What does pzo mean in ophthalmology? The anterior-posterior size of the eye is normal. Social adaptation of myopic people

Myopia is a relevant clinical and social problem. Among schoolchildren secondary schools 10-20% suffer from myopia. The same incidence of myopia is observed among the adult population, since it occurs mainly in

I. L. Ferfilfain, Doctor of Medical Sciences, Professor, Chief Researcher, Yu. L. Poveshchenko, Candidate of Medical Sciences, Senior Researcher; Research Institute of Medical and Social Problems of Disability, Dnepropetrovsk

Myopia is a pressing clinical and social problem. Among secondary school students, 10-20% suffer from myopia. The same frequency of myopia is observed among the adult population, since it occurs mainly at a young age and does not go away over the years. In Ukraine, in recent years, approximately 2 thousand people are annually recognized as disabled due to myopia and about 6 thousand are registered with medical, social and expert commissions.

Pathogenesis and clinic

The fact of significant prevalence of myopia among the population determines the relevance of the problem. However, the main thing is in different opinions regarding the essence and content of the concept "myopia". Treatment, prevention, professional guidance and suitability, the possibility of hereditary transmission of the disease, and prognosis depend on the interpretation of the pathogenesis and clinical picture of myopia.

The point is that myopia as a biological category is an ambiguous phenomenon: in most cases it is not a disease, but a biological variant of the norm.

All cases of myopia are united by a manifest sign - the optical alignment of the eye. This is a physical category characterized by the fact that with a combination of certain optical parameters of the cornea, lens and the length of the anteroposterior axis of the eye (APA), the main focus of the optical system is located in front of the retina. This optical sign is characteristic of all types of myopia. This optical alignment of the eye may be due to for various reasons: lengthening the anteroposterior axis eyeball or high optical power of the cornea and lens with a normal PZO length.

The initial pathogenetic mechanisms of the formation of myopia have not been sufficiently studied, including hereditary pathology, intrauterine diseases, biochemical and structural changes in the tissues of the eyeball during the growth of the body, etc. The immediate causes of the formation of myopic refraction (pathogenesis) are well known.

The main characteristics of myopia are considered to be a relatively large length of the eyeball PZO and an increase in optical power refractive system of the eyeball.

In all cases of increasing POV, the optical alignment of the eye becomes myopic. The type of myopia determines the following reasons for the increase in the length of the eyeball PZ:

  • the growth of the eyeball is genetically determined (normal variant) - normal, physiological myopia;
  • excessive growth due to the adaptation of the eye to visual work - adaptation (working) myopia;
  • myopia due to a congenital malformation of the shape and size of the eyeball;
  • diseases of the sclera, leading to its stretching and thinning - degenerative myopia.

An increase in the optical power of the refractive system of the eyeball is one of the main characteristics of myopia. This optical alignment of the eye is observed when:

  • congenital keratoconus or phacoconus (anterior or posterior);
  • acquired progressive keratoconus, that is, stretching of the cornea due to its pathology;
  • phacoglobus - acquired spherical shape of the lens due to weakening or rupture of the ciliary ligaments that support its ellipsoidal shape (in Marfan disease or due to injury);
  • temporary change in the shape of the lens due to dysfunction of the ciliary muscle - spasm of accommodation.

Various mechanisms for the formation of myopia determined the pathogenetic classification of myopia, according to which myopia is divided into three groups.

  1. Normal, or physiological, myopia (healthy eyes with myopic refraction) is a variant of a healthy eye.
  2. Conditionally pathological myopia: adaptation (working) and false myopia.
  3. Pathological myopia: degenerative, due to a congenital malformation of the shape and size of the eyeball, congenital and juvenile glaucoma, malformation and disease of the cornea and lens.

Healthy myopic eyes and adaptive myopia are registered in 90-98% of cases. This fact is very important for ophthalmological adolescent practice.

Spasm of accommodation is rare. The opinion that this is common condition, which precedes the onset of true myopia, is recognized by few ophthalmologists. Our experience shows that the diagnosis of “spasm of accommodation” in initial myopia in most cases is the result of a defect in the study.

Pathological types of myopia are serious eye diseases that become common cause low vision and disability occur only in 2-4% of cases.

Differential diagnosis

Physiological myopia in most cases occurs in first grade students and gradually progresses until growth is complete (for girls - up to 18 years, for boys - up to 22 years), but it can stop earlier. Often such myopia is observed in parents (one or both). Normal myopia can reach 7 diopters, but more often it is weak (0.5-3 diopters) or moderate (3.25-6 diopters). At the same time, visual acuity (with glasses) and other visual functions are normal, no pathological changes in the lens, cornea, or membranes of the eyeball are observed. Often, with physiological myopia, there is a weakness of accommodation, which becomes an additional factor in the progression of myopia.

Physiological myopia can be combined with working (adaptive) myopia. The insufficiency of the function of the accommodation apparatus is partly due to the fact that myopic people do not use glasses when working close, and then the accommodation apparatus is inactive, and, as in any physiological system, its functionality is reduced.

Adaptive (working) myopia, as a rule, is weak and less often moderate. Changing the conditions of visual work and restoring the normal volume of accommodation stops its progression.

