Currently, a large number of formulas have been developed for the accurate calculation of the optical power of an implantable intraocular lens (IOL). All of them take into account the value of the anteroposterior axis (PZO) of the eyeball.

The contact method of one-dimensional echography (A-method) is widespread in ophthalmic practice for examining the PZO of the eyeball, 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 the measurements of the biometric parameters of the eye.

The method of optical coherent biometry (OCB), in contrast to the contact A-method, makes it possible to measure PZO with a higher accuracy with the subsequent calculation of the optical power of the IOL.

The resolution of this technique is 0.01-0.02 mm.

Currently, along with the OKB, 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 immersion of the sensor in an immersion environment, which excludes direct contact of the sensor with the cornea and, therefore, increases the measurement accuracy.

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

goal - Comparative assessment of measurements of the PZO of the eye using IB and OKB for calculating the optical power of the IOL in patients with age-related cataract.

Material and methods... The study involved 12 patients (22 eyes) with cataracts at the age from 56 to 73 years. The average age of the patients was 63.8 ± 5.6 years. In 2 patients, mature cataract (2 eyes) was diagnosed in one eye, immature cataract in the paired one (2 eyes); in 8 patients - immature cataract in both eyes; 2 patients had an initial cataract in one eye (2 eyes). The study of paired eyes in 2 patients was not carried out due to pathological changes in the cornea (post-traumatic corneal leucorrhoea - 1 eye, opacity of the corneal graft - 1 eye).

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

Results and discussion... PZO in the range from 22.0 to 25.0 mm was registered in 11 patients (20 eyes). In one patient (2 eyes), the PZO in the right eye was 26.39 mm, on the left - 26.44 mm. Using the method of ultrasound IB, PZO was able to measure 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 OKB using the IOLMaster device, PZO data were not determined due to the high density of lens opacities and insufficient visual acuity of patients to fix the gaze. When performing OKB using the AL-Scan device, PZO was not recorded only in 2 patients with posterior capsular cataract.

Comparative analysis of the results of the study of biometric parameters of the eyes showed that the difference between the PZO parameters measured using the 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 (on average - 0.07 mm); AL-scan and IB - from 0.04 to 0.11 mm (on average - 0.068 mm). The data of the IOL calculation based on the results of measurements of the biometric parameters of the eye using the OKB and the ultrasonic IB were identical.

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

When measuring the horizontal diameter of the cornea (parameter "from white to white" or WTW), the difference in values \u200b\u200bbetween the IOL-Master and AL-scan devices ranged from 0.1 to 0.9 mm (0.33 on average), and the WTW and ACDs were higher on AL-scan compared to IOLMaster.

It was not possible to compare the keratometric parameters 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 AL-scan - in two zones : at a distance of 2.4 and 3.3 mm from the optical center of the cornea. The data of calculating the optical power of the IOL based on the results of measurements of the biometric parameters of the eye using the OKB and ultrasound immersion biometry coincided, except for cases of high myopia. It should be noted that the use of AL-scan made it possible to measure biometric indicators in the 3D control mode of the patient's eye movements, which undoubtedly increases the information content of the results obtained.

conclusions.

1. The results of our research have shown that the difference in the measurements of PZO with the help of IB and OKB is minimal.

2. When carrying out immersion biometry, the values \u200b\u200bof PZO were determined in all patients, regardless of the degree of maturity of the cataract. The use of AL-scan, in contrast to the IOLMaster, allows obtaining PZO data for denser cataracts.

3. There were no significant differences between biometric parameters, IOL optical power indices obtained with the help of IB and OKB.

The eyeball tissue is a collection of acoustically dissimilar media. When an ultrasonic wave hits the interface between two media, it is refracted and reflected. The more the acoustic impedances (impedances) of the boundary media differ, the more part of the incident wave is reflected. The determination of the topography of normal and pathologically altered biological media is based on the phenomenon of reflection of ultrasonic waves.

Ultrasound is used to diagnose in vivo measurements of the eyeball and its anatomical and optical elements. This is a highly informative instrumental method, an addition to the generally recognized clinical methods of ophthalmic diagnostics. As a rule, echography should be preceded by a traditional anamnestic and clinical ophthalmological examination of the patient.

The study of echobiometric (linear and angular values) and anatomical and topographic (localization, density) characteristics is carried out according to the main indications. These include the following.

• The need to measure the thickness of the cornea, the depth of the anterior and posterior chambers, the thickness of the lens and inner membranes of the eye, the length of the CT, various other intraocular distances and the size of the eye as a whole (for example, with foreign bodies in the eye, subatrophy of the eyeball, glaucoma, myopia, when calculating the optical strength of intraocular lenses (IOL)).
• Study of the topography and structure of the anterior chamber angle (APC). Assessment of the state of the surgically formed outflow tract and UPC after antiglaucoma interventions.
• IOL position assessment (fixation, dislocation, adhesion).
• Measurement of the length of retrobulbar tissues in various directions, the thickness of the optic nerve and rectus muscles of the eye.
• Determination of the magnitude and study of the topography of pathological changes, including eye neoplasms, retrobulbar space; quantitative assessment of these changes in dynamics. Differentiation of various clinical forms of exophthalmos.
• Assessment of the height and prevalence of detachment of the ciliary body, choroid and retinal membranes of the eye in difficult ophthalmoscopy.
• Identification of destruction, exudate, opacities, blood clots, moorings in CT, determination of the peculiarities of their localization, density and mobility
• Identification and determination of the localization of intraocular foreign bodies, including clinically invisible and X-ray-negative, as well as assessment of the degree of their encapsulation and mobility, magnetic properties.

Principle of operation

Echographic examination of the eye is carried out by contact or immersion methods.

Contact method

Contact one-dimensional echography is performed as follows. The patient is seated in a chair to the left and somewhat in front of the diagnostic ultrasound device, facing the doctor, who is sitting in front of the screen of the device halfway to the patient. In some cases, an ultrasound scan is possible when the patient is lying on the couch, face up (the doctor is located at the head of the patient).

Before examination, an anesthetic is instilled into the conjunctival cavity of the examined eye. With his right hand, the doctor brings an ultrasonic probe sterilized with 96% ethanol into contact with the patient's eye being examined, and with his left hand he regulates the operation of the device. The contact medium is lacrimal fluid.

An acoustic examination of the eye begins with a survey using a probe with a 5 mm piezoplate diameter, and the final conclusion is given after a detailed examination using a probe with a 3 mm piezoplate diameter.

