are perceived in the form of simple or complex (webs, balls, plates) figures. Sometimes areas of degeneration are perceived by the retina, and then flashes appear in the eyes.

Muscle pathologies

Vision depends on the ciliary and oculomotor muscles. Their dysfunction also impairs vision. The entire range of movements of the eyeball is provided by only six muscles. They are stimulated by 6, 4 and 3 pairs of nerves in the cranial region.

Ciliary muscle

The ciliary muscle helps the lens to bend, participates in the outflow of intraocular fluid and stimulates the blood supply to certain parts of the eye. Muscle function is disrupted by vascular spasm in the vertebrobasilar region of the brain (for example, vertebral artery syndrome in osteochondrosis), hypothalamic syndrome, spinal scoliosis and other causes of cerebral blood flow disorders. The cause may also be traumatic brain injury. This leads primarily to a spasm of accommodation, and then to the development of myopia. In some works by domestic ophthalmologists, a relationship has been identified between injuries to the cervical region of fetuses during childbirth and the development of early forms acquired myopia.

Oculomotor nerves and muscles responsible for eye movement

The oculomotor nerves regulate not only the muscles that control the eyeball, but also the muscles that constrict and dilate the pupil, as well as the levator muscle. upper eyelid. Most often, the nerve suffers from microinfarction due to hypertension and diabetes. Damage to all nerve fibers leads to the following symptoms of visual impairment: divergent strabismus, double vision, drooping of the eyelid, dilation of the pupil without reaction to light, poor near vision due to accommodation paralysis, limitation of eye movements inward, up and down. Often, with strokes, nerve damage is included in the program of pathological syndromes (Weber, Claude, Benedict).

Abducens nerve damage

Damage to the abducens nerve (which can cause meningioma, internal carotid aneurysm, nasopharyngeal cancer, pituitary tumor, head injury, intracranial hypertension, complicated otitis media, central nervous system tumors, multiple sclerosis, stroke, vascular infarctions along the nerve due to arterial hypertension or diabetes mellitus) interfere with moving the eye to the side. The patient suffers from horizontal double vision, which intensifies when looking in the affected direction. In children, congenital lesions of the abducens nerve are included in the program of Mobius and Duane syndromes.

When the trochlear nerve is affected, double vision appears in the vertical or oblique plane. It intensifies when you look down. The head often takes a forced position (turning and tilting in the healthy direction). The most common causes of nerve damage are traumatic brain injury, microinfarction of the nerve, and myasthenia gravis.

Retinal pathologies

Retinal detachment (idiopathic, degenerative or traumatic) occurs at the site of membrane ruptures against the background of diabetic retinopathy, myopia, trauma, or intraocular tumor. Often the retina detaches after clouding of the vitreous body, which pulls it along with it.
Spot degeneration, vitelline degeneration, macular degeneration are hereditary pathologies that are worth thinking about when a child’s vision declines very significantly in preschool age.
Hydrocyanic dystrophy is typical for people over 60.
Strandberg-Grönblad syndrome is the formation of stripes in the retina that resemble blood vessels and replace cones and rods.
Angiomas are vascular tumors of the retina that occur in adolescence and lead to retinal tears and detachment.
Varicose veins of the retina (Coats' retinitis) are dilation of venous vessels, which leads to hemorrhages.
Albinism with underdevelopment of the pigment layer of the retina gives a pink coloration of the fundus and discoloration of the iris.
Thrombosis or embolism of the central retinal artery leads to sudden blindness.
Retinoblastoma is a malignant tumor of the retina that grows into it.
Inflammation of the retina (uveitis) causes not only blurred vision, but also flashes and sparks in the field of vision. Distortions in the shapes and outlines and sizes of objects may be observed. Sometimes night blindness develops.

Signs of optic nerve diseases

If the nerve is completely interrupted, the eye on the affected side will go blind. His pupil narrows and does not react to light, but may narrow if shined into the healthy eye.
If some of the nerve fibers are damaged, then vision simply decreases or loss of vision occurs (see distortion of visual fields).
Most often the nerve is affected by injuries, vascular diseases, tumors, and toxic lesions.
Nerve anomalies – coloboma, hamartoma, double nerve disc.
Disc atrophy (against the background of multiple sclerosis, ischemia, trauma, neurosyphilis, after meningoencephalitis) causes a narrowing of the visual fields and a drop in its acuity, which cannot be corrected.

This and cortical disorders are discussed in the next two sections.

Temporary loss of vision

Eye fatigue

The most commonplace situation is called asthenopia. This is eye strain due to irrational visual load (for example, sitting for many hours in front of a monitor screen, TV, reading from a sheet in low light, driving a car at night). In this case, the muscles that regulate the functioning of the eye become overstrained. Pain in the eyes and lacrimation appear. It is difficult for a person to concentrate on small print or details of an image, and blurriness or a veil may appear before his eyes. This is often combined with a headache.

False myopia

Accommodation spasm (false myopia) often affects children and adolescents. Its clinical picture is similar to asthenopia. Transient disturbance vision near or far is caused by fatigue and spasm of the ciliary muscle, which changes the curvature of the lens.

"Night blindness" - nyctalopia and hemeralopia

Deterioration of vision at dusk is a consequence of a deficiency of vitamins A, PP and B. This disease is popularly called night blindness, and its scientific names are nyctalopia and hemeralopia. At the same time, twilight vision suffers. In addition to hypovitaminosis, diseases of the retina and optic nerve can lead to night blindness. There are also congenital forms of pathology. At the same time, visual acuity weakens, color perception decreases, a person’s spatial orientation is disrupted, and visual fields are narrowed.

Vascular spasms

Transient visual disturbances may indicate vascular spasm in the retina or brain. Such situations are associated with hypertensive crises ( sharp jumps Blood pressure), chronic cerebrovascular accidents (due to atherosclerosis, vertebral artery syndrome, cerebral amyloidosis, blood diseases, vascular anomalies, venous hypertension). As a rule, there is blurred vision, flickering of spots before the eyes, and darkening of the eyes. Combined symptoms may also occur, for example, hearing and vision impairment or dizziness, blurred vision.

Migraine

May be accompanied by temporary blurred vision against the background of severe vasospasm. Often, pain in the head is accompanied by the appearance of an aura in the form of flickering scotomas (flickering or floating dark spots in front of the eyes).

Intraocular pressure

If intraocular pressure is normal from 9 to 22 mmHg, then an acute attack of glaucoma can raise it to 50-70 or higher. At the same time sharp headache half the head and eyeball accompany a one-sided process. If both eyes are affected, the whole head hurts. In addition, blurred vision, rainbow circles before the eyes, or dark spots(scotomy). Autonomic disorders (nausea, vomiting, heart pain) are often associated.

Medicines

Drug effects can also lead to transient myopia. This occurs when taking high doses of sulfonamides.

Sudden deterioration of vision

Most often, a stroke, brain tumor, retinal detachment or eye injury are to blame for irreparable sudden loss of vision. Loss of vision can occur suddenly or within a few hours.

Reversible vision loss

If we are talking about acute reversible loss of vision in both eyes, then the culprit is an attack oxygen starvation visual cortex ( ischemic attack as part of a chronic cerebrovascular accident or ischemic stroke in the posterior cerebral artery basin) or a severe migraine attack. In this case, there is not only a headache and blurred vision, but also a color perception disorder in the form of fading of objects.

A rare form is postpartum blindness due to embolism of the branches of the posterior cerebral artery.
After operations or injuries with loss of large volumes of blood and a drop in blood pressure, posterior ischemic optic neuropathy often develops. The consequence is an amblyopic attack.
In case of poisoning with surrogate alcohol ( methyl alcohol), chloroquine, quinine, and phenothiazine derivatives, bilateral vision loss (or at least central scotoma) occurs within the first 24 hours. Approximately 85% of patients recover; in the rest, blindness is complete or partial.
There are also rare familial forms of temporary blindness lasting up to 20 seconds with a sudden change in lighting or body position.