Accommodation spasm - false myopia - occurs under unfavorable conditions for near visual work. It is diagnosed quite easily: first, the degree of myopia and the amount of accommodation are determined, and by instilling atropine-like substances into the eyes, cycloplegia is achieved - relaxation of the ciliary muscle, which regulates the shape and, consequently, the optical power of the lens. Then the volume of accommodation is re-determined (0-0.5 diopters - complete cycloplegia) and the degree of myopia. The difference between the degree of myopia at the beginning and against the background of cycloplegia will be the magnitude of the spasm of accommodation. This diagnostic procedure is carried out by an ophthalmologist, taking into account the possibility of increased sensitivity of the patient to atropine.

Degenerative myopia is registered in the International Statistical Classification of Diseases ICD-10. Previously, it was defined as dystrophic due to the predominance of dystrophic changes in eye tissue in its clinical manifestations. Some authors call it myopic disease, malignant myopia. Degenerative myopia is relatively rare, occurring in approximately 2-3% of cases. According to Frank B. Thompson, in European countries the frequency of pathological myopia is 1-4.1%. According to N. M. Sergienko, in Ukraine, dystrophic (acquired) myopia occurs in 2% of cases.

Degenerative myopia is a severe form of eyeball disease that can be congenital and often begins in preschool age. Its main feature is a gradual, throughout life, stretching of the sclera of the equatorial and especially the posterior part of the eyeball. The enlargement of the eye along the anteroposterior axis can reach 30-40 mm, and the degree of myopia can be 38-40 diopters. The pathology progresses and after the growth of the body is completed, with the stretching of the sclera, the retina and choroid stretch.

Our clinical and histological studies have revealed significant anatomical changes in the vessels of the eyeball in degenerative myopia at the level of the ciliary arteries, vessels of the circle of Zinn-Haller, which lead to the development of dystrophic changes in the membranes of the eye (including the sclera), hemorrhages, retinal detachment, the formation of atrophic foci, etc. n. It is these manifestations of degenerative myopia that lead to a decrease in visual functions, mainly visual acuity, and disability.

Pathological changes in the fundus of the eye in degenerative myopia depend on the degree of stretching of the membranes of the eye.

Myopia due to a congenital malformation of the shape and size of the eyeball is characterized by an enlargement of the eyeball and, consequently, high myopia at the time of birth. After birth, the course of myopia stabilizes; only slight progression is possible during the child’s growth. Characteristic of such myopia is the absence of signs of stretching of the membranes of the eye and dystrophic changes in the fundus, despite the large size of the eyeball.

Myopia due to congenital or juvenile glaucoma is caused by high intraocular pressure, which causes stretching of the sclera and, therefore, myopia. It is observed in persons young, in whom the formation of the sclera of the eyeball has not yet completed. In adults, glaucoma does not lead to myopia.

Myopia due to congenital malformations and diseases of the cornea and lens is easily diagnosed using a slit lamp (biomicroscopy). It should be remembered that a severe disease of the cornea - progressive keratoconus - may initially manifest itself as mild myopia. The given cases of myopia due to a congenital malformation of the shape and size of the eyeball, cornea and lens are not the only ones of their kind. The monograph by Brian J. Curtin provides a list of 40 types of congenital eye defects accompanied by myopia (as a rule, these are syndromic diseases).

Prevention

Normal myopia, as genetically determined, cannot be prevented. At the same time, eliminating factors that contribute to its formation prevents the rapid progression of myopia. We are talking about intense visual work, poor accommodation, other diseases of the child (scoliosis, chronic systemic diseases), which can influence the course of myopia. Moreover, normal myopia is often combined with adaptive myopia.

Working (adaptive) myopia can be prevented if the factors listed above that contribute to its formation are excluded. In this case, it is advisable to study accommodation in children before school. Schoolchildren with weakened accommodation are at risk of developing myopia. In these cases, accommodation should be restored in full, create optimal conditions for visual work under the supervision of an ophthalmologist.

If myopia is hereditary, then it can be prevented using reproductive medicine methods. This opportunity is very relevant and promising. In approximately half of blind and visually impaired children, severe disabilities are caused by hereditary eye diseases. The living and working conditions of blind and visually impaired people shape vicious circle communication. The likelihood of having children with hereditary pathologies increases sharply. This vicious circle cannot be broken only by educational work among parents who are carriers of hereditary pathology in order to protect their children from a difficult fate. Prevention of hereditary blindness and low vision can be solved by implementing a special national program that would provide genetic counseling and methods of reproductive medicine for the blind and visually impaired - carriers of hereditary pathology.

Treatment

In treatment, as in prevention, the type of myopia is of particular importance.

With normal (physiological) myopia, it is impossible to eliminate the genetically determined parameters of the eyeball and the characteristics of the optical apparatus through treatment. You can only correct the influence of unfavorable factors that contribute to the progression of myopia.

In the treatment of physiological and adaptive myopia, it is advisable to use methods that develop accommodation and prevent its overstrain. To develop accommodation, many methods are used, each of which has no particular advantage. Each optometrist has his own favorite treatment methods.

For myopia due to developmental defects, treatment options are very limited: the shape and size of the eye cannot be changed. The methods of choice are changing the optical power of the cornea ( surgically) and clear lens extraction.

