Today, such a study is the most advanced technology for studying the structures of the organ of vision. This is an irreplaceable way early diagnosis diseases retina and other pathologies leading to blindness. Previously, such dangerous and serious illnesses developed in patients largely because they did not undergo a high-quality ophthalmological examination on time. Consider how an eye tomography is performed, what kind of method it is, why it is becoming so popular.

Diagnostic indications

Ophthalmologists use this type of examination to detect the following ailments.

• Macular tears.
• Eye damage as a result of diabetes mellitus.
• Glaucoma.
• Thrombus blockage central vein retina.
• Detachment of this part of the organ of vision, which is one of the most dangerous conditions that contribute to the development of blindness.
• Degenerative changes in the cavities of the eye.
• Age-related macular degeneration.
• The appearance of cystic formations on the retina.
• Swelling and other abnormalities of the nerve, leading to a significant decrease in visual acuity and even blindness.
• Vitreoretinopathy.

In addition, eye tomography is also used to monitor the effectiveness of previously prescribed treatments. With its help, you can most fully determine the angle of the anterior chamber of the eye, the features of its work drainage system(This is why tomography gives the most accurate results for suspected glaucoma). It is also irreplaceable when installing an intraocular lens and performing keratoplasty.

This examination allows you to diagnose the condition of the cornea, optic nerve, iris, retina and anterior chamber of the eye. It should also be noted that all results are stored in the memory of the device, which allows the doctor to track the dynamics of the eye condition.

How is the examination carried out?

This is a type of modern non-invasive procedure for diagnosing eye tissue. It is very similar to an ordinary ultrasound examination, with one difference - it does not use sound, but infrared rays. All information comes to the monitor after measuring the degree of radiation delay from the tissue to be examined. Such tomography makes it possible to detect changes that cannot be determined by other methods.

This study is most effective in relation to the retina of the eye and the optic nerve. Despite the fact that this type of diagnosis has been used in medical practice for a little more than 20 years, it has managed to gain popularity.

During the examination, the patient should focus on the highlighted mark. This must be done with the help of the eye that must be studied. At the same time, scanning of the tissues of the organ of vision is carried out. If the person is unable to focus their gaze on the mark, they should use the other eye that sees better.

If there are hemorrhages, edema, opacity of the lens, then the information content of the procedure is sharply reduced. Other methods can be used to determine an accurate diagnosis.

The tomography results are presented in the form of summarized tables, pictures and detailed protocols. The doctor can analyze the condition of the eye using quantitative and visual data. They are compared with the indicators of the norm, which makes it possible to make an accurate diagnosis.
Recently, three-dimensional examination has also been used. Thanks to layer-by-layer scanning of the membranes of the eye, the doctor identifies almost everything possible violations in him.

The advantages of this diagnostic method

Retinal tomography has the following advantages:

• it allows you to accurately determine the presence of glaucoma in a person;
• makes it possible to record the progression of the disease;
• does not cause painful sensations and discomfort;
• most accurately diagnoses macular degeneration, that is, a condition in which a person sees black spot in sight;
• Combines perfectly with other methods of detecting eye diseases leading to blindness;
• does not expose the body to harmful radiation (primarily X-ray).

What such research can define

Tomography, used to study the features of the structure of the eye, allows you to see various diseases, processes and phenomena in this body.

• Any morphological changes in the retina or nerve fibers.
• Any changes in the parameters of the nerve disc.
• Features of the anatomical structures in the anterior segment of the eye, and their changes in comparison with the norm.
• Any cases of degenerative changes in the retina, leading to significant impairment of vision.
• Disorders associated with the development of diabetic retinopathy, including initial stages difficult to diagnose with conventional ophthalmoscopy.
• Defeats vitreous and other areas of the eye associated with the development of glaucoma.
• Changes in the retina resulting from vein thrombosis.
• Different degrees of retinal detachment.
• Various anomalies of the structure of the eye, optic nerve and other disorders requiring detailed diagnosis.

Such an examination is carried out in specialized clinics with the appropriate equipment. Of course, few diagnostic centers have such equipment. However, over time, it becomes more accessible, and more and more clinics will accept patients for examining their eyes using a progressive method. Recently, OCT (optical coherence tomography) has become available in the clinics of regional centers.