Permanent vision loss

Sudden loss of vision in one eye is primarily suspicious for retinal dissection, central retinal vein thrombosis, or arterial occlusion.

If the situation develops due to a head injury, exclude a fracture of the skull bones with damage to the walls of the optic nerve canal. This can only be corrected by emergency surgical decompression.
An acute attack of glaucoma (increased intraocular pressure) is accompanied by redness of the eye, loss of vision, pain in the head, heart or abdomen, the density of the eyeball is comparable to the density of the table.
The cause may also be ischemic optic neuropathy due to temporal arteritis and occlusion of the posterior ciliary artery. The idea of it is suggested by pain in the temple that appears and persists for several months, fatigue, pain in the joints, lack of appetite, increase in ESR in an elderly patient.
At ischemic stroke one eye can also go blind (see).

Why vision drops sharply should be investigated by an ophthalmologist together with a neurologist, since vascular pathologies most often come to the fore as the causes of sudden vision loss.

Diagnostics

To get a complete picture of the state of the visual analyzer. An ophthalmologist or ophthalmologist today has a whole range of diagnostic capabilities. A number of studies are based on hardware methods. During the examination they usually use:

Measuring visual acuity (using tables).
Measuring the refractive capabilities of the eye (hardware method)
Determination of intraocular pressure.
Checking visual fields.
Examination of the fundus (changes in the retina during wide pupil) with examination of the optic nerve head.
Biomicroscopy (examination of the eye through a microscope).
Echobiometry (determining the length of the eye).
Pachymetry (measuring the thickness and angle of curvature of the cornea).
Computer keratotopography (determining the profile of the cornea).
Ultrasound of ocular structures.
Measuring the production of tear fluid.

Treatment of vision impairment

Most often, in case of vision problems, they resort to conservative correction or surgical treatment.

Conservative treatment

The conservative part of the program includes correction with glasses. Lenses, hardware techniques, gymnastics and eye massage (see). For degenerative pathologies, vitamins are added.

Spectacle correction allows you to reduce the risks of strabismus, retinal detachment due to myopia, hyperopia, and also correct complex species visual impairment (astigmatism combined with myopia or hypermetropia). Glasses somewhat limit the field of vision and create difficulties when playing sports, but they do the job quite well, allowing you to supply your eyes with any type of necessary lenses.
Aesthetes and those who make money thanks to their appearance resort to lenses. The main complaints about this type of correction are complex hygienic requirements. Risks of bacterial and protozoal complications, lack of full air penetration into the eye. Generally, modern lenses They offer both disposable and breathable options.
Gymnastics and massage help improve blood supply to all structures of the eye, make the oculomotor and ciliary muscles work, and are suitable for correcting simple weak degrees of myopia or farsightedness.
Hardware techniques – classes with an instructor with or without glasses on special installations that train the eye muscles.

Operational aids

Cataracts today are successfully treated only by removing the clouded lens with or without its replacement.
Tumor and some vascular processes can also be corrected exclusively by surgery.
Laser welding of the retina allows you to solve the problem of tears or partial detachment.
The PRK method is the earliest variation of corneal laser correction. The method is quite traumatic, requires long-term rehabilitation and is contraindicated for both eyes at the same time.
Lasers are also used today to correct visual acuity (farsightedness of 4 diopters and myopia of 15, astigmatism within 3). LASIK method(laser keratomileusis) combine mechanical keratoplasty and laser beams. A corneal flap is peeled off with a keratome, the profile of which is adjusted with a laser. As a result, the cornea decreases in thickness. The flap is welded into place using a laser. Super-LASIK is a variation of the operation with very gentle grinding of the corneal flap, which is based on data on its curvature and thickness. Epi-LASIK allows you to avoid staining the corneal epithelial cells with alcohol and correct marginal distortions (aberrations) of vision. FEMTO-LASIK involves the formation of a corneal flap and its treatment with a laser.
Laser correction is painless, leaves no stitches, and requires little time, including recovery. But some of the long-term results leave much to be desired (dry eye syndrome, inflammatory changes in the cornea may occur, the corneal epithelium may become excessively rough, and sometimes corneal ingrowths may develop).
Surgical laser intervention is not performed for pregnant women, lactating women, or children under 18. This technique cannot be used on a single eye, with glaucoma, insufficient corneal thickness, autoimmune pathologies, with cataracts, immunodeficiency, progressive forms of myopia, operated retinal detachment, with herpes.

Thus, the problems of vision loss are very diverse. They often progress, leading to complete loss of vision. Therefore it is early detection pathologies of the visual analyzer, their prevention and correction can protect a person from disability.

Experienced ophthalmologists know that visual impairment can be a sign of serious pathology. Millions of people around the world face this problem. With age, vision deteriorates. This is a natural process caused by aging. A person sees thanks to the coordinated work of various structures.

Deterioration of human vision

The organ of vision is very complex - it is formed by the eyeball, appendages and nerve. Obtaining an image of the object in question is achieved through the operation of an optical system. It includes the cornea, vitreous body, lens, aqueous humor and retina. The optical power of the eye is measured in diopters.

The refractive power of the eye is called refraction. The following main types of visual impairment are known:

nearsightedness (myopia);
astigmatism;

Presbyopia is highlighted separately. It develops in older people. The reason is a decrease in the elasticity of the lens. Vision problems include amblyopia. This is a condition in which . More than 300 million people worldwide have a visual impairment. The risk group includes people over 50 years of age.

With age, the incidence of pathology increases.

Young children often get sick. Without proper help, low vision can lead to disability. The most common cause of blindness is cataracts. Not everyone knows the types of visual impairment (classification). The following disorders of the function of the organ of vision are distinguished:

A dangerous condition is amaurosis.

Main etiological factors

If a person’s vision has decreased, there can be many reasons for this. Important role The following factors play a role:

retinal detachment of the eye;
cataract (clouding of the lens);
glaucoma;
macular degeneration;
vitreous detachment;
retinal tear;
diabetes;
injuries;
entry of foreign bodies;
hemorrhage;
injuries;
corneal ulcer;
keratitis;
pituitary tumor;
pathology of the thyroid gland;
strabismus;
poisoning with methyl alcohol and alcohol surrogates;
dysfunction of the ciliary muscle;
damage to the abducens nerve;
congenital developmental anomalies;
vascular thrombosis;
angioma;
nerve abnormalities;

There are various factors that lead to decreased vision. This may include overwork, sedentary work, prolonged viewing of television, working at a computer, stress, disruption of sleep and wakefulness. Sometimes a pathology such as night blindness develops. It is caused by an acute lack of vitamin A in the body.

Causes of decreased vision in schoolchildren include: reading in public transport, at poor lighting and in a supine position.

Improper organization of the workplace when working at a computer has a negative impact on the eyes. Predisposing factors are smoking, poor nutrition, low physical activity and alcohol consumption.

Development of myopia in humans

Decreased vision clarity is often detected. This is a pathological condition in which the refraction of the eye is impaired. It is based on enhanced refraction of rays. As a result, the image does not appear on the retina itself, but slightly in front of it. Otherwise, this condition is called myopia. Such people see poorly from any distance, but better up close.