In the treatment of degenerative myopia, there are no methods that can radically affect the process of stretching the eyeball. In this case, refractive surgery and treatment of degenerative processes (medication and laser) are performed. For initial dystrophic changes in the retina, angioprotectors are used (Dicinon, Doxium, Prodectin, Ascorutin); for fresh hemorrhages in the vitreous body or retina - antiplatelet agents (Trental, Tiklid) and hemostatic drugs. To reduce extravasation during wet form For central chorioretinal dystrophy, diuretics and corticosteroids are used. In the phase of reverse development of dystrophies, it is recommended to prescribe absorbable agents (collalizin, fibrinolysin, lekozim), as well as physiotherapeutic treatment: magnetic therapy, electrophoresis, microwave therapy. To prevent peripheral retinal tears, laser and photocoagulation is indicated.

Separately, we should dwell on the issues of treating myopia using scleroplasty methods. In the USA and Western European countries it was abandoned long ago as ineffective. At the same time, scleroplasty has become very widespread in the CIS countries (it is used even in children with physiological or adaptive myopia, in whom it is not associated with stretching of the eyeball, but is the result of body growth). Often the cessation of progression of myopia in children is interpreted as the success of scleroplasty.

Our studies show that scleroplasty is not only useless and illogical for normal and adaptive myopia (namely, these types of myopia in most schoolchildren), but is ineffective for degenerative myopia. In addition, this operation can cause various complications.

Optical correction of myopia

Before carrying out optical correction of myopia, two issues need to be resolved. Firstly, do children with physiological and adaptive myopia need glasses and contact lenses and in what cases? Secondly, what should be the optical correction in patients with high and very high myopia. Doctors often believe that with mild myopia there is no need to wear glasses, since this is a spasm of accommodation, and they make this conclusion without appropriate differential diagnosis. In many cases, glasses are prescribed only for distance vision. These opinions of doctors are not scientifically based. As already noted, weakness of accommodation contributes to the progression of myopia, and weakness of accommodation contributes to working near without glasses. Thus, if a schoolchild with myopia does not use glasses, then its progression will worsen.

Our research and practical experience show that schoolchildren with small and average degree Myopia, it is necessary to prescribe full correction (glasses or contact lenses) for constant wear. This ensures normal function accommodation apparatus, characteristic of a healthy eye.

The issue of optical correction of myopia over 10-12 diopters is a difficult one. With such myopia, patients often cannot tolerate complete correction and, therefore, their visual acuity cannot be fully restored with the help of glasses. Research has shown that, on the one hand, intolerance to spectacle correction is more often observed in people with a weak vestibular apparatus; on the other hand, maximum correction in itself can be the cause of vestibular disorders (Yu. L. Poveshchenko, 2001). Therefore, when prescribing, one should take into account the patient’s subjective sensations and gradually increase the optical power of the glasses. Such patients tolerate contact lenses more easily and provide higher visual acuity.

Social adaptation of myopic people

This question arises when choosing a profession and study, when providing conditions that are harmless to the course of myopia, and finally, in connection with disability.

With normal (physiological) myopia, almost all types are available professional activity with the exception of those where high visual acuity without optical correction is required. It should be taken into account that unfavorable conditions of professional activity can be an additional factor in the progression of myopia. This primarily concerns children and adolescents. IN modern conditions A pressing issue is the mode of operation with computers, which are regulated by special orders of the SES.

With working (adaptive myopia), a wide range of professions are available. However, one should remember what contributes to the formation of this type of myopia: weakness of accommodation, working close to small objects in insufficient lighting and contrast. With normal and adaptive myopia, the problem is not in limiting work activity, but in observing certain conditions visual hygiene.

The issues of social adaptation of persons with pathological myopia are resolved in a fundamentally different way. In case of severe eye diseases, the treatment of which is ineffective, the choice of profession and working conditions is especially important. Among people with pathological myopia, only a third are recognized as disabled. The rest thanks the right choice professional activity and with systematic supportive treatment, they retain a social status almost all their lives, which is certainly more worthy than the status of a disabled person. There are other cases when young people with degenerative myopia take up jobs that do not take into account the state of their vision (as a rule, this is hard unskilled physical labor). Over time, due to the progression of the disease, they lose their jobs, and their opportunity for new employment is extremely limited.

It should be noted that the social well-being of people with pathological myopia largely depends on optical correction, including surgical correction.

In conclusion, I would like to note the following. It is impossible to present all aspects of such a complex problem as myopia in a short article. The main thing that the authors sought to focus on is the following:

  • in treatment, prevention, examination of work capacity is important differential diagnosis type of myopia;
  • There is no need to dramatize the fact of myopia in schoolchildren; with rare exceptions, it is not pathological;
  • degenerative and other types of pathological myopia - severe eye diseases that lead to low vision and disability, require permanent treatment and dispensary observation;
  • Scleroplasty surgery is ineffective and is not recommended for children.

