Ultrasound diagnostics of the eye: how is the procedure, what equipment is used. How is echobiometry of the eye Ultrasound scan performed?

A highly informative and painless method of ultrasound scanning is widely used in all areas of examination without interfering with the patient's organs. The ophthalmological field for diagnosing pathologies and anomalies of the eye is no exception. Eye examinations are carried out in A-scan and B-scan modes.

In this case, using ultrasound scanning, both the general condition of the eye and specific data, for example, the so-called eye length, are assessed. The ability to carry out certain movements depending on the structure of the eye muscle tissues, nerve endings and the presence or absence of pathologies in the form of opaque optical media or neoplasms of the eyeball.

Ultrasound uses the ability of high frequency sound waves to reflect off various tissues, as well as structures and organs. In this case, the reflected waves with the help of a transducer transmit information to the monitor screen, thereby visualizing the organ under study. At the same time, the state of the choroid of the eye is assessed, the localization and level of blood circulation of the vessels are assessed.

What is A- and B-scan. What is the difference between A and B scanning

Ultrasonic A - eye scanning or eye echobiometry - is a measurement of the dimensions of the depth of the anterior eye chamber, the geometric dimensions (thickness) of the lens, and the measurement of the length of the eye. As for the indicator of the length of the eye, it matters in the pathology of myopia, since the higher the length of the eye, the greater the myopia.

A-scan of the eye refers to one-dimensional scanning. All information is displayed on the monitor screen in the form of a graph with a horizontal and vertical axis, with the help of which the specialist evaluates the current state of the eye structures. Corneal curvature data obtained from keratometry and eye axis length (from A-scan) are used to calculate the refractive power of the intraocular lens.

B-scan of the eye or two-dimensional scan is performed to study the tissues of the eye. Using this method, the condition of the anterior and posterior parts of the lens, its cornea is studied, and the retina and sclera are scanned. Ultrasound of the eye to obtain more accurate data on its condition, the sensor is placed at different angles, performing a B-scan.

How is the echobiometry procedure performed?

Ultrasound of the eye lasts from a quarter to half an hour, sometimes up to 40 minutes, depending on the scanning method. Wherein:

• the subject must be with eyes open in the A-scan mode and closed during the B-scan;
• to improve the sliding of the sensor, a gel is applied to the patient's eyelids;
• when performing a one-dimensional scan, the sensor is placed on the eyes, and in a two-dimensional study, it is necessary that the sensor be placed on the closed eyelids in a certain position. And then smoothly move it;
• the specialist who conducts the ultrasound, from time to time, tells the patient what actions to take with the eyes.

Ultrasound of the eyes can be performed in the direction of an ophthalmologist in a polyclinic, in an ophthalmological hospital, in a diagnostic center, if they are equipped with both ultrasound machines and specialists of the appropriate profile.

What other ultrasound examinations of the eyes are used

Evaluation of the optical density of the scan area is carried out using special computer programs. Ultrasonic biomicroscopy (USB) makes it possible to visualize the anatomical structures of the anterior segment of the eye and obtain a detailed image of the cornea, anterior chamber, lens and retrolens space with a high degree of resolution. It is possible to identify and assess the pathology of the angle of the anterior chamber, the iris and the zone of the ciliary body. Ultrasound allows us to clarify the extent of lysis of the fibers of the zinn ligament and, in case of a narrow rigid pupil, is an additional method for detecting insolvency of the ligamentous apparatus of the lens. To predict the result of the operation, an important task is to assess the functional state of the posterior segment of the eye.

Ultrasound diagnostics significantly improves the examination of patients with opaque optical media of the eye. It is best if this type of study is performed by the surgeon who will operate on the patient, and not by a specialist in the diagnostic department. During the study, the surgeon can fully assess the patient's condition, which allows optimizing the choice of tactics for his treatment. If ultrasound equipment is installed in the surgeon's office, it is used much more often and does not require extra time to prepare for work. Unlike ophthalmoscopy, ultrasound should not be trusted by nursing staff.