Up to 30% of adults suffer from myopia. The first symptoms often appear during adolescence. Every ophthalmologist knows why vision deteriorates. Risk factors for developing myopia are:

Manifestations of myopia increase with a lack of zinc, manganese, copper and chromium in the body. Very often, myopia is combined with astigmatism, strabismus and amblyopia. There are 3 degrees of myopia. With mild myopia, the refractive power of the eye changes by no more than 3 diopters. With an average degree of myopia, this value reaches 6 diopters. Severe myopia is characterized by a refractive error of more than 6 diopters.

Poor eyesight with myopia, it is often detected during preventive examinations.

The visual acuity of objects may deteriorate even at school. The following symptoms are possible:

If myopia progresses rapidly, it is necessary to change glasses frequently or contact lenses. Younger students may have problems with their studies. Sometimes mild bulging eyes develop. The reason is the widening of the palpebral fissure against the background of an increase in the size of the eyeball. The functioning of the vitreous body may deteriorate.

This is manifested by the presence of threads or flies before the eyes.

If vision has deteriorated, the cause may be false myopia. It develops with increased tone of the ciliary muscle. Myopia may progress annually, or eye function may not change over time. In the latter case, there is no need to change glasses.

If near vision has deteriorated, the cause may be hypermetropia. This is the exact opposite of myopia. With it, a person sees far away objects better. Reading books becomes difficult. Vision problems such as hyperopia occur in 35–40% of people. Physiological farsightedness is diagnosed in children 7–12 years old.

The development of this condition is based on a decrease in the diameter of the eyeball in the anteroposterior direction or a decrease in refractive power. The exact causes of hypermetropia have not been established. With farsightedness, there are the following signs of vision impairment:

difficulty seeing one or both eyes at close range;
convergent strabismus;
feeling of fullness;
fatigue;
headache;
feeling of sand in the eyes.

The severity of symptoms is determined by the degree of hypermetropia. If vision decreases quickly, then this is a bad prognostic sign. At weak degree hyperopia of one eye or both eyes, no complaints. The function of the organ is maintained due to the tension of accommodation. In patients with moderately poor vision, when working at close range, symptoms such as pain in the eyes and eyebrows, blurriness of objects, discomfort, and merging of small objects appear.

In the early stages, it is difficult to understand that a person is farsighted. With severe hypermetropia, asthenopic syndrome is pronounced. There is deterioration in near and distance vision. This eye disease is characterized by a combination with blepharitis and conjunctivitis. In young children, farsightedness leads to squint.

Astigmatism in men and women

Experienced doctors know not only the classification of visual impairments, but also such pathology as astigmatism. With it, a distorted image is formed on the retina. Deterioration of vision in one eye is observed when the refraction changes by 1 diopter or more. Astigmatism is diagnosed less frequently than myopia and hypermetropia. His share in general structure refractive errors reach 10%. Not everyone knows why vision decreases with astigmatism.

The main reason is a change in the configuration of the lens or cornea. The hereditary factor is of no small importance. During the laying of organs, uneven pressure of the eye appendages and muscles on the membranes is possible. This increases the risk of developing astigmatism in the future.

Causes of decreased vision include corneal scarring, keratitis, and keratoconus.

All this can lead to the development of acquired astigmatism. Known 2 clinical forms this pathology: right and wrong. Astigmatism is often combined with myopia and farsightedness. A person learns that his vision is deteriorating, most often in preschool or school age.

Children confuse letters or change their arrangement in words. They complain of poor vision. Surrounding objects appear blurry and distorted. Pain often appears in the area of the eyebrows and head. Such people cannot stand glasses. The clarity of vision of objects disappears. Additional symptoms include burning, double vision and hyperemia. When working visually, the eyes get tired very quickly. Patients cannot accurately estimate the distance between objects.

Twilight vision impairment

You need to know not only the causes of poor vision, but also what hemeralopia is. Otherwise, this pathology is called night blindness. Such people see poorly in low light and in the dark. The main cause is a violation of rhodopsin synthesis. This is a pigment that is formed in the rod-shaped light-sensitive cells of the retina of the eyes.

Formation occurs with the participation of vitamin A.

The cause of hemeralopia may also lie in a change in the ratio of rods and cones towards the latter. This causes vision problems. Men and women get sick equally often. This pathology never develops in people who live in the far north under polar night conditions.

Normally, a person who is in a dark room for about 5 minutes adapts. In hemeralopia, dark adaptation is severely impaired. Known following reasons Deterioration of vision in low light conditions:

In the congenital form of the disease, it is almost impossible to stop the loss of vision. Treatment is ineffective. The first signs are detected in early childhood. Symptoms of visual impairment in hemeralopia include impaired orientation in the dark and decreased visual acuity of objects in the twilight. There are no complaints during the daytime.

Sick children are afraid of the dark and cry if left in such conditions.

The perception of blue and yellow colors is often impaired. The field of view is somewhat narrowed. If the cause is a lack of retinol, then upon examination, flat and dry plaques appear in the conjunctival area. Other symptoms include dry skin, bleeding gums and hyperkeratosis.

Development of diplopia in humans

Vision often deteriorates due to diplopia. This is a pathological condition in which surrounding objects appear double. There are horizontal and vertical diplopia. This disease may be a symptom of a serious pathology. The following causes of diplopia are known:

When the function of the organ of vision is impaired, double vision occurs in both or one eye. Additional symptoms of diplopia include dizziness, strabismus, and impaired spatial orientation. Sick people often change the position of their head. This helps improve vision.

Cause of retinal detachment

If vision has deteriorated, the cause may be a detachment of the retina of the eye. This is a dangerous pathology that can cause blindness. The incidence rate is 5–10 people per 100,000. It is the most common cause of blindness and disability. There are 3 known forms of this pathology:

traumatic;
primary;
secondary.

The following factors contribute to detachment:

Historical evidence indicates that detachment most often develops in people with refractive error. Most often, 1 eye is affected. Dystrophy and viral infections are factors affecting the condition of the retina. With detachment, there is a rapid deterioration in vision in one eye. Additional signs are a feeling of a veil before the eyes, the presence of a shadow in one of the fields of vision, flashes and sparks. In the early stages, symptoms are mild.

Lens dysfunction

When vision loss occurs, the cause may lie in clouding of the lens. The latter is an elastic lens necessary for refraction of rays. It is part of the optical system of the eye. The lens is located behind the pupil. The following types of cataracts are known:

traumatic;
age;
secondary;
toxic.

How older man, the greater the risk of lens opacification. The causes of decreased vision are varied. Every person should understand that cataracts are most often acquired. The total number of patients in the world reaches 17 million.

Increasingly, symptoms of cataracts are being detected in the working population.

Not everyone knows what causes visual impairment. The following factors are involved in the development of cataracts:

genetic predisposition;
infection of the fetus during pregnancy;
taking hormonal medications;
diabetes;
irradiation;
autoimmune diseases;
exposure to infrared rays;
chemical and mechanical injuries;
thermal burns;
poisoning

You can worsen your vision with this disease if you move little, spend a lot of time at the computer and TV, be exposed to strong insolation and eat poorly. Cataracts are characterized by complete or partial loss of vision. Its severity is determined by the stage of the disease. In the initial stages, there is a weakening of eye function.

Patients complain of “flying spots” and dots.

During the swelling stage, vision decreases even more. The lens enlarges. The pupil closes slowly. Glaucoma often develops. At the stage of mature cataracts, people cease to distinguish objects. Vision in one or both eyes practically disappears. A person can only recognize light rays. At the stage of overripe cataracts, people do not distinguish between the sun and colors. Iridocyclitis develops.

Deterioration of vision due to glaucoma

Causes of visual impairment include glaucoma. This is a group of diseases characterized by the following symptoms: high intraocular pressure and damage to the optic nerve. In 15% of blind people, glaucoma was the cause of vision loss. Normal IOP is healthy people ranges from 18 to 26 mmHg. Art. The prevalence of glaucoma among the population reaches 3%.