Literature

  1. Avetisov E.S. Myopia. M., Medicine, 1986.
  2. Zolotarev A.V., Stebnev S.D. About some trends in the treatment of myopia over 10 years. Proceedings of the international symposium, 2001, p. 34-35.
  3. Tron E.Zh. Variability of the elements of the optical apparatus of the eye and its significance for the clinic. L., 1947.
  4. Poveshchenko Yu.L. Clinical characteristics of disabling short-sightedness // Medical Perspectives, 1999, No. 3, part 1, p. 66-69.
  5. Poveshchenko Yu.L. Scleroplasty and the possibility of preventing disability due to myopia // Ophthalmological Journal, 1998, No. 1, pp. 16-20.
  6. Poveshchenko Yu.L. Structural changes blood vessels posterior part of the eyeball and sclera in dystrophic myopia//Ophthalmological Journal, 2000, No. 1, p. 66-70.
  7. Ferfilfain I.L. Clinical expert classification of myopia // Ophthalmological Journal, 1974, No. 8, p. 608-614.
  8. Ferfilfain I.L. Disability due to myopia. Clinical and pathogenetic criteria for the examination of work ability: Abstract of the dissertation of doctor of medical sciences, M., 1975, 32 p.
  9. Ferfilfain I.L., Kryzhanovskaya T.V. and others. Severe eye pathology in children and disability//Ophthalmological Journal, No. 4, p. 225-227.
  10. Ferfilfain I.L. On the issue of classification of myopia. Dnipropetrovsk State University, 1999, p. 96-102.
  11. Curtin B. I. The Myopia. 1985.
  12. Frank B. Thompson, M.D. Myopia Surgery (anterior and posterior segments). 1990.

The function of the organs of vision is an important component of the human sensory systems. A decrease in visual acuity significantly affects the quality of life, therefore special attention should be paid when symptoms or suspicion of any pathological processes appear.

The first step is to consult an ophthalmologist. After the examination, the specialist can prescribe a list additional methods examinations to clarify data and make a diagnosis. One such method is eye ultrasound.

Ultrasound examination of the eye (echography) is a manipulation that is based on the penetration and reflection of high-frequency waves from various tissues of the body, followed by the capture of signals by the device’s sensor. The procedure has gained its popularity due to the fact that it is highly informative, safe and painless.

In addition, the method does not require a lot of time and special preliminary preparation. Ultrasound makes it possible to study the structural features of the eye muscles, retina, crystalline, general condition fundus and eye tissues. Often the procedure is prescribed before and after surgical interventions, as well as to make a final diagnosis and monitor the dynamics of the disease.

Indications for ultrasound of the fundus, orbit and orbit

List of indications:

  • myopia (nearsightedness) and hypermetropia (farsightedness) of varying severity;
  • cataract;
  • glaucoma;
  • retinal disinsertion;
  • injuries of various origins and heaviness;
  • pathologies of the fundus and retina;
  • benign and malignant neoplasms;
  • diseases associated with pathology of the eye muscles, blood vessels and nerves, in particular the optic nerve;
  • history hypertension, diabetes mellitus, nephropathy, etc.

In addition to the above, ultrasound of the child’s eyes is also performed for congenital anomalies of the development of the orbits and eyeballs. Since the method has many positive qualities, there are no risks to the child's health.

Ultrasound diagnostics is indispensable in the case of opacity (clouding) of the ocular media, since in this situation it becomes impossible to study the fundus of the eye using other diagnostic methods. In this case, the doctor can perform an ultrasound of the fundus and assess the condition of the structures.

It is worth noting that ultrasound of the eyeball has no contraindications. This diagnostic procedure can be performed on absolutely all people, including pregnant women and children. IN ophthalmological practice To study the structures of the eye, ultrasound is simply a necessary procedure. But there are some situations in which it is recommended to refrain from this type of examination.

Difficulties can arise only in the case of certain types of traumatic injuries to the eye (open wounds of the eyeball and eyelids, bleeding), in which research becomes simply impossible.

How is an ultrasound of the eye done?

The patient is referred by an ophthalmologist for manipulation. Preliminary preparation no need to go through. Patients are advised to remove makeup from the eye area before the ultrasound, as the sensor will be installed on upper eyelid. There are several types of ultrasound examination of the eyeball, depending on the data that needs to be clarified.

Ultrasound diagnostics is based on echolocation and is performed in several special modes. The first is used to measure the size of the orbit, the depth of the anterior chamber, the thickness of the lens, and the length of the optical axis. The second mode is necessary for visualizing the structures of the eyeball. Often, in conjunction with ultrasound echography, Dopplerography is also performed - ultrasonography vessels of the eye.

During the manipulation, the patient takes a sitting or lying position on the couch with his eyes closed. Then the doctor applies a special hypoallergenic gel for ultrasound diagnostics on the upper eyelid and installs the device sensor. In order to better detail the different structures of the eyeball and orbit, the doctor may ask the patient to do some functional tests - eye movements in different sides during the study.

An ultrasound of the eyeball takes about 20–30 minutes. After conducting the examination itself and recording the results, the sonologist fills out a special examination protocol and issues a conclusion to the patient. It must be emphasized that only a specialist doctor of the appropriate category can decipher ultrasound diagnostic data.