Immersion method

The immersion method of acoustic examination of the eye assumes the presence of a layer of liquid or gel between the piezoplate of the diagnostic probe and the examined eye. Most often, this method is implemented using ultrasound equipment, which is mainly based on the B-method of echography. A diagnostic probe scanning along a different trajectory "floats" in an immersion medium (degassed water, isotonic sodium chloride solution) located in a special attachment that is installed on the subject's eye. The diagnostic probe can also be housed in a sheath with a sound-transparent membrane that is brought into contact with the patient's closed eyelids while seated in the chair. Instillation anesthesia is not needed in this case.

Research methodology

• One-dimensional echography (A-method) - a fairly accurate method that allows you to graphically identify various pathological changes and formations, as well as measure the size of the eyeball and its individual anatomical and optical elements and structures. The method has been modified into a separate special direction - ultrasound biometrics.
• Two-dimensional echography (acoustic scanning, B-method)- based on the conversion of the amplitude gradation of echo signals into light points of various degrees of brightness, forming an image of the cross section of the eyeball on the monitor.
• UBM... Digital technologies have made it possible to develop a UBM method based on digital analysis of the signal of each piezoelectric element of the sensor. The UBM resolution at the axial scanning plane is 40 µm. For this resolution, 50-80 MHz sensors are used.
• 3D echography... Three-dimensional echography reproduces a volumetric image when adding and analyzing multiple planar echograms or volumes during the movement of the scanning plane vertically-horizontally or concentrically around its central axis. Obtaining a volumetric image occurs either in real time (interactive) or delayed, depending on the sensors and processor power.
• Power Doppler (energy Doppler mapping) - a method of blood flow analysis, consists in displaying numerous amplitude and velocity characteristics of erythrocytes, the so-called energy profiles.
• Pulsed Wave Doppler allows you to objectively judge the speed and direction of blood flow in a particular vessel, to investigate the nature of the noise.
• Duplex ultrasound examination.Combining pulsed Doppler and scanning in gray scale mode in one device allows simultaneous assessment of the state of the vascular wall and registration of hemodynamic parameters. The main criterion for assessing hemodynamics is the linear blood flow velocity (cm / s).

The algorithm for acoustic examination of the eye and orbit consists in the consistent application of the principle of complementarity (complementarity) of survey, localization, kinetic and quantitative echography.

• Plain echography is performed to reveal asymmetry and a focus of pathology.
• Localization echography allows using echobiometry to measure various linear and angular parameters of intraocular structures and formations and determine their anatomical and topographic relationships.
• Kinetic echography consists of a series of repeated ultrasounds after rapid eye movements of the subject (changing the direction of the patient's gaze). The kinetic test allows you to establish the degree of mobility of the detected formations.
• Quantitative echography gives an indirect idea of \u200b\u200bthe acoustic density of the studied structures, expressed in decibels. The principle is based on a gradual reduction of echo signals until they are completely canceled.

The task of preliminary ultrasound is to visualize the main anatomical and topographic structures of the eye and orbit. For this purpose, in the gray scale mode, scanning is carried out in two planes:

• horizontal (axial), passing through the cornea, eyeball, internal and external rectus muscles, optic nerve and the apex of the orbit;
• vertical (sagittal), passing through the eyeball, superior and inferior rectus muscles, optic nerve and the apex of the orbit.

A prerequisite for providing the greatest informational value of ultrasound is the orientation of the probe at a right (or close to right) angle to the structure (surface) under study. In this case, an echo signal of maximum amplitude is recorded coming from the object under study. The probe itself should not exert pressure on the eyeball.

When examining the eyeball, it is necessary to remember about its conditional division into four quadrants (segments): upper and lower external, upper and lower internal. The central zone of the fundus with the optic nerve disc and the macular region located in it is especially distinguished.

Characteristics in health and disease

When passing the scanning plane approximately along the anteroposterior axis of the eye, echo signals are received from the eyelids, cornea, anterior and posterior surfaces of the lens, and the retina. The transparent lens is not acoustically detected. Its posterior capsule is visualized more clearly in the form of a hyperechoic arc. CT is normal, acoustically transparent.

When scanned, the retina, choroid and sclera virtually merge into a single complex. In this case, the inner shells (reticular and vascular) have a slightly lower acoustic density than the hyperechoic sclera, and their thickness together is 0.7-1.0 mm.

In the same scanning plane, a funnel-shaped retrobulbar part is visible, limited by hyperechoic bony walls of the orbit and filled with fine-grained fatty tissue of medium or slightly increased acoustic density. In the central zone of the retrobulbar space (closer to the nasal part), the optic nerve is visualized as a hypoechoic tubular structure about 2.0-2.5 mm wide, emanating from the eyeball from the nasal side at a distance of 4 mm from its posterior pole.

With the appropriate orientation of the sensor, the plane of scanning and the direction of gaze, an image of the rectus muscles of the eye is obtained in the form of homogeneous tubular structures with a lower acoustic density than adipose tissue, with a thickness of 4.0-5.0 mm between fascial sheets.

With subluxation of the lens, a different degree of displacement of one of its equatorial edges in the PT is observed. In case of dislocation, the lens is detected in various layers of the CT or in the fundus. During the kinetic test, the lens either moves freely or remains fixed to the retina or CT fibrous cords. With aphakia, during ultrasound, the iris that has lost its support is observed to tremble.

When replacing the lens with an artificial IOL, a high acoustic density formation is visualized behind the iris.

In recent years, great importance has been attached to the echographic study of the structures of the CPC and the iridociiliary zone as a whole. With the help of UBM, three main anatomical and topographic types of the structure of the iridociliary zone were identified, depending on the type of clinical refraction.

• The hyperopic type is characterized by a convex iris profile, a small iridocorneal angle (17 ± 4.05 °), a characteristic anteromedial attachment of the iris root to the ciliary body, providing a coracoid shape of the UPC with a narrow entrance (0.12 mm) into the corner bay and a very close location of the iris with trabecular zone. With this anatomical and topographic type, favorable conditions arise for the mechanical blockade of the CPC by the iris tissue.
• Myopic eyes with an inverse iris profile, iridocorneal angle (36.2 + 5.25 °), a large contact area of \u200b\u200bthe pigment layer of the iris with the zinn ligaments and the anterior surface of the lens have a predisposition to the development of pigmented dispersed syndrome.
• Emmetropic eyes are the most common type, characterized by a straight iris profile with an average value of the UPK 31.13 ± 6.24 °, a depth of the posterior chamber 0.56 ± 0.09 mm, a relatively wide entrance to the bay of the UPK - 0.39 ± 0, 08 mm, front-rear axle - 23.92 + 1.62 mm. With this design of the iridociliary zone, there is no obvious predisposition to hydrodynamic disturbances, i.e. there are no anatomical and topographic conditions for the development of pupillary block and pigmented-dispersed syndrome.