Understanding physical principles the interaction of ultrasonic energy and body tissues is necessary for accurate. In ophthalmology, a reflected ultrasonic echo pulse is used. Short ultrasonic pulses have a frequency of 10 MHz or more, the central pulse repetition rate is 1-5 kHz, which allows the sensor to capture the reflected echo signal. Knowing the average speed of propagation of ultrasonic energy in tissues (~1540 m/s) makes it possible to calculate in real time and display on a flat display the distance between the transducer and the echo-reflecting structure in a two-dimensional projection (2D). An ultrasonic wave is reflected and refracted at the boundary between media of different acoustic density.

If the surface piezoelectric crystal sensor has a small radius of curvature, then the depth of field of the spatial image at the focus point will be insufficient. A longer eye (25mm) requires a more uniform focus to obtain an appropriate depth of field. A wide beam of ultrasonic waves (3 mm at a level of 6 dB) is characterized by insufficiently high lateral resolution. Images of targets located at a close distance appear double on the display, and those located far from the sensor appear smeared in the lateral areas. Such errors are inevitable if computed sonography is not used, but it is not currently available for performing ultrasound in ophthalmology.

Axial permission depends on the frequency, at a higher frequency it is higher. Higher frequencies are more easily absorbed by biological structures, so more power is needed to provide sensitivity to a weak echo. The risk of developing cataracts determines the maximum power that can be used safely. In practice, experts have come to a compromise that ultrasound should be used with a frequency of 10-20 MHz and an axial resolution of about 0.15 mm, which is an order of magnitude higher than the lateral resolution. Axial resolution is reduced if a broad beam of waves is reflected from curved surfaces such as those seen in TOC.

Better ultrasonic reflection achieved when a beam of ultrasonic waves is incident perpendicular to the surface. The waves reflected from the wall of the orbit in the region of the equator of the eye give a weak reflected signal. Even with the correct echo amplitude, not all circular cross-sections of the eye can be shown on the display.

Because speed sound higher in denser structures such as the lens, the structures behind it are projected closer on the display than they actually are, and the wave is refracted along the edge of the lens. The lens, IOL, IOIT and scleral fillings, characterized by high acoustic density, give multiple internal reflections, appearing on the display as evenly distributed false echoes with reduced amplitude behind the main echo signal of these structures. Echoes are produced by paradoxical movements as the probe is moved, which aids in their recognition. Dense structures such as calcified retrolental membranes, IOLs, and IOITs create significant shadows behind them due to absorption of acoustic energy.

Absorption of ultrasonic energy, when it passes twice through tissues, results in the display of distant structures with a relatively smaller echo amplitude. Electronic amplification of the echo from distant targets can compensate for this absorption. This technique is called gain time scaling.

Usage electronic devices, which automatically display the surface of structures such as the cornea, lens capsule, retina and sclera, leads to diagnostic errors. Increasing the amplitude and clipping of the peaks to show the surface of the structures on the display means that all echoes are displayed with identical amplitudes. With this approach, the ST and the retina in the image can be easily confused. In addition, electronic differentiation in determining the surface of structures eliminates the lowest amplitude echoes within the lens, CT, subretinal fluid (SRF), suprachoroidal space, and tumors.

A-scan. Amplitude ultrasonography (A-scan) is an original ultrasound method, but has no significant practical value in the presence of opaque optical media of the eye. As a result of A-scan, a flat one-dimensional image (ID) is obtained, and finding the necessary information on it is as difficult as “a needle in a haystack”. A very experienced diagnostician can spatially integrate a one-dimensional image and derive some benefit from the resulting data. The less experienced diagnostician, however, has much more trouble interpreting his results. The informativeness of quantitative A-scan for diagnosis is much less than is commonly believed. The amplitude of the echo signal during A-scanning largely depends on the angle at which ultrasonic waves are reflected from the studied structures of the eye. An oblique angle causes significant attenuation of the reflected signal.