And although the cost of CT is quite high, you should not refuse to perform it, especially if the ophthalmologist insists on just such a diagnosis. It has much more capabilities than a simple medical examination, even with the use of high-precision equipment. So it will be possible to detect dangerous eye pathologies even at the stage when the symptoms are not yet expressed.

There are a limited number of ways to visualize the exact structure and the smallest pathological processes in the structure of the organ of vision. The use of simple ophthalmoscopy is absolutely insufficient for a complete diagnosis. Relatively recently, since the end of the last century, optical coherence tomography (OCT) has been used to accurately study the state of eye structures.

OCT of the eye is a non-invasive, safe method of examining all structures of the organ of vision in order to obtain accurate data on the smallest damage. In terms of resolution, no high-precision diagnostic equipment can be compared with coherence tomography. The procedure allows you to detect damage to the eye structures with a size of 4 microns.

The essence of the method is the ability of an infrared light beam to reflect unequally from various structural features of the eye. The technique is close at the same time to two diagnostic manipulations: ultrasound and computed tomography. But in comparison with them, it wins significantly, since the images are clear, the resolution is large, there is no radiation exposure.

What can you explore

Optical coherence tomography of the eye allows you to evaluate all parts of the organ of vision. However, the most informative manipulation is when analyzing the features of the following eye structures:

• cornea;
• retina;
• optic nerve;
• front and rear cameras.

A particular type of research is optical coherence tomography of the retina. The procedure allows you to identify structural abnormalities in this eye area with minimal damage. For the examination of the macular zone - the area of ​​greatest visual acuity, OCT of the retina has no full-fledged analogues.

Indications for manipulation

Most diseases of the organ of vision, as well as symptoms of eye damage, are indications for coherence tomography.

The conditions in which the procedure is carried out are as follows:

• retinal tears;
• dystrophic changes in the macula of the eye;
• glaucoma;
• optic nerve atrophy;
• tumors of the organ of vision, for example, choroidal nevus;
• acute vascular diseases of the retina - thrombosis, ruptured aneurysms;
• congenital or acquired anomalies of the internal structures of the eye;
• myopia.

In addition to the diseases themselves, there are symptoms that are suspicious of retinal damage. They also serve as indications for research:

• a sharp decrease in vision;
• fog or "flies" in front of the eye;
• increased eye pressure;
• sharp pain in the eye;
• sudden blindness;
• exophthalmos.

except clinical indications, there are also social ones. Since the procedure is completely safe, it is recommended to be carried out by the following categories of citizens:

• women over 50;
• men over 60;
• all those suffering from diabetes mellitus;
• in the presence of hypertension;
• after any ophthalmic interventions;
• in the presence of severe vascular accidents in history.

How is the study going

The procedure is carried out in a special room equipped with an OCT tomograph. This is a device with an optical scanner, from the lens of which infrared light beams are directed to the organ of vision. The result of the scan is recorded on the connected monitor in the form of a layer-by-layer tomographic image. The device converts the signals into special tables, according to which the structure of the retina is assessed.

Preparation for the examination is not required. Can be done at any time. The patient, being in a seated position, focuses his gaze at a special point indicated by the doctor. It then remains still and focused for 2 minutes. This is enough for a full scan. The device processes the results, the doctor assesses the state of the eye structures and within half an hour a conclusion is issued on the pathological processes in the organ of vision.

Eye tomography using an OCT scanner is performed only in specialized ophthalmological clinics. Even in large metropolitan areas, there is not a lot of medical centers offering a service. The cost varies depending on the scope of the study. Fully OCT of the eye is estimated at about 2 thousand rubles, only the retina - 800 rubles. If you need to diagnose both organs of vision, the cost doubles.

Since the examination is safe, there are few contraindications. They can be represented as follows:

• any condition when the patient is unable to fix his gaze;
• mental illness, accompanied by a lack of productive contact with the patient;
• lack of consciousness;
• the presence of a contact medium in the organ of vision.