Interpretation of the results of an ultrasound examination of the eye

After the examination, the doctor compares and studies the data obtained. Further, depending on the results of the examination, the conclusion is given as normal or pathological. There is a table to check the research results normal values:

  • the lens is transparent;
  • the posterior capsule of the lens is visible;
  • the vitreous body is transparent;
  • eye axis length 22.4–27.3 mm;
  • the refractive power of the eye is 52.6–64.21 diopters;
  • The width of the hypoechoic structure of the optic nerve is 2–2.5 mm.
  • thickness of internal shells 0.7–1 mm;
  • vitreous volume 4 cm3;
  • size anterior-posterior axis the vitreous is 16.5 mm.

Where to do an ultrasound examination of the eye

Today there is a large number of state multidisciplinary and private ophthalmological clinics where you can do ultrasound of the eye orbits. The cost of the procedure depends on the level medical institution, apparatus, specialist qualifications. Therefore, before conducting the study, it is worth taking a responsible approach to choosing an ophthalmologist, as well as the clinic where the patient will be observed.

Ultrasound examination of the eye – advanced diagnostic method, which is based on the principle of echolocation.

The procedure is used to clarify the diagnosis in case of detection of ophthalmological pathologies and determine their quantitative values.

What is eye ultrasound?

Ultrasound of the eyeball and eye orbits allows you to determine localization areas pathological processes, which can be determined due to the reflection of high-frequency waves sent from such areas.

The method is quick and easy to perform and practically complete absence preliminary preparation.

In this case, the ophthalmologist receives the most complete picture of the condition of the tissues of the eye and the fundus of the eye, and can also assess the structure of the muscles of the eye and see abnormalities in the structure of the retina.

This is not only a diagnostic, but also a preventive procedure, which in most cases is performed both after and before surgical interventions in order to assess risks and prescribe optimal treatment.

Indications for use of this method

  • cloudiness of various types;
  • presence in the organs of vision foreign bodies with the ability to determine their exact size and location;
  • neoplasms and tumors of various types;
  • farsightedness and myopia;
  • cataracts;
  • glaucoma;
  • lens luxation;
  • optic nerve pathologies;
  • retinal detachment;
  • adhesions in the tissues of the vitreous body and disturbances in its structure;
  • injuries with the ability to determine their severity and nature;
  • disturbances in the functioning of the eye muscles;
  • any hereditary, acquired and congenital anomalies in the structure of the eyeball;
  • hemorrhages in the eye.

In addition, ultrasound examination makes it possible to determine changes in the characteristics of the optical media of the eye and estimate the size of the orbit.

Ultrasound also helps to measure the thickness of fatty tissue and its composition, which is necessary information when differentiating forms of exophthalmos (“bulging eyes”).

Contraindications

  • open injuries of the eyeball with violation of the integrity of its surface;
  • hemorrhages in the retrobulbar area;
  • any damage to the eye area (including eyelid injuries).

What does an ultrasound of the eye show: what pathologies can be detected

Ultrasound of the eye shows many ophthalmological diseases, in particular, it is possible to diagnose diseases such as refractive errors (farsightedness, myopia, astigmatism), glaucoma, cataracts, pathologies of the optic nerve, degenerative processes of the retina, the presence of tumors and neoplasms.

Also, through the procedure, you can monitor the conditions of pathologies during treatment, as well as any ophthalmological inflammatory processes and pathological changes in lens tissue.

How is an ultrasound of the eye done?

In modern ophthalmological practice, several types of ultrasound examination are used, each of which is designed to perform specific tasks and is done using its own technical features:

In B-mode, no anesthesia is required, since the specialist moves the sensor over the eyelid closed eye, and to ensure normal conduct During the procedure, it is enough to lubricate the eyelid with a special gel, which will facilitate such sliding.

Normal indicators of a healthy eye during ultrasound

After the ultrasound procedure, the specialist passes the completed patient card to the attending physician, who deciphers the readings.

Normal indications for the procedure are:

Useful video

This video shows an ultrasound of the eye:

Minor deviations of these characteristics are acceptable, but if the values ​​go far beyond such indicators, this is a reason to undergo additional examinations in order to confirm the disease and prescribe adequate treatment to the patient.

Causes of myopia

Today this phenomenon occurs very often. Statistics show that about a billion people around the world suffer from myopia. Ophthalmologists diagnose it at any age. However, it is first discovered in children aged 7 to 12 years, and the disease intensifies during adolescence. Between the ages of 18 and 40, visual acuity usually stabilizes. So, let's learn about the causes of myopia.

Briefly about the disease

The second name for the disease used by doctors is myopia. It is a visual impairment in which the patient sees close objects perfectly and poorly those that are at a distance. The term “myopia” was introduced by Aristotle, who noticed that people who have poor distance vision squint their eyes.

Speaking in the language of ophthalmologists, myopia is a pathology of eye refraction, when the image of objects appears in front of the retina. In such people, the length of the eye is increased or the cornea has a high refractive power. This is why refractive myopia occurs. Practice shows that most often these two pathologies are combined. With myopia, visual acuity decreases.

Myopia is classified into strong, weak, and moderate.

Why does myopia occur?