Folds detached retina will create areas of strong and weak echo. For this reason, the A-scan is characterized by a large error in the results.

B-scan. A sectoral ultrasound, or B-scan, is a two-dimensional (2D) study that scans sections, or tissue planes, as opposed to an ID spot A-scan. The echo image appears on the display as intensity-modulated pixels. As with A-scanning, structures located strictly perpendicular to the direction of ultrasonic waves reflect a stronger signal. For this reason, the cornea, anterior and posterior lens capsules, sclera or retina are best displayed. The equatorial part of the sclera and the nucleus of the lens are less visible, unless the position of the eyeball is changed or the sensor is placed at different angles. It is possible to assess whether such actions are necessary during the study.

3D visualization of the eyes. Slow rotation of the scanning sector allows to obtain volumetric conical images that can be displayed on the display as 3D conical images or 3D slices, using perspective, shadows, parallax (the apparent change in the position of an object when the observer moves), and various other digital graphics technologies. Since the images are formed when a beam of ultrasonic waves originates from a single point, structures with surfaces located not perpendicular to the scanning beam will be indistinguishable or they will have a smaller echo amplitude. Modern 3D ultrasound machines are of minimal value in the diagnosis of vitreoretinal pathology, they are best used to determine the volume of the tumor.

Ultrasound is often used to detect eye diseases. It is a safe, effective and informative method practiced by ophthalmologists. With its help, the slightest changes in the eyeball are studied, the structure of the muscles is assessed, and pathological formations are determined.

Ultrasound diagnosis of the eye: description of the method

Decreased visual acuity negatively affects the quality of life. Therefore, it is necessary to contact an ophthalmologist in time. Then the chances of recovery increase. After the examination, the specialist prescribes an examination to clarify or make a diagnosis.

One of the most common ways to determine diseases is ultrasound diagnostics of the eye. This is a manipulation based on the penetration and subsequent reflection of high-frequency waves from tissues. The information is received by the computer. At the final stage, the image appears on the monitor.

Ultrasound of the eye is performed using modern equipment. This technique does not require much time, large financial costs and special training. During the diagnostics, the specialist studies the structural features of the retina, muscles, and lens. The procedure is prescribed for the final diagnosis, before and before surgery. Also, the technique is used to monitor the dynamics of the course of the disease.

Ultrasound examination of the eye is a popular way to detect pathological processes and changes in internal tissues.

The procedure is indicated in the presence of numerous problems:

• retinal detachment
• neoplasms
• cataract
• myopia, farsightedness
• glaucoma
• the presence of a foreign body in the eye
• vascular diseases
• abnormal development of the eyeball
• hemorrhage
• traumatic eye injury

Ultrasound is widely used in ophthalmology. The non-invasive method is applied to patients of different ages. It is the ideal solution for screening and looking for changes. A miniature sensor determines pathological processes of an extraordinary configuration and localization. Therefore, in patients who timely applied to a medical institution, diseases are detected at an early stage. This is an important advantage that ensures successful treatment.

Ultrasound does not affect the usual life of a person. Some patients experience mild discomfort. Such an unpleasant symptom disappears soon. If a person works at a computer or drives a vehicle, rest is needed after the diagnosis. You can not engage in the above activities, since excessive eye strain is unacceptable.