Changes in the acoustic characteristics of ST arises due to degenerative-dystrophic, inflammatory processes, hemorrhages, etc. Opacities can be floating and fixed; dotted, filmy, in the form of lumps and conglomerates. The degree of opacity varies from subtle to coarse moorings and pronounced continuous fibrosis.

When interpreting ultrasound data hemophthalmos you should remember about the stages of its course

• Stage I - corresponds to the processes of hemostasis (2-3 days from the moment of hemorrhage) and is characterized by the presence of coagulated blood in the CT of moderate acoustic density.
• Stage II - the stage of hemolysis and diffusion of hemorrhage, accompanied by a decrease in its acoustic density, blurring of the contours. In the process of resorption, against the background of hemolysis and fibrinolysis, a fine-point suspension appears, often delimited from the unchanged part of the CT by a thin film. In some cases, at the stage of hemolysis of erythrocytes, ultrasound is not informative, since the blood elements are proportional to the ultrasound wavelength and the hemorrhage zone is not differentiated.
• Stage III - the stage of the initial connective tissue organization, occurs in cases of further development of the pathological process (repeated hemorrhages) and is characterized by the presence of local zones of increased density.
• Stage IV - the stage of developed connective tissue organization or mooring, characterized by the formation of moorings and films of high acoustic density.

With CT detachment echographically visualized a membrane of increased acoustic density, corresponding to its dense boundary layer, separated from the retina by an acoustically transparent space.

Clinical symptoms indicating likelihood retinal detachment - one of the main indications for ultrasound. With the A-method of echography, the diagnosis of retinal detachment is based on the stable registration of an isolated echo signal from the detached retina, which is separated by a section of the isoline from the echo signals of the sclera plus retrobulbar tissue complex. This indicator is used to judge the height of retinal detachment. With the B-method of echography, retinal detachment is visualized in the form of a filmy formation in the CT, usually in contact with the membranes of the eye in the projection of the dentate line and optic disc. In contrast to the total with local retinal detachment, the pathological process occupies a certain segment of the eyeball or part of it. Detachment can be flat, 1-2 mm high. Local detachment can be higher, sometimes domed, in connection with which it becomes necessary to differentiate it from a retinal cyst.

One of the important indications for echographic examination is the development of detachment of the choroid and ciliary body, in some cases arising after antiglaucoma operations, cataract extraction, contusion and penetrating wounds of the eyeball, with uveitis. The task of the researcher is to determine the quadrant of its location and flow dynamics. To detect the detachment of the ciliary body, the extreme periphery of the eyeball is scanned in various projections at the maximum angle of inclination of the sensor without a water nozzle. In the presence of a sensor with a water attachment, the anterior sections of the eyeball are examined in transverse and longitudinal sections.

The detached ciliary body is visualized as a membranous structure located 0.5-2.0 mm deeper than the scleral membrane of the eye as a result of the spread of acoustically homogeneous transudate or aqueous humor under it.

Ultrasonic signs of choroid detachment are quite specific: from one to several clearly contoured membranous tubercles of various heights and lengths are visualized, while there are always bridges between the detached areas, where the choroid is still fixed to the sclera: during the kinetic test, the bubbles are motionless. Unlike retinal detachment, the contours of the tubercles usually do not adjoin the optic disc zone.

Detachment of the choroid can occupy all segments of the eyeball from the central zone to the extreme periphery. With a pronounced high detachment, the bubbles of the choroid come closer to each other and give a picture of "kissing" detachment of the choroid.

Prerequisite for rendering foreign body - the difference in the acoustic density of the foreign body material and surrounding tissues. With the A-method, a signal from a foreign body appears on the echogram, by which one can judge its localization in the eye. An important criterion for differential diagnosis is the immediate disappearance of the echo signal from a foreign body with a minimal change in the probing angle. Due to their composition, shape and size, foreign bodies can cause various ultrasonic effects, such as a comet's tail. For visualization of debris in the anterior part of the eyeball, it is better to use a probe with a water cap.

Generally normal Optic disc with ultrasound not differentiated. The ability to assess the condition of the optic nerve disc, both in normal conditions and in pathologies, has expanded with the introduction of color Doppler and energy mapping methods.

In case of congestion due to non-inflammatory edema on B-scans, the optic disc increases in size, prominates into the CT cavity. The acoustic density of the edematous disc is low, only the surface stands out as a hyperechoic band.

Among intraocular neoplasms, creating a "plus-tissue" effect in the eye, melanoma of the choroid and ciliary body (in adults) and retinoblastoma (RB) (in children) are most common. With the A-method of research, the neoplasm is revealed in the form of a complex of echo signals merging with each other, but never decreasing to the isoline, which reflects a certain acoustic resistance of the homogeneous morphological substrate of the neoplasm. The development of areas of necrosis, vessels, lacunae in melanoma is echographically verified by an increase in the difference in the amplitudes of echo signals. With the B-method, the main symptom of melanoma is the presence on the scan of a clear contour corresponding to the tumor boundaries, while the acoustic density of the formation itself can be of varying degrees of homogeneity.

During acoustic scanning, localization, shape, clarity of contours, size of the tumor are determined, its acoustic density is quantitatively assessed (high, low), qualitatively - the nature of the density distribution (homogeneous or heterogeneous).

Thus, the possibilities of using diagnostic ultrasound in ophthalmology are constantly expanding, which ensures the dynamism and continuity of the development of this direction.