The incidence rate increases steadily with age. This problem is often identified in schoolchildren with visual impairments. Intraocular pressure increases due to increased production aqueous humor or difficulty in its outflow. Predisposing factors are the following:

congenital developmental anomalies;
cervical osteochondrosis;
hypertension;
atherosclerosis;
diabetes;
injuries;
eye tumors;
iridocyclitis;
scleritis;
keratitis;
refractive error such as farsightedness;
injuries;
hemophthalmos.

Glaucoma can be open-angle or closed-angle. Loss of vision in one eye or both is possible with the angle-closure type during an attack. If a person is left untreated, glaucoma becomes chronic. In this case, there is a high risk of optic nerve atrophy and blindness. You need to know not only what causes vision damage, but also how glaucoma manifests itself.

The following symptoms are observed with this disease:

blurred vision;
headache;
the presence of rainbow circles;
decreased vision in dim light.

Deterioration of vision due to nervous conditions in glaucoma is a common occurrence. During an attack, pain appears, the pupil dilates and redness occurs. Upon examination, you will notice that the pupil becomes greenish in color.

In the open-angle form, central and peripheral vision is impaired.

Patient examination plan

If you have complaints, you should contact an ophthalmologist. The following studies will be required:

ophthalmoscopy;
refractometry;
assessing the visual acuity of objects using tables;
biomicroscopy;
Ultrasound of the eyeballs;
pachymetry;
fundus examination;
visual field assessment;
computer keratotopography;
measuring the length of the eyeballs;
general clinical tests;
tomography;
biochemical analysis.

If necessary, campimetry is performed. This method examines the blind spot. Gonioscopy is required. During it, the iridocorneal angle is examined. Tonometry helps to identify visual defects with Maklakov. The main research method is visometry. The data obtained is compared with those that were previously available.

Ancillary research methods include stress tests, Heidelberg retinotomography and rheoophthalmography. The results of biomicroscopy are of great value. During it, the condition of all structures of the eyeball is determined under high magnification. The examination is carried out using a slit lamp. To determine the cause of a person's vision loss, the condition of the brain and other organs is assessed. This is of great importance for subsequent treatment.

Treatment methods for patients

If vision defects are detected, treatment is required. It is determined by the underlying disease. Not everyone knows how to get rid of myopia. For myopia, courses of drug therapy are required 1–2 times a year. General treatment includes taking vitamins, using mydriatics, calcium supplements, drugs that improve cerebral blood flow, and physiotherapy. Vision correction is required with glasses or contact lenses.

Patients sit down, and the doctor selects the necessary lenses. With rapid progress of myopia, surgery (scleroplasty or thermocoagulation) is required. Laser therapy has a good effect. Interventions such as LASIK and LASEK are performed. Every experienced ophthalmologist knows how to stop vision deterioration due to farsightedness.

The main method of correction is wearing glasses.

For hypermetropia, hardware treatment is performed. Laser therapy is used from the age of 18. Photorefractive keratectomy is effective. In severe cases, lens removal may be necessary. If vision defects are caused by cataracts, then treatment depends on the stage of the disease.

For the senile form of lens clouding, eye drops based on taurine, amino acids, vitamins and antioxidants are used. Conservative treatment, which is the most common, is ineffective. The operation is indicated for swelling and overripe cataracts, as well as subluxation of the lens and complications such as glaucoma.

Extraction or phacoemulsification is performed. In the latter case, the lens is replaced with an intraocular lens. If glaucoma is detected, regardless of the degree of visual impairment, drug therapy is required. Miotics, sympaomimetics, prostaglandins (Latanoprost, Xalatan), beta-blockers (Betoftan, Betoptik, Betoptik S, Betaxolol), alpha and beta-blockers (Proxodolol) are used.

Radical treatment is effective. If vision has decreased due to viral or bacterial diseases, then local antimicrobial and anti-inflammatory drugs are prescribed. All patients need to reduce visual stress, do eye exercises, give up smoking and alcohol, move more and spend less time on gadgets. Traumatic gaming activities are prohibited.

Experienced ophthalmologists know not only the structure of the visual organ defect, but also measures to prevent eye diseases. Specific prevention has not been developed. To maintain good vision into old age, you need to adhere to the following rules:

take breaks during visual work;
perform eye exercises;
blink more often when working at the computer and reading books;
limit the time spent watching the TV screen;
normalize sleep;
eat more foods rich in vitamin A and C;
use special glasses while working;
exclude any head injuries;
move more;
treat diabetes mellitus in a timely manner;
lead a healthy lifestyle;
prevent inflammatory diseases of the cornea and other eye structures;
engage in light sports.

To prevent visual impairment from occurring in the future, when working at a computer you must:

maintain the proper distance from the screen to the eyes;
work in a comfortable chair with armrests and footrest;
take a break of 15–20 minutes every hour;
periodically look out the window;
massage your eyelids with your eyes closed;
Place the monitor at eye level.

WITH for preventive purposes you can do simple exercises. First, you need to look at the finger located in front of your eyes, and then turn your gaze to distant objects. This exercise eliminates the spasm of accommodation and relaxes the muscles. An important aspect prevention is maintaining healthy image life.

This means giving up cigarettes and alcohol, frequent walks, and playing sports.

In old age, prevention of visual impairment is difficult. Everyone knows what to do with an elderly person with hypermetropia or other pathology. an experienced doctor. Secondary prevention comes down to proper treatment and strict adherence to all the ophthalmologist’s prescriptions. Deterioration of vision can be a sign of very dangerous diseases. The prognosis is determined by the timeliness of treatment and diagnosis.

Vision is the most powerful source of our knowledge about the external world - perhaps one of the most complex, amazing and beautiful properties of living matter. His loss is a huge misfortune for a person.

Nature has solved the problem of vision in many ways, creating various systems eyes, surprisingly well adapted to the conditions of human life and animal habitats. But with all the variety of patents of “living” nature for vision and the difference in the construction of the optical apparatus of the eye, its internal mechanisms are similar: they are based on subtle primary chemical and electrical changes in the retina of the eye, which lead to the emergence of nerve impulses that carry processed visual vision to the brain. information.

Eyes are a valuable, amazing gift of nature. They reflect everything we feel: joy and suffering, indifference, love and hatred. The eyes are not only the mirror of the soul, but also, as it were, a mirror general condition health. The eyes are the most important sense organ, so they deserve exceptional attention. Eyes also play a very important role in the overall aesthetic appearance of a person. But with all this, the eyes are a very sensitive and easily injured organ. For example, too bright light causes pain to the eyes; Polluted air, smoke, and dust cause watery eyes and sometimes even inflammation of the eyes. The eyes should always be clean and shining. And in order for them to be like this, daily, thorough eye care is necessary.

The lack of movement of modern man inevitably has a detrimental effect on functional properties visual apparatus - our eyes. In addition, excessive information load on the eyes and brain today leads to serious disorders and diseases. In developed countries, unfortunately, every fourth person is myopic. Age-related changes in the eye also increase, leading to farsightedness. And this issue has arisen especially acutely recently due to harmful influence computer displays for vision. One of the main reasons for this increase in eye disorders is insufficient training, and therefore weakness of the intraocular and periocular muscles.

The work of domestic and foreign scientists has proven that special training exercises for the intraocular and periocular muscles can lead to stabilization and even reverse development of myopia and farsightedness. Training the eye muscles also has a beneficial effect on the performance of operators at the display. However, the widespread practical use of physical exercises for the prevention of various refractive disorders * of the eye, especially myopia, and for restoring the performance of the main intraocular muscle - the ciliary muscle - is hampered by the lack of special mass manuals and guidelines, as well as special devices- video simulators - technical means of a new class, which have not yet been produced by industry. The first versions of technical video simulators have already been created at the Moscow Regional State Institute physical culture.