High-quality ultrasound diagnostics of the eye is carried out in clinics and public hospitals equipped with innovative scanners. Qualified specialists use different techniques:

• One-dimensional echography is an effective way to determine the size of the eye, internal structures and elements. It is used before surgery. An anesthetic is instilled into the eye for pain relief. The essence of the procedure is that the specialist drives the sensor along the eyelid. The information obtained is displayed on a computer monitor in the form of a graph, which indicates the key parameters of the eyeball
• two-dimensional echography - a scan used to evaluate the internal structure of the organ of vision. A two-dimensional picture appears on the computer screen in the form of numerous dots of varying degrees of brightness. This technique is widely used. The procedure is carried out for 15 minutes. The patient does not feel discomfort
• combined method - it combines the advantages of one- and two-dimensional echography. It is in demand in private clinics, outpatient centers. After the procedure, the ophthalmologist makes an accurate diagnosis and develops a treatment regimen
• Three-dimensional echography is an advanced technique, which means obtaining a three-dimensional image of the organ of vision. This is an effective way that opens up wide possibilities. The ophthalmologist examines the structure of the eye orbits and draws the right conclusions. Private clinics use advanced equipment with high functionality. Therefore, it is possible to receive a picture in real time
• color duplex scanning is an effective method during which vascular diseases are detected. The study is aimed at studying the blood flow. It is carried out quickly and efficiently. The specialist evaluates the results obtained, comparing them with normal indicators. The procedure is absolutely safe. Ultrasonic waves do not have a negative effect on the body

Contraindications, preparation for the study

Ultrasound diagnostics of the eye is based on the principle of echolocation. This is a method for determining diseases of the organ of vision, which has many advantages: harmlessness, simplicity and convenience, affordability of the service. An important advantage is painlessness, since there is no need for injections and incisions.

Ultrasound diagnosis of the eye can be performed in patients who do not have the following contraindications:

• penetrating eyelid wounds
• damage to the eye, in which the integrity of the structures is impaired
• bleeding

There are no other contraindications. Therefore, ultrasound diagnostics of the eye is widely used in private clinics and public medical institutions. It is used to detect tumors, congenital features of the organ of vision, and inflammatory processes. Studies recommend adults, children, pregnant women.

Ultrasound diagnostics of the eye is carried out according to the doctor's prescription in the presence of diseases. It is also possible to conduct research for preventive purposes. Thus, the development of many eye diseases is prevented.

Special preparation for the diagnostic procedure is not required. A special rule applies to the fair sex. Make-up must be removed before the examination because the sensor is placed on the upper eyelid.

How is an eye ultrasound done?

Depending on the data that needs to be clarified by the ophthalmologist, there are two types of research:

• The patient lies on the couch and closes his eyes. A hypoallergenic gel is applied to the eyelids, designed for ultrasound diagnostics. A sensor is placed on the upper eyelid. The results of the study are recorded in the protocol. The procedure takes about half an hour. In some cases, the doctor asks the patient to make chaotic eye movements. The information received is deciphered by a qualified doctor specializing in this area.
• The patient is seated in a comfortable chair. Superficial anesthesia is carried out. This is done with two goals: to achieve immobility of the eye and to ensure painless manipulation. The eyes remain open. A sterile probe is placed on the surface of the eyeball

For ultrasound, medical institutions are equipped with modern equipment. This refers to the A / B scanner and pachymeter. These are new generation devices that are safe to use. They provide fast calculation of IOL according to rational formulas. With the help of advanced devices, intraocular tumors, partial or complete retinal detachment, and traumatic injuries of the organ of vision are detected. The equipment is installed in medical institutions, whose leaders prefer practical solutions. It pays off quickly. Why? Clients actively turn to ophthalmological clinics that provide high-quality service.

A / V scanner AVISO is in great demand. This is a device designed by leading engineers. The ultrasound equipment was produced by the French company Quantel Medical. This is a well-known manufacturer, with the help of which early and accurate diagnostics are carried out.

A/V scanner AVISO is a new model based on PC. This device is equipped with a variety of sensors. It is intended for visualization of the anatomical and topographic structures of the orbit, the lens, the fundus of the eye and for conducting detailed studies of anomalies. The high accuracy of the procedure is ensured by a biometric sensor with a laser target. With the help of such a device, a person’s gaze is fixed, and the axes of the eyes and ultrasonic rays are combined.