Purpose: to study the dynamics of the PZO taking into account the refraction of healthy eyes in healthy children aged 1 month. up to 7 years and compare with PZO of eyes with congenital glaucoma in children of the same age.
Material and methods: studies were carried out on 132 eyes with congenital glaucoma and on 322 healthy eyes. By age, children with congenital glaucoma and healthy eyes were distributed according to the classification of E.S. Avetisova (2003). So, there were 30 newborns with glaucoma (55 eyes), children under 1 year old - 25 (46 eyes), up to 3 years old - 55 (31 eyes). Among the subjects with healthy eyes: newborns - 30 eyes, up to 1 year old - 25 eyes, up to 3 years old - 55 eyes, 4-6 years old - 111 eyes, 7-14 years old - 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 orhthalmology.
Results and Conclusions: Having studied the normal PZO of the eyes at different age periods, we revealed a significant range of fluctuations in PZO indices, the extreme values \u200b\u200bof which may correspond to pathological ones. An increase in the size of the anteroposterior axis of the eye in congenital glaucoma depends not only on the disturbance of the hemohydrodynamic processes of the eye with the accumulation of intraocular fluid, but also on the age-related dynamics of pathological eye growth and the degree of refraction.
Key words: anteroposterior 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 \u200b\u200bmay 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 anteroposterior axis (PZO). Recent studies 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 optic nerve head (optic nerve disc), but also in the fibrous capsule as a whole. This statement is supported by the gradual thinning of the sclera and cornea.
Objective: to study the dynamics of the 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 old - 25 eyes, up to 3 years old - 55 eyes, 4-6 years old - 111 eyes, 7-14 years old - 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 are data on the average values \u200b\u200bof the anatomical and optical elements of healthy eyes, including the anteroposterior axis of the eyes (PZO) at the age from newborn to 25 years (Avetisov E.S., et al., 1987) and from newborns under 14 years of age (Avetisov E.S., 2003, Table 2), in the Republic of Uzbekistan such studies have not been conducted before. Therefore, it was decided to perform echobiometric studies of PZO indicators in 322 healthy eyes in children aged 1 month and older. up to 7 years, taking into account the degree of refraction of the eye and compare the obtained data 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.
The indicators of PZO are normal in almost all age groups, except for newborns, practically coincided with the data given in the table of E.S. Avetisova (2003).
Table 4 shows the data of the PZO of the normal eyes, depending on refraction and age.
The relative dependence of the degree of refraction on the shortening of the PZO of the eye was noted only from 2 years (by 1.8-1.9 mm).
It is known that in the study of IOP in eyes with congenital glaucoma, difficulties arise in determining how 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, easily stretchable. As the intraocular fluid accumulates, they stretch, the eye increases in volume, and the IOP remains within the normal range. At the same time, this process leads to metabolic disorders, damaging the optic nerve fibers and impairing metabolic processes in the ganglion cells. In addition, it is necessary to clearly differentiate between pathological and natural age-related growth of the child's eyes.
Having studied the normal indicators of the PZO of the eyes at different age periods, we found that the extreme values \u200b\u200bof these indicators can correspond to the values \u200b\u200bin pathology. In order to clearly determine whether the eyeball stretching is pathological, we simultaneously analyzed the relationship between PZO parameters and IOP, refraction, the presence of glaucomatous excavation, its size and depth, and the horizontal size of the cornea and its limbus.
So, with the advanced stage of the disease in 10 eyes of newborns with PZO \u003d 21 mm, 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 PZO \u003d 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 old (10 eyes) with PZO \u003d 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 PZO of the eyes exceeded the average norm by 2.9, 2.3 and 2.3 mm, respectively, in each age group.
With the advanced stage of glaucoma in children under 1 year old (45 eyes), the PZO 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 PZO 27.5 mm Pt was 29 ± 1.1 mm Hg. Art. (p≤0.05), disc excavation - 0.6 ± 0.005 (p≤0.05). At the terminal stage (10 eyes) with PZO 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 PZO of the eyes exceeded the average norm by 4.7, 4.8, 6.3 mm, and at 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 disturbance of the hemohydrodynamic processes of the eye with the accumulation of intraocular fluid, but also on the age-related dynamics of the 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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Eye ultrasound (or ophthalmoechography) is a safe, simple, painless and highly informative method for examining eye structures, which allows them to be displayed on a computer monitor as a result of the reflection of high-frequency ultrasonic waves from the eye tissues. If such a study is complemented by the use of color Doppler mapping of the vessels of the eye (or CDC), then the specialist can also assess the state of blood flow in them.

In this article, we will provide information on the essence of the method and its varieties, indications, contraindications, methods of preparing and conducting an ultrasound of the eye. This data will help you understand the principle of this diagnostic method, and you can ask the ophthalmologist any questions that arise.

Ultrasound of the eye can be prescribed both to identify many ophthalmic pathologies (even at the initial stages of their development), and to assess the state of eye structures after surgical operations (for example, after replacing the lens). In addition, this procedure makes it possible to monitor the dynamics of the development of chronic ophthalmic diseases.

The essence and varieties of the method

The principle of ophthalmoechography is based on the ability of the ultrasonic waves emitted by the sensor to be reflected from the tissues of the organ and converted into an image displayed on a computer monitor. Thanks to this, the doctor can receive the following information about the eyeball:

• measure the size of the eyeball as a whole;
• assess the extent of the vitreous body;
• measure the thickness of the inner shells and the lens;
• assess the length and condition of retrobulbar tissues;
• to determine the size or identify tumors of the ciliary region;
• study the parameters of the retina and choroid;
• identify and evaluate characteristics (if it is impossible to determine these changes in time);
• differentiate primary retinal detachment from secondary retinal detachment, which was caused by an increase in tumors of the choroid;
• detect foreign bodies in the eyeball;
• determine the presence of opacities, exudate or blood clots in the vitreous;
• identify.

Such a study can be performed even with opacities of the optical media of the eye, which can complicate the diagnosis using other methods of ophthalmological examination.

Usually, ophthalmoechography is supplemented by Doppler sonography, which allows assessing the condition and patency of the vessels of the eyeball, the speed and direction of blood flow in them. This part of the study makes it possible to detect abnormalities in blood circulation even at the initial stages.

For ultrasound of the eye, the following varieties of this technique can be used:

1. One-dimensional echography (or mode A)... This research method is used to determine the size of the eye or its individual structures and to assess the state of the orbits. When carrying out this technique, a solution is instilled into the patient's eye and the device sensor is installed directly on the eyeball. As a result of the examination, a graph is obtained that displays the parameters of the eye necessary for diagnosis.
2. 2D echography (or B mode)... This method allows one to obtain a two-dimensional picture and characteristics of the structure of the internal structures of the eyeball. For its implementation, no special preparation of the eye is required, and the sensor of the ultrasound device is installed on the closed eyelid of the subject. The study itself takes no more than 15 minutes.
3. Combination of modes A and B... This combination of the above methods makes it possible to obtain a more detailed picture of the state of the eyeball and increases the information content of the diagnosis.
4. Ultrasonic biomicroscopy... This method involves digital processing of the echoes received by the apparatus. As a result, the quality of the image displayed on the monitor increases several times.