Can special physical exercises help with eye diseases?

It is well known that thought and movement are as inextricably linked as vision and movement, since the visual organ itself is constantly in motion. Father of Russian physiology I.M. Sechenov closely linked visual perception with the activity of the muscular apparatus of the eyes. He believed that the muscles of the eyes not only ensure a change in the position of the eyes in the orbit, but also serve as an apparatus through which consciousness receives information about the spatial relations of the external world.

The question arises, what specific special movements can be recommended to prevent eye problems? How can we use them to eliminate existing violations?

Moving on to the consideration of special motor exercises for visual organs, let us point out, first of all, that back in the 1920s, the famous school of Dr. Bates arose in America, using special exercises to correct eye defects. This school had many supporters: O. Huxley, M. Corbet, etc. In our country, the most famous system of visual training was proposed by professors A.N. Dashevsky and E.S. Avetisov, Candidate of Technical Sciences Yu.A. Utekhin.

Thus, they developed a special method of optical-motor training, which is based on a dynamic principle: contraction of the ciliary muscle of the eye alternates with its relaxation, which can be achieved by quickly changing positive and negative lenses in front of the eye. At the same time, an interesting “after recoil” effect of the ciliary muscle was discovered, which occurs after sudden removal of the load. Apparently, it indicates the manifestation of the accumulated potential energy of the tendon elements of the finest motor system inside the eye itself.

The peculiarity of the proposed method is the use of a dynamic variable mode of training the ciliary muscle. In general, for the first time the principle of variability in sports training was introduced by Dr. medical sciences Professor A. N. Vorobyov.

The experience of using a complex of general strengthening health-improving gymnastics for the eyes, carried out in Moscow and the Moscow region for people with myopia and age-related manifestations of farsightedness, confirms the effectiveness of using physical education means in ophthalmological practice. More than 500 people completed 2-month courses, becoming familiar with the technique of using special visual gymnastics.

The results of the training exceeded all expectations: for a relatively a short time indicators of central visual acuity, both near and far, and the volume of accommodation have improved*; visual fatigue has sharply decreased, especially after intense visual work; general health has improved.

Besides, different kinds simulators for training the eye muscles for health purposes (for myopia, farsightedness in adults and children and to reduce visual fatigue), as well as special lensless and prismatic glasses that can dramatically improve visual acuity.

Main causes of visual impairment

Poor vision is the inability of the eye to adapt to the instinctive physiological act of seeing. Myopia, or myopia, farsightedness, or hypermetropia, astigmatism are the main types of visual impairment.

Myopia, farsightedness and their causes.

Normal vision is called proportionate, or emmetropic. Myopic people (myopes) see close objects well, distant objects poorly, and farsighted people (hypermetropes), on the contrary. Almost two thirds of all humanity are farsighted or nearsighted, that is, they have ametropic eyes.

In myopic people, due to the increased power of refractive media due to the increased size of the eyeball, light rays from distant objects are focused in front of the retina. As a result, a clear image is not obtained in the area of the macula, and distant objects are seen blurry. But rays of light from close objects in a myopic eye converge precisely on the retina and give a clear image without strain or with minimal strain during accommodation. Myopic people can read for hours and work with very small details without experiencing visual fatigue.

Farsighted eyes, on the contrary, are characterized by weak refractive power or insufficient dimensions along the anterior-posterior axis. Light rays from distant and close objects in such an eye are refracted less than necessary, and a clear image on the retina is not obtained, since the focus is behind the retina. These changes in the focusing conditions of the image in the eye are called refractive.

For far-sighted and near-sighted people, vision is improved with glasses. A convex glass placed in front of the far-sighted eye increases the refractive power of the eye, the focus of light rays is transferred precisely to the retina, and the eye works with less strain. Concave glass placed in front of the myopic eye reduces its refractive power, rays from distant objects converge in the yellow spot - distance vision improves. The use of glasses, however, inevitably leads to weakening internal muscles eyes, in connection with which, over time, glasses have to be changed to stronger ones.

The ability of the eye to accommodate is examined using the so-called ocular ergography, which makes it possible to accurately determine the degree of visual fatigue. Ergography has also proven to be a valuable method for identifying disorders of dynamic refraction of the eye in myopic children and adolescents; it is used to evaluate the vision of persons engaged in delicate and precise production operations.

Accommodation of the eye is the most important regulator of vision function. With age, its degree gradually decreases, because the lens itself becomes less elastic. A phenomenon called presbyopia, or senile farsightedness, occurs. Due to weakening of accommodation, a person tends to move a book or newspaper away from his eyes (to facilitate the work of the ciliary muscles) or resorts to glasses with convex lenses.

From all that has been said, it is clear how important it is to train the ciliary muscles, as well as the muscles surrounding the eyes, to protect them from premature weakening.

Astigmatism is a distortion of the image by an optical system due to the fact that the refraction or reflection of rays in different sections of the passing light beam is not the same. As a result, the image of the object becomes blurry. Each point of the object is depicted as a blurred ellipse.

The eye is represented here in cross-section. Rays of light enter the pupil through the anterior cornea transparent part outer shell eyes. The cornea is a strong refractive lens. The iris regulates the amount of light entering the eye, which allows you to see in both dim and bright light. The lens focuses light from near and far objects onto the retina. The central fovea of the retina is the area of greatest visual acuity.

Structure of the eye and muscular system

Nature created the eye to be spherical. It easily rotates around three axes: vertical (left - right), horizontal (up - down) and optical. There are three pairs of extraocular muscles located around the eye. Muscles are controlled by signals coming from the brain.

The extraocular muscles are perhaps the fastest-acting muscles in the human body. When inspecting, for example, a painting, the plaza makes a huge number of micro-movements, with one Movement occurring in just a few hundredths of 1 s. In addition, the eye continuously makes small but very fast oscillations (up to 120 volts per second). They are extremely important when examining small objects. As soon as the staring stops, the hesitation disappears. Light wave receiver

When they say about the eye that it is a part of the brain located in the periphery, they mean, first of all, the retina. Essentially, it is an independent analyzer, the first receiver of all its light waves and pulses. It is in the retina of the eye that the processing and transformation of light energy into an electrical impulse occurs, which is sent to the visual centers of the brain.

The structure of the retina is different in different living beings. In vertebrates, from fish to monkeys, and in humans, the light-receiving surface of the eye is an extremely complex neural formation, both in structure and function. The thickness of the retina is very small - 0.14 mm. One of its most important areas is the so-called macula, where vision is best. The macula area contains the bulk of the cone photoreceptors responsible for color vision.

The question of the location of the retina along the axis of the eye is very significant. The fact is that any visual image can be considered as a collection of points. Each of them is fixed on the retina in the form of a point, and due to some optical phenomena (light diffraction, aberration, etc.), its image turns out to be somewhat blurred. As calculations have shown, the retina is located exactly in that place (approximately at a distance of 0.4 mm in front of the focus of the eye) where all optical defects have smallest value. Thanks to this, the clearest vision is achieved.

In the retina of vertebrates, 10 layers of neural elements are usually distinguished, interconnected not only morphologically, but also functionally. The total number of light-perceiving receptors in the retina is 130 million, and only 7 million of them are cone receptors involved in color vision. From each light-sensitive cell - rods or cones - a nerve fiber extends, connecting the receptors to the central nervous system. Moreover, each cone has a separate fiber, while in rods one fiber serves their whole group. The optic nerves cross, and in humans and great apes only half of the fibers of each optic nerve cross. The cerebral, or central end of the visual analyzer is located in the posterior part of the occipital lobe of the cerebral cortex, where the nerve fibers of the center and periphery of the retina converge.