The scanner from the French company has important advantages:

• excellent resolution
• increased functionality
• recording a video scan sequence
• clear interface
• the equipment is equipped with a color touch screen
• portability
• application of various formulas for calculating the IOL
• a huge amount of memory designed to store information about patients

In medical institutions that keep up with the times, the Compact Touch pachymeter is installed. This is a piece of equipment that combines several functions. With its help, B-scan, pachymetry and biometrics are performed. The device is compact and ergonomic. Its main advantages include ease of use, high-quality images, and an intuitive interface.

Other technical features are also important:

• displaying multiple images on a monitor
• high measurement accuracy
• the device is equipped with a touch screen
• storage of a large database of patients is provided
• reliability
• mobility due to the presence of a transport case
• fixation of a person's gaze when using a biometric sensor
• long equipment life
• availability of additional accessories: keyboard, mouse with two types of connectors, as well as a printer compatible with the Windows operating system

Pachymeter Compact Touch is an innovative 3-in-1 ultrasound equipment from the French company Quantel Medical. The global manufacturer took into account significant aspects and created an effective device. The device is a ready-made workplace for a doctor specializing in ultrasound of the eye. You don't need a computer to display the results. Information is promptly displayed on the touch screen.

Ultrasound of the eye: norm and interpretation

After the diagnostic procedure, the specialist examines the data obtained. To check the results, a table of normal indicators is used:

1. vitreous body volume is 4 ml
2. thickness of the inner shells - this parameter varies between 0.7-1 mm
3. lens transparent
4. the length of the eye axis is a significant parameter. Norm - 22.4-27.3 mm
5. the vitreous body is transparent
6. refractive power - 52.6-64.21 diopters

Deciphering the results is an important step. If abnormalities are detected, the ophthalmologist prescribes treatment. He is guided by the information received and his own knowledge.

Ultrasound diagnostics of the eye is an effective way, thanks to which pathology is detected at the initial stage and internal tissues are carefully examined. With timely identification of the problem, it is possible to prevent the development of complications and save vision. Therefore, people who care about their health come to the ophthalmological clinic and use the services of qualified specialists!

The medical terms "A-scan of the eye" and "echobiometry" are used to refer to a diagnostic method aimed at measuring the depth of the anterior eye chamber, the length of the eyeball and the thickness of the lens. These measurements are not only of diagnostic value in determining myopia and other disorders, but, along with data on the parameters of the corneal curvature, allow you to determine the strength of the IOL before surgery.

You can undergo the procedure in the ophthalmological clinic "Sphere". We conduct comprehensive research using modern equipment, which allows us to obtain accurate information, thanks to which the results of any treatment will be better.

What is it - echobiometry of the eye?

A-scan of the eye is a one-dimensional ultrasound scan, during which all data are displayed on the monitor in the form of a corresponding graph. Diagnosis can be carried out using ultrasound equipment or optically.

Indications and contraindications for A-scan

How is an A-scan done?

A-scan (ultrasound of the eye) involves the use of anesthetic drops. Immediately before the procedure, the doctor instills them into the patient's eye in order to eliminate discomfort, blinking and tearing. The patient assumes a sitting or lying position. The doctor places the sensor on the surface of the open eye and gently moves it. The data obtained during the scanning process enters the computer and is displayed on the monitor.

Interpretation of A-scan results

By comparing the results obtained with normal parameters, the ophthalmologist can determine the patient's myopia or hypermetropia. For example, the normal length of the eye axis is 23 mm. If the patient has myopia, they exceed them, hyperopia, on the contrary, decrease. Based on the data obtained, the patient can choose glasses or contact lenses, determine the tactics of treatment or plan an operation.

Benefits of A-scan in our clinic

The Sphere Clinic has been providing its services to everyone who wants to see well for more than 20 years and is a recognized leader in its field. We have a powerful diagnostic base, which includes an echobiometry unit. This is an ultrasonic scanner "A-Scan Plas", created at the production facilities of the company "Accutome" (USA). It can be used to scan any type of eye, including those with mature cataracts. IOL calculations performed by A-Scan Plas allow achieving maximum accuracy: up to 0.25D.