Doppler examination of the vessels of the eye is performed according to the following methods:

1. 3D echography... This research method makes it possible to obtain a three-dimensional image of the structures of the eye and its vessels. Some modern devices allow you to get a picture in real time.
2. Power Doppler... Thanks to this technique, a specialist can study the state of blood vessels and evaluate the amplitude and velocity values \u200b\u200bof blood flow in them.
3. Pulsed Wave Doppler... This research method analyzes the noise arising from the blood flow. As a result, the doctor can more accurately assess its speed and direction.

When conducting ultrasound duplex scanning, all the possibilities of both conventional ultrasound and Doppler studies are combined. This method of examination simultaneously provides data not only on the size and structure of the eye, but also on the state of its vessels.

Indications

Ultrasound of the eye can be prescribed in the following cases:

• high degrees or hyperopia;
• glaucoma;
• retinal disinsertion;
• pathology of the eye muscles;
• suspicion of a foreign body;
• diseases of the optic nerve;
• trauma;
• vascular eye pathology;
• congenital anomalies in the structure of the organs of vision;
• chronic diseases that can lead to the appearance of ophthalmic pathologies: accompanied by hypertension, kidney disease;
• monitoring the effectiveness of treatment of oncological eye pathologies;
• monitoring the effectiveness of therapy for vascular changes in the eyeball;
• assessment of the effectiveness of the performed ophthalmic operations.

Doppler ultrasound of the eye is indicated for the following pathologies:

• spasm or obstruction of the retinal artery;
• ocular vein thrombosis;
• narrowing of the carotid artery, leading to impaired blood flow in the ocular arteries.

Contraindications

Ultrasound of the eye is an absolutely safe procedure and has no contraindications.

Patient preparation

Ophthalmoechography does not require special preparation of the patient. When prescribing it, the doctor must explain to the patient the essence and necessity of performing this diagnostic study. Particular attention is paid to the psychological preparation of young children - the child must know that this procedure will not hurt him, and behave correctly during an ultrasound scan.

If it is necessary to use mode A during the study, before the examination, the doctor must clarify the patient's data on the presence of an allergic reaction to local anesthetics and choose a drug that is safe for the patient.

Ultrasound of the eye can be performed both in a polyclinic and in a hospital. The patient should take with him a referral for examination and the results of previously performed ophthalmoechography. Before the procedure, women should not use decorative cosmetics for the eyes, as during the examination, a gel will be applied to the upper eyelid.

How the research is done

Ophthalmoechography is performed in a specially equipped office as follows:

1. The patient sits on a chair in front of the doctor.
2. If mode A is used for examination, a local anesthetic solution is instilled into the patient's eye. After the start of its action, the doctor carefully installs the sensor of the device directly on the surface of the eyeball and moves it as needed.
3. If the study is performed in mode B or Doppler sonography is performed, then anesthetic drops are not used. The patient closes his eyes and a gel is applied to his upper eyelids. The doctor installs the sensor on the patient's eyelid and performs the study for 10-15 minutes. After that, the gel is removed from the eyelids with a napkin.

After the procedure, an ultrasound diagnostic specialist draws up a conclusion and gives it to the patient or sends it to the attending physician.

Indicators of the norm

The interpretation of the results of ophthalmoechography is carried out by an ultrasound diagnostic specialist and the patient's attending physician. For this, the results obtained are compared with the indicators of the norm:

• the vitreous body is transparent and has no inclusions;
• the volume of the vitreous body is about 4 ml;
• anteroposterior axis of the vitreous body - about 16.5 mm;
• the lens is transparent, invisible, its posterior capsule is clearly visible;
• length of the eye axis - 22.4-27.3 mm;
• thickness of inner shells - 0.7-1 mm;
• the width of the hypoechoic structure of the optic nerve - 2-2.5 mm;
• refractive power of the eye with emmetropia - 52.6-64.21 D.

Which doctor to contact

An ultrasound of the eye may be prescribed by an ophthalmologist. For some chronic diseases that cause changes in the state of the eyeball and the fundus, such a procedure may be recommended by doctors of other specialties: a therapist, neuropathologist, nephrologist or cardiologist.

Ultrasound of the eye is a highly informative, non-invasive, safe, painless and easy-to-perform diagnostic procedure that helps to make the correct diagnosis in many ophthalmic pathologies. If necessary, this study can be repeated many times and does not require compliance with any breaks. To conduct an ultrasound of the eye, the patient does not need to carry out special training and there are no contraindications and age restrictions for the appointment of such an examination.

Myopia in the general population is quite common: according to the WHO, 25-30% of the world's population suffers from myopia. Most often, myopia develops in childhood or puberty (from 7 to 15 years) and later either remains at the existing level or progresses. In case of myopia, light rays emanating from objects located in the distance are collected in focus not on the retina, as in a normal eye, but in front of it, as a result of which the image turns out to be indistinct, blurry, blurred.

The state of myopia was first described by Aristotle in the 4th century. BC e. In his writings, the philosopher noted that some people, to better distinguish distant objects, are forced to squint their eyes and called this phenomenon “myops” (from the Greek - “squint”). In modern ophthalmology, myopia has another name - myopia.

Causes of myopia

Normally, at 100% vision, parallel rays from distant objects, passing through the optical media of the eye, are focused on the image point on the retina. In the myopic eye, the image is formed in front of the retina, and only a blurry and blurry picture reaches the light-receiving shell. With myopia, this situation occurs only when the eye perceives parallel light rays, that is, with distant vision. The rays emanating from close objects have a divergent direction and, after refraction in the optical medium, the eyes are projected strictly onto the retina, forming a clear and clear image. Therefore, a patient with myopia sees poorly in the distance and well near.

For a clear distinction of distant objects, it is necessary to give the parallel rays a diverging direction, which is achieved with the help of special (spectacle or contact) diffusing lenses. The refractive power of the lens, indicating how much it is necessary to weaken the refraction of the myopic eye, is usually expressed in diopters (diopters) - it is from this point of view that the magnitude of myopia is determined, which is indicated by a negative value.