Ophthalmologists name several reasons for the development of myopia. Here are the main ones:

  1. Irregular shape of the eyeball. In this case, the length of the anteroposterior axis of the organ of vision is greater than normal, and when focusing, light rays simply do not reach the retina. The elongated shape of the eyeball is a stretch back wall eyes. This state of the vision system can change the fundus of the eye, for example, contribute to retinal detachment, myopic cone, and dystrophic disorders in the macular zone.
  2. Excessive refraction of light rays by the optical eye system. The size of the eye corresponds to the norm, however, strong refraction causes light rays to converge in focus in front of the retina, and not traditionally on it.

In addition to these causes of myopia, ophthalmologists also identify factors that contribute to the development of this eye disease. These are the following circumstances:

  1. Genetic predisposition. Experts in the field of ophthalmology state that people do not inherit poor eyesight, but a physiological tendency towards it. And the first at risk are those patients whose father and mother are myopic. If only one of the parents has myopia, then the chances of their son or daughter developing the disease are reduced by 30 percent.
  2. Weakening of the scleral tissue often increases the size of the eyeball under the influence of increased intraocular pressure. The consequence of this is the development of myopia in a person.
  3. Weakness of accommodation, which leads to stretching of the eyeball.
  4. General weakening of the body as the basis for the formation of myopia. It is often the result of both overwork and poor nutrition.
  5. The presence of allergic and infectious diseases in the body (diphtheria, scarlet fever, measles, hepatitis).
  6. Birth and brain injuries.
  7. Diseases of the nasopharynx and oral cavity in the form of tonsillitis, adenoids, sinusitis.
  8. Unfavorable operating conditions visual system. Ophthalmologists include excessive strain on the eyes and their overstrain; reading in moving vehicles, in the dark, in a lying position; sitting for many hours without breaks in front of a computer or TV screen; poor workplace lighting; incorrect posture while writing and reading.

All of the above reasons and factors, especially a combination of several of them, contribute to the development of myopia in children and adults.

Purpose: to study the dynamics of PZO taking into account the refraction of healthy eyes in healthy children aged 1 month and older. up to 7 years and compare with PZO of eyes with congenital glaucoma in children of the same age.
Material and methods: studies were conducted on 132 eyes with congenital glaucoma and 322 healthy eyes. By age, children with congenital glaucoma and with healthy eyes were distributed according to the classification of E.S. Avetisova (2003). Thus, there were 30 newborns (55 eyes) with glaucoma, 25 children under 1 year old (46 eyes), and 55 children under 3 years old (31 eyes). Among the subjects with healthy eyes: newborns - 30 eyes, up to 1 year - 25 eyes, up to 3 years - 55 eyes, 4-6 years - 111 eyes, 7-14 years - 101 eyes. The following research methods were used: tonometry, Nesterov tonography and elastotonometry, biomicroscopy, gonioscopy, ophthalmoscopy, A/B scanning using the ODM-2100 Ultrasonik A/B scanner for orthalmology.
Results and conclusions: having studied the normal PZO of the eyes at different age periods, we identified a significant range of fluctuations in the PZO indicators, the extreme values ​​of which may correspond to pathological ones. An increase in the size of the anterior-posterior axis of the eye in congenital glaucoma depends not only on a violation of the hemohydrodynamic processes of the eye with the accumulation intraocular fluid, but also on the age-related dynamics of pathological eye growth and the degree of refraction.
Key words: anterior-posterior axis of the eye, congenital glaucoma.

Abstract
Comparative analysis of the anterior-posterior axes of eyes of patients with congenital glaucoma and healthy
patients taking into consideration of the age aspect
Yu.A. Khamroeva, B.T. Buzrukov

Pediatric medical institute, Tashkent, Uzbekistan
Purpose: To study the dynamics of the APA in healthy children taking into consideration the refraction of healthy eyes aged from one month to seven years, compared to APA of patients with congenital glaucoma of the same age.
Methods: The study was performed on 132 eyes with congenital glaucoma and 322 of healthy eyes. Patients with congenital glaucoma and healthy subjects were distributed by age according to the classification of E.S. Avetisov (2003), 30 newborns (55 eyes), 25 patients under 1 year old (46 eyes) of, 55 healthy patients under 3 years old, (31 eyes) and newborns (30 eyes), under 1 year (25 eyes) , under 3 years (55 eyes), 4-6 years old (111 eyes), from 7 to 14 years old (101 eyes). Tonometry, tonography, elastotonometry, biomicroscopy, gonioscopy, ophthalmoscopy, A/B scanning were performed.
Results and conclusion: there were significant amplitude of the APAindices revealed in patients of various ages. The extreme values ​​may indicate the pathology. Increase of APA size in congenital glaucoma depends not only on a disparity of hydrodynamic processes but also on age dynamics of eye growth and refraction.
Key words: anterior-posterior axis (APA) of the eye, congenital glaucoma.