In order to get an appointment with our specialists, use the online form on our website or call us: +7 495 139-09-81.

Ultrasound of the eye- a method for diagnosing ophthalmic diseases, visualizing the structure of the eye, the state of the optic nerves, muscles and blood vessels, the lens, the retina. It is used as part of a comprehensive diagnosis of myopia, hyperopia, astigmatism, retinal dystrophy, cataracts, glaucoma, eye tumors, injuries, vascular pathologies, neuritis. Several variants of the procedure are common: one-dimensional (A), two-dimensional (B), three-dimensional (AB) scanning, ultrasound/USDS of vessels. The cost depends on the selected ultrasound mode.

Preparation

Ultrasound of the eye does not require advance preparation. Immediately before the procedure, it is necessary to remove makeup from the eyes, remove contact lenses. If a foreign body is suspected in the eye tissues, an x-ray of the eye is performed before an ultrasound examination. With the development of a neoplasm of any etiology, preliminary diaphanoscopy or X-ray examination is recommended.

What shows

The result of an A-mode ultrasound of the eye is a one-dimensional image, the resulting parameters are used to calculate the strength of the intraocular lens before cataract surgery. In the B-mode, a two-dimensional image of the orbits and eyeballs is obtained, the study reveals corneal opacities, cataracts, hemorrhages, foreign bodies, neoplasms in the eye. In complex AB mode, eye structures are displayed in 3D. The study of blood vessels reflects the features of blood flow in real time through graphical and quantitative indicators. Ultrasound of the eye can detect the following pathologies:

• Myopia, hypermetropia. The length of the anteroposterior axis of the eyeball is measured. With congenital myopia, it is more than normal, with farsightedness - less.
• Cataract. Normally, this structure is transparent and does not appear on the monitor. When clouded, the lens thickens and begins to reflect ultrasound waves - it becomes visible.
• Degenerative-dystrophic diseases. Retinal degeneration, optic nerve atrophy, glaucoma, keratopathy, conjunctival dystrophy are accompanied by thinning and cell death. On ultrasound images, the affected areas become less bright - from white and light gray to gray, barely visible.
• Neoplasms, foreign body. The study allows you to determine the size and location of the tumor, a foreign object in the eye. On ultrasound, they look like areas of increased and high echo activity.
• Pathology of the optic nerves. An assessment of the state of the optic nerve fibers is necessary for retrobulbar neuritis, neurogenic tumors, glaucoma, and traumatic lesions. The change in the thickness of the shell and disk of the nerve, the expansion of certain sections of it, the fading of the boundaries is determined.
• Vascular pathologies of the eye. Ultrasound of the eye vessels is used to analyze blood flow in age-related, diabetic, atherosclerotic changes. The study reveals thrombosis of small and large vessels, non-perfused microvessels, vascular malformations, narrowing of the lumen, poor branching, slowing of blood flow, wriggling and undulating course of vessels.

In addition to the above, ultrasound of the eye is prescribed to detect congenital anomalies in the development of the organ of vision, diseases of the lacrimal glands and lacrimal sac. Despite the high information content, the results of ultrasound cannot be the only confirmation of the diagnosis. They are used in combination with data from a clinical survey, anamnesis, ophthalmological examination, radiography and other instrumental methods.

Advantages

Currently, eye ultrasound is the most informative and accessible method for the early diagnosis of ophthalmic pathologies. The advantages of the method include harmlessness: the absence of radiation exposure and invasive intervention allows examination of children, the elderly, pregnant women, nursing mothers. The short duration of the examination procedure and the relatively low cost make ultrasound one of the most common methods for screening eye diseases. The disadvantage of ultrasound examination of the eye is that the clarity of the image is limited by the area of ​​the sensor, the resolution is lower than with MRI and CT.