Myopia is based on the discrepancy between the refractive power of the optical system of the eye and the length of its axis. Therefore, the mechanism of myopia, firstly, may be associated with the excessive length of the optical axis of the eyeball with normal refractive power of the cornea and lens. With myopia, the length of the eye reaches 30 mm or more (with a normal eye length in an adult - 23-24 mm), and its shape becomes elliptical. When the eye is lengthened by 1 mm. the degree of myopia increases by 3 diopters. Secondly, with myopia, too strong refractive power of the optical system (over 60 diopters) may occur at a normal length of the optical axis of the eye (24 mm). Sometimes with myopia there is a mixed mechanism - a combination of these two defects. In both cases, the image of objects cannot focus normally on the retina, but is formed inside the eye; in this case, only focuses from objects located close to the eye are projected onto the retina.

In most cases, myopia is hereditary. In the presence of myopia in both parents, myopia in children develops in 50% of cases; with normal vision of parents - only 8% of children.

A frequent reason contributing to the development of myopia is non-compliance with the requirements of visual hygiene: excessive visual loads at close range, insufficient illumination of the workplace, long-term work at the computer or watching TV, reading in transport, improper sitting when reading and writing.

Often, the development of true myopia is preceded by false myopia caused by overload of the ciliary (accommodative) muscle and accommodation spasm. Myopia may be accompanied by another ophthalmopathology - astigmatism. strabismus. amblyopia. keratoconus. keratoglobus.

Past infections, hormonal fluctuations, intoxication, birth trauma have an adverse effect on visual function. TBI. impairing microcirculation in the membranes of the eye. The progression of myopia is facilitated by the deficiency of such microelements as Mn, Zn, Cr, Cu and others. Incorrect correction of already identified myopia.

Myopia classification

First of all, they distinguish between congenital (associated with intrauterine developmental disorders of the eyeball) and acquired (developed under the influence of unfavorable factors) myopia.

According to the leading mechanism for the development of myopia, axial (with an increase in the size of the eyeball) and refractive myopia (with excessive force of the refractive apparatus) are distinguished.

A condition accompanied by the progression of myopia by 1 or more diopters per year is regarded as progressive myopia. With a constant, significant increase in the degree of myopia, they speak of malignant myopia or myopic disease, which leads to vision disability. Stationary myopia does not progress and is well corrected with the help of lenses (spectacle or contact).

The so-called transient (temporary) myopia, lasting 1-2 weeks, develops when the lens is swollen and its refractive power increases. This condition occurs during pregnancy, diabetes mellitus. taking corticosteroids, sulfonamides, in the initial stage of cataract development.

According to the data of refractometry and the strength of the necessary correction in diopters, weak, medium and high myopia are distinguished:

The degree of high myopia can reach significant values \u200b\u200b(up to -15 and -30 diopters).

Myopia symptoms

For a long time, myopia is asymptomatic and is often detected by ophthalmologists during prophylactic examinations. Usually myopia develops or progresses during school years, when children have to deal with intense visual stress in the process of studying. Attention should be paid to the fact that children begin to distinguish distant objects worse, poorly see the lines on the board, try to get closer to the object in question, looking into the distance, squint their eyes. In addition to distant vision, with myopia, twilight vision also deteriorates: people with myopia are less able to navigate in the dark.

Constant forced eye strain leads to visual fatigue - muscle asthenopia, accompanied by severe headaches. aches in the eyes, pain in the eye sockets. Against the background of myopia, heterophoria, monocular vision and divergent strabismus may develop.

With progressive myopia, patients are often forced to change glasses and lenses for stronger ones, because after a while they no longer correspond to the degree of myopia and correct vision. Myopia progresses due to the stretching of the eyeball and is common during adolescence. The lengthening of the anterior-posterior axis of the eye with myopia is accompanied by the expansion of the palpebral fissure, which leads to a slight bulging. The sclera, when stretched and thinned, acquires a bluish tint due to translucent vessels. The destruction of the vitreous body can be manifested by "flying flies", the feeling of "skeins of wool", "threads" before the eyes.

When the eyeball is stretched, lengthening of the eye vessels, a violation of the blood supply to the retina, and a decrease in visual acuity are noted. The fragility of the blood vessels can lead to hemorrhages in the retina and vitreous humor. The most formidable complication of myopia can be retinal detachment and accompanying blindness.

Diagnosis of myopia

A diagnosis of myopia requires ophthalmic tests. examination of eye structures, refraction studies. conducting an ultrasound of the eye.

Visometry (visual acuity test) is carried out according to the table using a set of trial spectacle lenses and is subjective. Therefore, this type of study with myopia must be supplemented with objective diagnostics: skiascopy. refractometry. which are carried out after cycloplegia and allow you to determine the true value of refraction of the eye.

Ophthalmoscopy and biomicroscopy of the eye with a Goldmann lens for myopia is necessary to detect changes in the retina (hemorrhage, dystrophy, myopic cone, Fuchs spot), bulging of the sclera (staphyloma), lens opacity, etc.

To measure the anterior-posterior axis of the eye and the size of the lens, assess the homogeneity of the vitreous body, exclude retinal detachment, an ultrasound scan of the eye is indicated.

Differential diagnosis is carried out between true myopia and false, as well as transient myopia.

Myopia treatment

Correction and treatment of myopia can be carried out conservatively (drug therapy, spectacle or contact correction), surgical or laser methods.

Medication courses, carried out 1-2 times a year, prevent the progression of myopia. It is recommended to observe hygiene of vision, limiting physical activity, taking vitamins of groups B and C, using mydriatics to relieve spasm of accommodation (phenylephrine), conducting tissue therapy (aloe, vitreous intramuscularly), taking nootropics (piracetam, hopantenic acid), physiotherapeutic treatment ( laser therapy, magnetotherapy, massage of the cervical-collar zone, reflexology).

In the process of treating myopia, orthoptic techniques are used: training of the ciliary muscle using negative lenses, hardware treatment (accommodation training, laser stimulation, color pulse therapy, etc.).

To correct myopia, contact lenses or glasses with diffusing (negative) lenses are selected. To preserve the reserve of accommodation for myopia, as a rule, incomplete correction is performed. With myopia above -3 diopters, the use of two pairs of glasses or glasses with bifocal lenses is indicated. In case of high myopia, glasses are selected based on their portability. Orthokeratological (night) lenses can be used to correct mild to moderate myopia.

To date, ophthalmology has developed more than twenty methods of refractive and laser surgery for the treatment of myopia. Excimer laser correction of myopia involves correcting vision by changing the shape of the cornea, giving it a normal refractive power. Laser correction of myopia is performed for myopia up to -12-15 diopters and is performed on an outpatient basis. Among the methods of laser surgery for myopia, LASIK is the most widely used. SUPER LASIK. EPILASIK. FemtoLASIK. LASEK. photorefractive keratectomy (PRK). These methods differ in the degree of impact and the method of forming the surface of the cornea, however, in essence they are identical. Complications of laser treatment of myopia can be hypo- or hypercorrection, the development of corneal astigmatism, keratitis. conjunctivitis. dry eye syndrome.