Introduction
It has now been established that the main trigger for the development of the glaucomatous process is an increase in intraocular pressure (IOP) to a level above the target. IOP is an important physiological constant of the eye. Several types of IOP regulation are known. At the same time, the exact indicators of IOP, especially in children, are influenced by several anatomical and physiological factors, the main of which are the volume of the eye and the size of its anterior-posterior axis (APA). Research recent years show that one of the key factors in the development of glaucomatous lesions may be a change in the biomechanical stability of the connective tissue structures of the eye, not only in the area of ​​the optic nerve head (OND), but also the fibrous capsule as a whole. This statement is supported by the gradual thinning of the sclera and cornea.
Purpose: to study the dynamics of PZO taking into account the refraction of healthy eyes in healthy children aged 1 month and older. up to 7 years and compare with PZO of eyes with congenital glaucoma in children of the same age.
Material and methods
The studies were conducted on 132 eyes with congenital glaucoma and 322 healthy eyes. Children were distributed by age according to the classification of E.S. Avetisova (2003): with congenital glaucoma: newborns - 30 patients (55 eyes), up to 1 year - 25 (46 eyes), up to 3 years - 55 (31 eyes); children with healthy eyes: newborns - 30 eyes, up to 1 year - 25 eyes, up to 3 years - 55 eyes, 4-6 years - 111 eyes, 7-14 years - 101 eyes.
The following research methods were used: tonometry, Nesterov tonography and elastotonometry, biomicroscopy, gonioscopy, ophthalmoscopy. A/B scanning on the ODM-2100 Ultrasonik A/C scanner for opfhthalmology. According to the stages of the disease and age, patients with congenital glaucoma were distributed as follows (Table 1).
Results and discussion
Despite the fact that there is data on the average values ​​of the anatomical and optical elements of healthy eyes, including the anterior-posterior axis of the eyes (APA) at the age from newborn to 25 years (Avetisov E.S., et al., 1987) and from newborns up to 14 years of age (Avetisov E.S., 2003, Table 2), such studies have not previously been conducted in the Republic of Uzbekistan. Therefore, it was decided to perform echobiometric studies of PZO indicators on 322 healthy eyes in children aged from 1 month. up to 7 years, taking into account the degree of refraction of the eye and compare the data obtained with the results of similar studies on eyes with congenital glaucoma (132 eyes) in children of the same age. The research results are presented in Table 3.
PZO indicators are normal in almost all age groups, except for newborns, practically coincided with the data given in the table by E.S. Avetisova (2003).
Table 4 presents data on PZO of normal eyes depending on refraction and age.
The relative dependence of the degree of refraction on the shortening of the eye's PZO was noted only from 2 years of age (by 1.8-1.9 mm).
It is known that when studying IOP in eyes with congenital glaucoma, difficulties arise in determining how much this IOP characterizes normal hydrodynamic processes or their pathology. This is due to the fact that in young children the membranes of the eyes are soft and easily extensible. As intraocular fluid accumulates, they stretch, the eye increases in volume, and IOP remains within normal values. However, this process leads to metabolic disorders, damaging the fibers of the optic nerve and worsening metabolic processes in ganglion cells. In addition, it is necessary to clearly differentiate between pathological and natural age-related growth of the child’s eyes.
Having studied normal indicators PZO of the eyes in different age periods, we found that the extreme values ​​of these indicators may correspond to the values ​​​​in pathology. In order to clearly determine whether the stretching of the eyeball is pathological, we simultaneously analyzed the relationship of PZO indicators with IOP, refraction, the presence of glaucomatous excavation, its size and depth, the horizontal size of the cornea and its limbus.
Thus, at an advanced stage of the disease in 10 eyes of newborns with POV = 21 mm, the tonometric pressure (Pt) was 23.7 ± 1.6 mm Hg. Art. (p≤0.05), disc excavation - 0.3±0.02 (p≤0.05); in children under 1 year of age (36 eyes) with PPV = 22 mm Pt was equal to 26.2 ± 0.68 mm Hg. Art. (p≤0.05), disc excavation - 0.35±0.3 (p≤0.05). In children under 3 years of age (10 eyes) with PPV = 23.5 mm Pt reached 24.8 ± 1.5 mm Hg. Art. (p≥0.05), disc excavation - 0.36±0.1 (p≤0.05). The size of the eye PZ exceeded the average statistical norm by 2.9, 2.3 and 2.3 mm, respectively, in each age group.
In cases of advanced stage glaucoma in children under 1 year of age (45 eyes), the PZ size was 24.5 mm, Pt - 28.0±0.6 mm Hg. Art. (p≤0.05), disc excavation - 0.5±0.04 (p≤0.05), in children under 2 years of age (10 eyes) with PZO 26 mm Pt reached 30.0±1.3 mm Hg . Art. (p≤0.05), disc excavation - 0.4±0.1 (p≤0.05). In children under 3 years of age (11 eyes), with a POV of 27.5 mm, Pt was equal to 29 ± 1.1 mm Hg. Art. (p≤0.05), disc excavation - 0.6±0.005 (p≤0.05). In the terminal stage (10 eyes) with a PPV of 28.7 mm, Pt was 32.0 ± 1.2 mm Hg. Art. (p≥0.05), disc excavation - 0.9±0.04 (p≤0.05). In these children, the size of the eye PZ exceeded the average statistical norm by 4.7, 4.8, 6.3 mm, and in the terminal stage - by 7.5 mm.

conclusions
1. An increase in the size of the PZO of the eye in congenital glaucoma depends not only on the disruption of hemohydrodynamic processes of the eye with the accumulation of intraocular fluid, but also on the age-related dynamics of pathological growth of the eye and the degree of refraction.
2. Diagnosis of congenital glaucoma should be based on examination data, such as the results of echobiometry, gonioscopy, IOP, taking into account the rigidity of the fibrous membrane of the eye and incipient glaucomatous optic neuropathy.