Light is a stream of special particles - photons (quanta). Photons are absorbed and reflected by the substances that make up the objects around us, and the brightness of the visual image we perceive depends on the number of photons. What number of photons penetrates the optical media of the eye and reaches the retina? Special calculations have shown that at dusk or at night (in low light conditions) a very small number of photons penetrate the retina. Into each light-sensitive cell on average in 20 minutes. one photon hits, and in daylight - many.

The question arises: how many of them are required for the retina to enter an excited state, that is, what is the minimum number of photons necessary for the visual process? This issue was studied in detail by Academician S.I. Vavilov and his collaborators. They found that a very small number of photons is sufficient, and in some cases even one is enough. Thus, the sensitivity of the eye to light is extremely high.

"Floors" of vision

The inner surface of the retina is a light-sensitive mosaic. It consists of more than 130 million photoreceptors that perceive and process light - rods and cones, tightly adjacent to each other. Their sizes are extremely small (about 2 microns in diameter); this provides a density of “packing” of nerve elements that is unprecedented even for modern microelectronic technology. Thus, in the macular zone of the human retina there are 140 thousand cones per 1 square meter. mm. In an eagle, the cell density is even greater, and accordingly, visual acuity is higher.

The microscope gives us the opportunity to penetrate inside the photoreceptor. Marvelous! The photoreceptor resembles a skyscraper, with the cone having a sharp spire. Let an imaginary elevator take us from bottom to top along the rod photoreceptor (its length is 50 microns). We will cross numerous “floors” of visual membranes folded into a regular stack, of which there are several thousand in each cell.

Let's stay on one of the floors and take a closer look at its amazing architecture. We see an openwork “architectural ensemble” of fat molecules and light-sensitive proteins, the main one of which is rhodopsin, or visual purple.

Each of the 1 thousand floors of the rod has over 1 thousand membranes (there are about 750 of them in the cone); the floor is a “three-layer cake”, in the middle of which there is a double layer of fat (only 80 angstroms thick), and on top and bottom there are the thinnest layers of rhodopsin (90% of the total amount of protein forming the membrane); its molecular transformations under the influence of light “trigger” the initial stages of the vision process.

Once inside the cone, we would notice that here the visual membranes are in contact with the outer membrane of the cell, which is not the case in the rod. Although the answer to the question of the reasons for the difference in the internal structure of the two types of photoreceptors has not yet been found, it is obvious that it is somehow connected with the difference in their functions: rods have to work at night, when photons hit the retina quite rarely, and the light-sensitive cell becomes excited even when absorbing single photons; the cone, on the contrary, works during the day, in bright sunlight, and it is literally penetrated by an abundant stream of light quanta.

In recent years, English and American scientists have used X-ray diffraction analysis to study the ultrathin structure of visual membranes. He and the results of studies using an electron microscope even revealed the distribution of rhodopsin molecules in the membrane: 90% of their total number is located perpendicular to the long axis of the rods, 10% is parallel. This arrangement ensures maximum light absorption and, consequently, very high sensitivity of the photoreceptor.

Why do photoreceptors need such a multi-story building? As you know, skyscrapers arose due to a lack of space, but what made nature create a mosaic of “skyscrapers” inside the eye? To try to answer this far from easy question, let us turn to molecular mechanisms initial stages process of vision.

The main light-sensitive elements of the retina - rods and cones - consist of outer and inner segments. The outer segments are narrower and elongated, the diameter of the rod is 2 µm, the length is 5 µm, the diameter and length of the cone are slightly smaller. When several quanta of light hit the retina, it is excited, but only 7 out of 10 photons hitting it are able to excite it.

Considering that not all rhodopsin molecules that absorb photons are capable of exciting the membrane, but only those that are directly adjacent to it, English scientists have established that photoreceptor rods are capable of responding to 1 photon absorbed by a molecule lying directly on the membrane. Such hypersensitivity can only be explained by the presence of an amplifying or multiplying mechanism in the photoreceptor itself.

The chemical structure of the visual organs of animals and humans was formed in the process of evolution, as well as under the influence of their lifestyle. Despite all the differences in visual systems, they also have a lot in common, in particular, visual pigments that absorb light and trigger the most complex photochemical mechanism of vision. Pigments play the same role for vision as chlorophyll does for photosynthesis. Chief among them are rhodopsin, the pigment of the retinal rods, and iodopsin, the pigment of the cones. Rhodopsin and iodopsin consist of a chromophore group and a protein - opsin. The region of maximum light absorption for rhodopsin is in the green part of the spectrum (500 nm), for iodopsin - in the yellow-green part (550 nm).

Accordingly, in these same parts of the spectrum, the highest sensitivity of the eye is observed during the day, when cones mainly work, and at night, when rods function.

Under the influence of light, complex photochemical processes occur in rhodopsin and iodopsin, as a result of which some of the molecules of visual pigments disintegrate. Their restoration occurs in the dark with the participation of vitamin A, which is delivered to the receptors via circulatory system eyes.

There are significant differences between rod and cone vision. With the help of cones we distinguish the colors of objects, while rods are responsible for black and white vision.

A person distinguishes an almost infinite number of colors and shades, for which there are not even enough words to define. The most common and most recognized at present is the three-color, or three-component, theory of color vision. All the variety of colors is perceived due to the existence of three types of cones in the retina. Some of them are excited by red rays, others by green, and others by blue-violet, thanks to which we distinguish these three colors. If all types of cones are excited simultaneously and to the same extent, we see white color, but if the excitation of cones different types expressed unequally, there is a feeling of different colors.

Experiments show that any color perceived by the human eye can be obtained by combining red, green and blue-violet colors of different saturations. For example, a mixture of red and yellow gives orange, blue and green - cyan, etc. The laws of optical color mixing also apply when it occurs in the retina.

Various color vision disorders occur in 4% of men and 0.7% of women. This is a lack of perception of red and green colors, a decrease in the ability to perceive green, insensitivity to blue, etc. To determine color vision impairment, special tables have been created that are used when examining railway workers, drivers, etc.

So, the main “character” of the vision process is light. However, biologists and physiologists know that light penetrates through the skin and bones to the central nervous system and causes, in particular, the phenomenon of photoperiodism in birds and other animals whose eyes have been removed. Experiments carried out on visual systems animals, showed that quanta penetrate through the eye and further along the nerve fibers into the visual centers of the brain and can cause direct light irritation of them cellular structures. The proposed hypothesis is called optoelectronic. Its further experimental substantiation is currently underway in a number of laboratories. The fact of the transfer of light quanta from the eye to the brain was confirmed by scientists from the Moscow Medical Dental Institute. Along with photochemical processes, electrical processes also occur in the eye. Information about their progress is used for diagnostics eye diseases. Nowadays, any reputable eye clinic has an electrodiagnostic room. The recorded electrical reaction of the retina to lighting is called an electroretinogram, and its recording and analysis is called electroretinography.

How the organs of vision work.

The cornea and lens focus light rays entering the eye onto the retina. The ciliary muscle changes the thickness of the lens - relaxes or contracts it, so that light coming from different distances - from near and far objects - is focused precisely on the retina. The iris regulates the amount of light entering the eye. Its muscles continually change the diameter of the pupil, increasing it when more light needs to be let in and decreasing it when too much light threatens to damage the retina. The retina contains 2 types of photoreceptors - rods and cones. About 125 million rods provide twilight vision. They are highly sensitive to very weak light, but can only distinguish between black and white. Cones, of which there are about 7 million, provide color vision, but they need bright light to work. There are 3 types of cones depending on the light-sensitive pigment they contain. Some cones detect green, others red, and others blue. Rods and cones generate impulses that are transmitted along the optic nerve to the visual areas of the brain. The brain converts these impulses into an image. Every eye sees the world a little differently. By combining these images, the brain builds a three-dimensional image that allows you to estimate distances and the location of objects in space.