Refractive lens replacement (lensectomy) is used in cases of high myopia (up to –20 diopters) and loss of the natural accommodation of the eye. The method consists in removing the lens and placing an intraocular lens (artificial lens) with the necessary optical power inside the eye.

Phakic lens implantation. as a method of treating myopia, it is used with preserved natural accommodation. In this case, the lens is not removed, but in addition, a special lens is implanted into the anterior or posterior chamber of the eye. By implanting phakic lenses, very high (up to –25 diopters) degrees of myopia are corrected.

Radial keratotomy is rarely used in modern myopia surgery due to the large number of limitations. This method involves the application of blind radial incisions to the periphery of the cornea, which grow together and change the shape and optical power of the cornea.

Scleroplastic surgery for myopia is performed in order to stop the growth of the eye. In the process of scleroplasty, strips of biological grafts are placed behind the fibrous membrane of the eyeball, covering the eye and preventing it from stretching. Another operation, collagenoscleroplasty, is also aimed at curbing the growth of the eye.

In some cases, with myopia, it is advisable to carry out keratoplasty - transplantation of the donor cornea, which is given a certain shape using software modeling.

The optimal method of treating myopia can be determined only by a highly qualified ophthalmologist (laser surgeon), taking into account the individual characteristics of visual impairment.

Forecast and prevention of myopia

With appropriate correction of stationary myopia, in most cases, it is possible to maintain high visual acuity. With progressive or malignant myopia, the prognosis is determined by the presence of complications (amblyopia, staphyloma of the sclera, retinal or vitreous hemorrhage, dystrophy or retinal detachment).

With a high degree of myopia and changes in the fundus, heavy physical labor, lifting weights, work associated with prolonged visual stress are contraindicated.

Prevention of myopia, especially in children and adolescents, requires the development of visual hygiene skills, special gymnastics for the eyes and general strengthening measures.

An important role is played by preventive examinations aimed at detecting myopia in risk groups, medical examination of people with myopia, preventive measures, rational and timely correction.

Myopia - what is it? Myopia Eye Treatment

What provokes the disease

The main symptoms of myopia: looking into the distance, a person begins to squint, and when driving a car or playing sports, the eyes quickly get tired.

Sometimes myopia is accompanied by other ocular pathologies, for example, astigmatism, amblyopia, or keratoglobus.

What is myopia and how does it develop?

Both types of vision problems are manifested because the image of objects when looking into the distance does not focus on the retina, but occurs inside the eye. These two causes of myopia can also be expressed in a complex.

Risk factors due to which eye myopia can be triggered:

Having felt the signs of myopia, a person goes to the doctor to diagnose and prescribe glasses. To correct the distance between the retina and the focus, here you need glasses marked "minus" (with diffusing, concave lenses). Diopters will be determined by an ophthalmologist depending on the safety of vision and the degree of ailment (from low to high).

Different types of myopia

The level of the disease depends on the distance between the focus and the retina.

There are three degrees of myopia:

1. Low degree. The above distance is no more than three diopters. The eyeball does not lengthen by more than one and a half millimeters. When looking into the distance, the contours of objects are only slightly blurred.
2. Medium. The distance in this case exceeds three diopters and gets to six. The length of the eyeball grows by three millimeters. Visual clarity is lost at a distance of more than 30 cm.
3. High degree. The distance grows by six or more diopters. With a high degree of the disease, thinning of the retina and blood vessels occurs, and a person is only able to see something very close to the eyes. The level of high myopia can reach enormous values: diopters can go off scale for three dozen. The higher the degree of myopia, the more the retina and blood vessels are stretched. This can cause progressive vision loss and even blindness.

With severe myopia and degeneration of the fundus, you will have to give up serious physical activity, including sports, as well as work involving eye strain.

How to define myopia? In the absence of clouding in the lens and other parts of the eye with a decrease in distant vision, the doctor diagnoses "myopia". The disease can be congenital and acquired, that is, manifested under the influence of various external factors. Most often, acquired myopia is detected in adolescents, but it can also be found in adults.

Myopia tends to deteriorate with age. Why can an elderly person develop senile myopia? Age-related disease is usually associated with an increase in the refractive abilities of the lens. She is often accompanied by another ailment - hyperopia. With age, an elderly person may develop a combined disease, when both the refractive power and the length of the eyeball exceed the standards.

The rapid development of the disease is possible not only in the elderly, the progression of myopia is not necessarily associated with age. The causes of myopia are in great physical and emotional stress. Progressive myopia is especially common in adolescents.

This diagnosis assumes that one or even two diopters are added every year. With a heavy load on the eyesight of schoolchildren during puberty, the condition is worsened by hormonal changes and emotional instability. In addition, the entire organism grows, including the eyes.

A progressive disease is also possible in athletes, in particular if the activity involves lifting weights and frequent concussions (martial arts). With temporary myopia, the lens swells, its refractive power increases, and a person sees poorly on average for a week. The development of such a condition causes diabetes mellitus, some drugs, for example, of the steroid group, the initial stage of cataracts. pregnancy.

There is also false myopia. caused by a spasm of the accommodating muscles of the eye. Its development occurs with a heavy load on the eyes, as well as with infectious ailments, tuberculosis, problems with blood vessels, rheumatic exacerbations. Pseudomyopia is curable: if the doctor's recommendations are followed, the disease goes away quickly. But if there is no therapy, then the false ailment will turn into a real one.

To accurately determine the type of disease, stop the progression and prescribe the correct treatment, doctors use traditional and modern diagnostics. It includes a variety of studies: urine and blood tests, electrocardiogram, ultrasound and MRI. The first step is ophthalmic tests. Visual acuity is checked using a table and a set of trial glasses. But it is necessary to confirm the diagnosis with a refraction test and skiascopy.

If myopia is high, when degenerative changes in the retina are noticeable, ophthalmoscopy and biomicroscopy of one or both eyes are performed, depending on the degree of damage.

Ways to improve vision with myopia

Can myopia be cured? Modern medicine answers this question positively. Treatment of myopia should be based on the reasons that provoked the disease. It can be both operational and conservative. How to get rid of myopia without surgery?

Myopia

Emmetropia - the focus is on the retina. Myopia - the focus is in front of the retina.