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Currently, a large number of formulas have been developed for accurately calculating the optical power of an implanted intraocular lens (IOL). All of them take into account the value of the anteroposterior axis (APA) of the eyeball.

The contact method of one-dimensional echography (A-method) is widely used in ophthalmological practice for studying the eyeball PZO, however, its accuracy is limited by the resolution of the device (0.2 mm). In addition, incorrect position and excessive pressure of the sensor on the cornea can lead to significant errors in measuring the biometric parameters of the eye.

The optical coherent biometry (OCB) method, in contrast to the contact A-method, allows one to measure the PZO with higher accuracy and then calculate the optical power of the IOL.

The resolution of this technique is 0.01-0.02 mm.

Currently, along with OCB, ultrasonic immersion biometry is a highly informative method for measuring PZO. Its resolution is 0.15 mm.

An integral part of the immersion technique is immersing the sensor in an immersion medium, which eliminates direct contact of the sensor with the cornea and, therefore, increases the accuracy of measurements.

J. Landers showed that partial coherent interferometry carried out using the IOLMaster device allows one to obtain more accurate results than immersion biometry, however, J. Narvaez and co-authors in their study did not obtain significant differences between the biometric parameters of the eyes measured by these methods.

Target- comparative assessment of eye POV measurements using IB and OCB to calculate IOL optical power in patients with age-related cataracts.

Material and methods. 12 patients (22 eyes) with cataracts aged from 56 to 73 years were examined. Average age of patients was 63.8±5.6 years. In 2 patients, mature cataracts were diagnosed in one eye (2 eyes), and immature cataracts were diagnosed in the paired eye (2 eyes); 8 patients had immature cataracts in both eyes; 2 patients had initial cataract in one eye (2 eyes). The fellow eyes were not examined in 2 patients due to pathological changes in the cornea (post-traumatic corneal cataract - 1 eye, opacification of the corneal graft - 1 eye).

Besides traditional methods studies including visometry, refractometry, tonometry, biomicroscopy of the anterior segment of the eye, biomicroophthalmoscopy; all patients underwent an ultrasound examination of the eye, including A- and B-scanning using the NIDEK US-4000 echo scanner. To calculate the optical power of the IOL, the PZO was measured using the IB on the Accutome A-scan synergy device and the OKB on the IOLMaster 500 (Carl Zeiss) and AL-Scan (NIDEK) devices.

Results and discussion. PPV ranging from 22.0 to 25.0 mm was recorded in 11 patients (20 eyes). In one patient (2 eyes), the POV in the right eye was 26.39 mm, in the left eye - 26.44 mm. Using the ultrasound IB method, it was possible to measure PZO in all patients, regardless of the density of the cataract. In 4 patients (2 eyes - mature cataract, 2 eyes - localization of opacities under the posterior capsule of the lens) during OCB using the IOLMaster device, PZO data were not determined due to high density lens opacities and insufficient visual acuity of patients to fix their gaze. When performing OCB using the AL-Scan device, PZO was not recorded only in 2 patients with posterior capsular cataract.

A comparative analysis of the results of a study of the biometric parameters of the eyes showed that the difference between the PPV indicators measured using IOL-Master and AL-scan ranged from 0 to 0.01 mm (on average - 0.014 mm); IOL-Master and IB - from 0.06 to 0.09 mm (average - 0.07 mm); AL-scan and IB - from 0.04 to 0.11 mm (average - 0.068 mm). The IOL calculation data based on the results of measuring the biometric parameters of the eye using OCB and ultrasound IB were identical.

In addition, the difference in anterior chamber (ACD) measurements between the IOL-Master and AL-scan ranged from 0.01 to 0.34 mm (mean 0.103 mm).

When measuring horizontal corneal diameter (white to white or WTW), the difference in values ​​between the IOL-Master and AL-scan devices ranged from 0.1 to 0.9 mm (average 0.33), with WTW and ACDs were higher on AL-scan compared to IOLMaster.

It was not possible to compare the keratometric indicators obtained on the IOL-Master and AL-scan, since these measurements are carried out in different parts of the cornea: on the IOLMaster - at a distance of 3.0 mm from the optical center of the cornea, on the AL-scan - in two zones : at a distance of 2.4 and 3.3 mm from the optical center of the cornea. The data for calculating the optical power of the IOL based on the results of measuring the biometric parameters of the eye using OCB and ultrasound immersion biometry coincided, with the exception of cases of high myopia. It should be noted that the use of AL-scan made it possible to measure biometric indicators in 3D control mode over the patient’s eye movements, which certainly increases the information content of the results obtained.

conclusions.

1. The results of our study showed that the difference in PZO measurements using IS and OCB is minimal.

2. When performing immersion biometry, the PZ values ​​were determined in all patients, regardless of the degree of cataract maturity. The use of AL-scan, in contrast to IOLMaster, makes it possible to obtain PZO data for denser cataracts.

3. There were no significant differences between biometric parameters and IOL optical power indicators obtained using IB and OKB.

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