Exercises for vision correction

For the treatment of myopia, the American ophthalmologist W. Bates suggests the following exercises, which he developed after familiarizing himself with the technique of improving the vigilance of the Indians. He determined that the phenomenal vigilance of North American Indians is not a genetic trait, but is developed in early childhood with the help of exercises. Here are some of them.

The head is fixed so that only the eyes can move. In an outstretched hand is a pencil. In wide amplitude it

repeatedly moves to the right, left, down. You have to keep your eyes on him.
Stand against the wall of a large room and, without turning your head, quickly move your gaze from the upper right corner of the room to the lower left, from the upper left to the lower right. Repeat at least 50 times.
Feet shoulder-width apart, hands on the waist. Sharp turns of the head to the right and left. The gaze is directed in the direction of movement. Perform 40 turns.
Look at the bright light for 3 seconds, then close your eyes with your hand and give them rest. Repeat 15 times.
Open your eyes wide, squint hard, close your eyes. Repeat 40 times.
Look out the window at a very distant object and gaze at it for 10 seconds. Look at your wristwatch. Repeat 15 times.

W. Bates recommends performing these and similar exercises 2 times a day. After a month, take a break for 2 - 3 weeks, and then start all over again. This mode of eye work strengthens the eye muscles, trains and massages the lenses, improves blood circulation and nutrition of the eyes.

A set of exercises with a ball to treat myopia

These exercises can be performed both at home and at fresh air. Prepare a place for the lesson: lay out a rug, place a colored object (preferably green or blue color), which you will look at while performing individual exercises. This could be a ball, vase, cup and other objects that are clearly visible without glasses. Count your pulse, turn on the music, grab a volleyball and get started.

Perform exercises using the “Mark on glass” method (see appendix) for 1-2 minutes.

The given complex is designed for 25-30 minutes. After completing the last exercise, count your pulse and take a shower.

Astigmatism

According to the theory of W. Bates, one of the reasons for the occurrence of astigmatism is uneven tension of the periocular muscles.

Astigmatism can be identified using Fig. 2.2. With astigmatism, straight lines appear curved.

Astigmatism is often accompanied by farsightedness or nearsightedness. Since the perception of the shape of the letters on the test card is impaired, the patient quite often names them incorrectly. People with astigmatism often suffer from headaches and have difficulty reading.

R.S. Agarwal considers the following exercise useful for astigmatism.

Do the “Big Turns” exercise 100 times (see appendix). Then move your gaze along the lines of small print with soft blinks on each line. Alternate turns with moving your gaze along the lines.

For astigmatism accompanied by myopia or farsightedness, perform appropriate exercises designed to treat myopia or farsightedness.

Special exercises for the extraocular muscles.

Exercises for the eyes (turns, circular movements, etc.) were part of ancient gymnastic systems. Undoubtedly, they are useful, as they train the muscles that control eye movements, activate blood circulation in this area, and relieve mental fatigue well. After them, people feel much more energetic. In addition, such exercises help get rid of the so-called bags in the area of the lower and upper eyelids (as a rule, this is a sign of aging skin and loss of elasticity). The positive effect is based on certain functional connections between the oculomotor nerve and nerve cells brain vessels.

Here are a few exercises that will help strengthen the extraocular muscles, maintain the elasticity of the skin of the eyelids, and delay its aging (Fig. 2.3). They should be performed for approximately 10 minutes.

Close your eyes tightly and open wide. Repeat the exercise 5-6 times with an interval of 30 s.
Look up, down, right, left without turning your head.
Rotate your eyes: down, right, up, left and in the opposite direction.

Exercises to relieve eye fatigue

Performed standing (Fig. 2.4, a). Look straight ahead for 2-3 seconds. Then place your finger at a distance of 25-30 cm from your eyes, look at the tip of your finger and look at it for 3-5 seconds. Lower your hand. Repeat 10-12 times. The exercise relieves eye fatigue and facilitates visual work at close range. Those who use glasses must perform the exercises without taking them off.
Performed while sitting (Fig. 2.4, b). With three fingers of each hand, lightly press on the upper eyelid, and after 1-2 seconds, remove your fingers. Repeat 3-4 times. Exercise improves the circulation of intraocular fluids.

Relaxation of the vision mechanism

Any tension is relieved by relaxation, i.e. relaxation. Here is what the famous American psychologist D. Carnegie writes about this: “Anxiety, tension and emotional turmoil are the three main causes of fatigue. They are often the ones to blame when physical or mental work seems to be the cause. Remember that a tense muscle never rests. Relax! Save your energy for important things."

Now stop whatever you are doing and check your condition. Are you frowning while reading these lines? Do you feel eye strain? Are you relaxed while sitting in your chair? Or are you hunched over? Are your facial muscles tense? If your body is not relaxed like an old rag doll, then at this very moment you are creating nervous and muscle tension. You are causing yourself nervous tension and nervous fatigue!

Tension is a habit. The ability to relax is a habit. From bad habits can be eliminated and good habits can be created.

How do you relax? Does your brain relax first or your nerves? Neither one nor the other. First of all, your muscles relax!

Now let's try to do this. Perhaps we will start this procedure by relaxing the eyes. Read this paragraph to the end, and then sit back, close your eyes and mentally say to your eyes: “Rest calmly, rest calmly, don’t tense up, don’t frown. Rest, rest peacefully." Repeat these words very slowly for 1 minute.

You probably noticed that after a few seconds the eye muscles began to obey you. Did you feel as if someone's caring hand relieved you of tension? It may seem incredible to you, but in this minute you have found the universal key and the secret to the art of relaxation. You can do the same with the muscles of the face, neck, shoulders and entire body. But the most important organ of all is the eye. Dr. E. Jacobson of the University of Chicago suggested that if you can completely relax your eye muscles, you can forget about all your troubles. The role of the eyes in eliminating nervous tension important because they consume up to one quarter of all the nervous energy of our body. This is why so many people with completely normal vision suffer from rapid eye fatigue - asthenopia. They themselves strain their eyes too much.

You can relax in between almost any time, no matter where you are. Relaxation means the absence of any tension or effort. Think about something pleasant and relaxing. First, let the muscles in your eyes and face relax. Feel how the energy is directed from the facial muscles to the center of your body. Imagine yourself as stress-free as a baby.

Relax whenever possible. Let your body be as pliable as an old sock. When I start work, I put an old maroon sock on my desk. It reminds me of how relaxed I should be. If you don't have a sock, a cat will do. Have you ever picked up a kitten snoozing in the sun? Then you probably noticed that his head and tail hang down like wet newspaper. Yogis advise those who want to master the art of relaxation to imitate a cat. I've never met a tired cat, a cat who had breakdown or suffering from insomnia. The cat is not tormented by anxiety and is not at risk of stomach ulcers. And you, too, can protect yourself from these troubles if you learn to relax like a cat.
Work as hard as you can, but get into a comfortable position. Remember that body tension causes shoulder pain and nervous fatigue.
Check in with yourself 4 or 5 times a day and ask yourself, “Am I trying too hard to do my job? Am I straining muscles that have nothing to do with my work?” This will help you develop the habit of relaxing.
Check in with yourself again at the end of the day by asking yourself, “How tired am I? If I’m tired, it’s not because of mental work, but because of the way it’s done.” “I judge how productively I worked today,” writes D. W. Josselyn, “not by how tired I am, but by how much I am not tired.” He goes on to say, “When I feel particularly tired at the end of the day, or when irritability indicates that my nerves are tired, I know beyond a shadow of a doubt that I have been ineffective that day, both quantitatively and qualitatively.”