Nearsightedness is a visual defect called myopia in professional medical terminology. The term myopia comes from the Greek myops - squinting eyes.

According to statistics, every third person on Earth suffers from myopia. This pathology of eye refraction is manifested by a decrease in visual acuity in the distance. Near-sighted people have poor vision of distant objects, but they see well objects located at close range.

In the overwhelming majority of cases, myopia is caused by a discrepancy between the refractive power of the optical system of the eye and the length of its axis. In myopia, parallel light rays entering the eye are focused in front of the retina, and not on its surface, as is the case in a healthy eye. Depending on the reasons why this happens, myopia is classified as follows: - axial - when the refractive power of the optical media of the eye (cornea, lens, vitreous body) is within normal values, but its anteroposterior size is greater than in the emmetropic eye - refractive - when, with a normal anteroposterior size of the eye, the refractive power of the optics is greater than in the emmetropic eye - mixed - both the refractive power of the optics of the eye and its anteroposterior size exceed normal values \u200b\u200b- combined - in cases where the refractive power of the optics of the eye and its anteroposterior size does not go beyond the values \u200b\u200binherent in the emmetropic eye, but is combined in unsuccessful variants.

Myopia can be congenital or acquired. Congenital myopia is rare, but, as a rule, it is complicated, that is, it is accompanied by anomalies in the development of the eye and low vision (amblyopia) in the absence of correction during the development of the child's eye or pathology that cannot be treated. Acquired myopia in recent years has become increasingly common, in many cases for a number of reasons (for example, during the growth of the body), it can progress, leading to further deterioration of vision. Myopia is recognized as progressive if a decrease in vision occurs by one or more diopters every year. There are three degrees of myopia: weak - up to 3 diopters, medium - from 3.25 to 6 diopters and high degree - over 6 diopters. The degree of myopia determines the number of diopters by which the refractive power of the eye must be reduced in order for it to become emmetropic.

Usually myopia develops with increased growth of the eyeball, therefore, the progression of myopia is observed mainly among young children, and the average age when the process stabilizes is approximately 18-20 years.

Strenuous visual work at close range contributes to the development of myopia, which explains the very common visual impairment in children in primary school. Some scientific studies confirm the relationship of excessive stress of accommodation with the progression of myopia. Their results underlie the conclusions that the habitually excessive stress of accommodation stimulates the development of false myopia in a child, which turns into true myopia in the absence of timely treatment. In recent years, the continuing increase in the volume of visual work, including with the use of display equipment (computers, e-books, mobile phones, etc.) has led to an increase in the number of patients with accommodation spasm. According to many ophthalmologists, its long-term presence contributes to the growth of the anterior-posterior size of the eyeball and true myopization of the eye.

Physiological myopia does not further lead to a significant loss of visual acuity, but if the process is not stabilized and the eyeball continues to grow, myopic disease occurs. Myopia progresses with the greatest intensity in students - usually at the stage of maximum visual stress, which occurs in parallel with the growth of the body. High myopia and especially myopic disease is a serious disease that leads to pathological changes in the vascular and retina of the eye, predisposing to complications such as retinal detachment, glaucoma, which can lead to complete loss of vision.

Prevention of myopia and its progression is of paramount importance, especially since this pathology leads to a decrease in vision at working age, and this entails extremely negative socio-economic consequences.

Recently, the prevalence of myopia among young people has been growing rapidly in Asian countries (in particular, Hong Kong, Taiwan, Singapore), where 80-90% of schoolchildren are exposed to it. For comparison: in the USA and European countries, this figure is much less, but also high - 20-50%. In recent years, there has been an increase in the incidence of myopia in schoolchildren: more than 50% of graduates of secondary schools and gymnasiums in Russia are currently registering myopic refraction.

An early onset of the disease may indicate an increased risk of developing high myopia. The first signs of myopia are squinting, a low tilt of the head, and the child's desire to sit closer to the TV. Eye pain may occur when working at close range. headache. It is extremely important to timely identify vision problems; from the moment the child starts school, it is advisable to check visual acuity annually and, if it decreases, start treatment on time.

myopia - short-sightedness, lack of foresight; blindness, short-sightedness, myopia. Ant. foresight, foresight Dictionary of Russian synonyms. myopia 1. blindness 2. see short-sightedness ... Glossary of synonyms

Nearsightedness - (Myopia, brachymetropia) is a known refractive error of the ocular apparatus. As you know, refraction is generally called the ability of the eye to connect a certain beam on the retina, due to its anatomical structure. For the norm ... ... Encyclopedia of Brockhaus and Efron

Nearsightedness - nearsightedness, myopia (from the Greek.myo squinting and ops eyes; it has long been noticed that, squinting eyes, nearsighted people see better), refractive error (see), with a swarm, the disparity of the length of the eye with its refractive power is expressed in the predominance of the first over ... ... Big Medical Encyclopedia

Myopia - myopia, myopia, many others. no, wives. 1. Lack of vision, characteristic of myopic. Suffer from myopia. 2. transfer. Shortsightedness, shortsightedness. In his calculations, he discovered extreme myopia. Ushakov's explanatory dictionary. DN ... ... Ushakov's Explanatory Dictionary

Myopia - (myopia), lack of vision, in which close objects are clearly visible and poorly distant; the result of increased refractive power of the optical media of the eye (cornea, lens) or too long an axis (with normal refractive power) ... ... Modern encyclopedia

Myopia - (myopia) lack of vision, in which close objects and poorly distant objects are clearly visible; the result of increased refractive power of the optical media of the eye (cornea, lens) or too long an axis (with normal refractive power) ... ... Big Encyclopedic Dictionary

Myopia - myopia, see also myopia ... Scientific and technical encyclopedic dictionary

myopia - myopia, oh, oh; uk. Ozhegov's Explanatory Dictionary. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 ... Ozhegov's Explanatory Dictionary

nearsightedness - nearsightedness1, nearsightedness - nearsighted, half-sighted, outdated. blind, colloquial. decrease blind-balling myopia2, col. decrease blindness ... Dictionary-thesaurus of synonyms of Russian speech

nearsightedness - myopia A deficiency of the eye, consisting in the fact that the back focus of the eye lies in front of the retina in the absence of accommodation. [Collection of Recommended Terms. Issue 79. Physical optics. USSR Academy of Sciences. Scientific and Technical Terminology Committee. 1970 ... Technical translator's guide

Myopia - This article or section needs revision. Please improve the article according to the rules for writing articles ... Wikipedia

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