Conclusions

Vision is the most powerful source of our knowledge about the external world, one of the most complex, and amazing and beautiful properties of living matter. The eye is a valuable gift of nature.

Excessive information load on the eye and brain today leads to serious disorders and diseases. In developed countries, every fourth person is myopic

One of the main reasons for this growth eye disorders consists of insufficient training, and therefore weakness of the intraocular and periocular muscles.

The above text revealed the main causes of visual impairment. And, also, how to restore it using a special method of optical-motor training, which is based on the dynamic principle.

Eye diseases are divided into congenital, occupational and pathological. Congenital disease is associated with genetic inheritance, occupational disease contributes to modern technology which negatively affect vision. A pathological disease is a serious impairment of vision function. Poor vision is the inability of the eye to adapt to the instinctive physiological act of vision. Currently, there are various types of simulators for training the eye muscles for health purposes (for myopia and farsightedness in adults and children and to reduce visual fatigue) as well as special non-lens and prismatic glasses that can dramatically improve visual acuity without fatigue and, in addition, fight stooping in children.

Exercises for visual relaxation also play an important role, which helps relieve tension and develop tenacity of the eye.

The purpose of the work being performed is to preserve and restore vision with the help of special methodological exercises developed by scientists.

Bibliography

Demirchogliangarant Gurgenovich. Eyes: school of health editor T.N. Prokopyeva. Terra - Sports, Olipia Press, 2000 – 176 p.
Great Encyclopedia of Erudite. Publishing house "Makhaon", 2001.
How to get rid of glasses / M.S Norbekov, -2nd ed., revised. – M.: LLC “Publishing House Astrel”: LLC “Publishing House AST”: CJSC NPP “Ermak”, 2004.

Date: 04/24/2016

Comments: 0

Main types of violations
Symptoms of visual impairment
Observation by an ophthalmologist
Visual impairment: what are the preventive measures?

Man is naturally endowed with five senses that allow him to perceive the world around him. Visual impairment partially deprives him of this opportunity. Depending on its nature, there may be a loss of clarity of perception, color of the image, in some cases the person does not see anything. Visually impaired people are not uncommon these days, and something needs to be done about it.

For many people, vision problems begin in childhood, which is why there is a need for preventive measures and timely adoption of measures to prevent undesirable consequences. Children with visual impairments are often inhibited, indecisive, and their performance at school is noticeably reduced.

Main types of violations

The most common types of visual impairment are:

This classification of disorders is incomplete; it lists defects that can be encountered in life with enough high probability. Eyes can also be injured during active sports and in various everyday situations.

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Symptoms of visual impairment

Children cannot talk about their feelings; at a young age they do not know what vision should be like. in good condition. Some indirect signs should give parents a reason to worry and contact an ophthalmologist:

If at least one of the symptoms appears, you should consult a doctor as soon as possible, showing him the baby.

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Observation by an ophthalmologist

The doctor must conduct an examination based on various tests, the degree of visual acuity, the correct reaction of the eye to stimuli, the ability to focus, and coordinated vision. Specialized equipment allows you to detect strabismus, blurred vision, and astigmatism. After the examination, the doctor prescribes treatment and vision correction using properly selected glasses or contact lenses.

In the future, it is necessary to periodically visit an ophthalmologist to monitor the development of the disease. If the ongoing therapeutic treatment or vision correction is ineffective, the strategy must be changed.

The peculiarity of children is that their body continues to develop. Desynchronization in the development of individual processes can at any moment lead to the appearance of new disorders, so you need to constantly monitor the correct manifestations of the child’s reactions and with great care so as not to miss time.

It is in childhood, due to the mobility of changes, that the probability that existing disorders can be eliminated is quite high.

Over the years, this possibility passes, and the risk that visual impairment in children will persist for life increases. Therefore, you should not delay contacting a specialist, and self-medication is not always advisable.

For visual field impairment, treatment can be quite effective depending on the cause of its occurrence, the qualifications of the doctor and the stage at which it was detected.

Violations and their causes in alphabetical order:

visual impairment -

The most common visual impairments.

Myopia (myopia) (indicated by -): the image of an object is focused depending on the curvature of the cornea along the length of the eyeball. When the cornea is excessively curvature, when the eyeball is elongated, or when both of these symptoms are present, the image is focused not on the retina, but in front of it. Distant objects appear blurry, although the patient can see well up close. People suffering from myopia need glasses to see into the distance. 85% of all people who wear glasses are nearsighted.

Farsightedness (hyperopia) (indicated by a +): This refractive error is caused by insufficient curvature of the cornea, a small eyeball, or both. With farsightedness, the image does not fall on a specific area of the retina, but is located in a plane behind it. Young people with mild farsightedness may not need it at all. optical correction vision. However, at a more mature age, when age-related changes occur in the lens, the patient will need glasses, first in order to see near, and then in order to see at a distance. If a patient suffers from high hyperopia, he will need glasses for both distance and near, even at a young age. 15% of all people who wear glasses are farsighted.

Astigmatism (cylinder) (indicated by angle): its cause is irregular shape cornea, in which its refractive power is unequal, and light rays are refracted at several foci. As a result, a person sees a blurry or distorted image. Almost every person suffers from astigmatism to one degree or another. The name “cylinder” comes from the cylindrical shaped lenses that correct this condition.

Age-related farsightedness (presbyopia) (indicated by a + sign) is a phenomenon that occurs in people over the age of 40. Presbyopia occurs because the lens of the eye becomes less elastic over time, and the muscles that hold it in place weaken. Presbyopic sufferers cannot read and must use reading glasses.

Amblyopia (" lazy eye") is a disease in which visual acuity in one or both eyes is reduced. The main reason for the development of amblyopia is strabismus or another optical disease that completely or partially covers the optical axis (cataracts, drooping eyelids). Because of this, the eye transmits a blurred image to the brain, as a result of which the brain simply suppresses the work of one eye. If amblyopia is left untreated, visual acuity will decrease.

KEY FACTS
- Around the world, about 314 million people suffer from visual impairment, 45 million of them are blind.
- Older people are more likely to suffer from visual impairment. Around the world, women of all ages are at greater risk.
- About 87% of people with visual impairments live in developing countries.
- Number of people who have lost their sight as a result infectious disease, has decreased significantly, but the prevalence of age-related visual impairment is increasing.
- Cataracts remain the leading cause of blindness worldwide, except in the most developed countries.
- Correction of refractive errors can restore normal vision to more than 12 million children (ages 5-15 years).
- Around the world, about 85% of cases of visual impairment are preventable.

Global trends
Since the early 1990s, global trends have shown a decline in the incidence of visual impairment worldwide, as well as a change in causes. Number of cases of visual impairment and blindness caused by infectious diseases, has decreased significantly (indicating the success of international health interventions), but there has been a visible increase in the number of people suffering from blindness or visual impairment due to increasing life expectancy.

What diseases cause visual impairment:

Causes of visual impairment:
The estimated causes of blindness in the world, defined as visual acuity 6/60 or less, are approximately 17 million with cataracts, 6 million with trachoma, 1 million with onchocerciasis and 1 million with xerophthalmia. These conditions are described below. The main causes are age-related optic macular degeneration, glaucoma, senile cataract, optic nerve atrophy, diabetic retinopathy and retinitis pigmentosa.

Degeneration of the optic spot. Age-related degeneration of the optic spot, a small area of the retina that determines the acuity of central vision. Currently, however, laser therapy is used to prevent practical loss of vision in cases where the degeneration process is accompanied by the formation of new retinal vessels.

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