The last contraindication is relative, since after washing out the diagnostic medium, which may be after various ophthalmological examinations, for example, gonioscopy, the manipulation is performed. But in practice, the two procedures are not combined in one day.

Relative contraindications are also associated with the opacity of the eye media. Diagnostics can be performed, but the images are not as good quality. Since there is no radiation, there is also no effect of the magnet, the presence of pacemakers and other implanted devices is not a reason for refusing the examination.

Diseases for which the procedure is prescribed

The list of diseases that can be detected by OCT of the eye looks like this:

• glaucoma;
• retinal vascular thrombosis;
• diabetic retinopathy;
• benign or malignant tumors;
• retinal rupture;
• hypertensive retinopathy;
• helminthic invasion of the organ of vision.

Thus, optical coherence tomography of the eye is absolutely safe method diagnostics. It can be used in a wide range of patients, including those for whom other high-precision research methods are contraindicated. The procedure has some contraindications, it is performed only in ophthalmological clinics.

Taking into account the harmlessness of the examination, it is advisable to perform OCT for all people over 50 to detect small structural defects of the retina. this will make it possible to diagnose diseases on early stages and maintain high-quality vision longer.

The possibilities of modern ophthalmology have been significantly expanded in comparison with the methods of diagnosing and treating diseases of the organs of vision some fifty years ago. Today, complex, high-tech devices and techniques are used to make an accurate diagnosis, to detect the slightest changes in the structures of the eye. Optical coherence tomography (OCT) performed with a special scanner is one such method. What is it, to whom and when to conduct such a survey, how to properly prepare for it, are there any contraindications and are complications possible - the answers to all these questions are below.

Benefits and Features

Optical coherence tomography of the retina and other elements of the eye is an innovative ophthalmological study, in which superficial and deep structures of the organs of vision are visualized in high quality resolution. This method is relatively new, uninformed patients treat it with prejudice. And it is completely in vain, since today OCT is considered the best that exists in diagnostic ophthalmology.

OCT takes only a few seconds, and the results will be prepared within an hour after the examination - you can come to the clinic at lunchtime, perform OCT, get a diagnosis immediately and start treatment on the same day

The main advantages of OCT include:

• the ability to examine both eyes at the same time;
• the speed of the procedure and the efficiency of obtaining accurate results for the diagnosis;
• in one session, the doctor gets a clear idea of ​​the state of the macula, optic nerve, retina, cornea, arteries and capillaries of the eye at the microscopic level;
• tissues of the elements of the eye can be thoroughly examined without a biopsy;
• the resolution of OCT is many times higher than the indicators of conventional computed tomography or ultrasound - tissue damage not exceeding 4 microns in size, pathological changes at the earliest stages are detected;
• no need to inject intravenously contrasting dyes;
• the procedure is non-invasive, therefore it has almost no contraindications, does not require special preparation and recovery period.

When conducting coherent tomography, the patient does not receive any radiation exposure, which is also a great advantage, taking into account the harmful effects of external factors, and without this, every modern person is exposed.

What is the essence of the procedure

If light waves are passed through the human body, they will be reflected from different organs in different ways. The delay time of light waves and the time of their passage through the elements of the eye, the intensity of reflection is measured using special devices during tomography. Then they are transferred to the screen, after which the decryption and analysis of the data obtained are carried out.

Retinal oc is an absolutely safe and painless method, since the devices do not come into contact with the organs of vision, nothing is injected subcutaneously or inside the eye structures. But at the same time, it provides much higher information content than standard CT or MRI.

This is how the image on a computer monitor, obtained by scanning with OCT, looks like; to decipher it, special knowledge and skills of a specialist will be required

It is in the method of decoding the resulting reflection that lies main feature OCT. The fact is that the waves of light move at a very high speed, which does not allow directly measuring the required indicators. For these purposes, a special device is used - a Meikelson interferometer. It splits the light wave into two beams, then one beam is passed through the eye structures that need to be examined. And the other goes to the mirror surface.

If an examination of the retina and macular zone of the eye is required, a low-coherence infrared beam of 830 nm is used. If you need to do OCT of the anterior chamber of the eye, you will need a wavelength of 1310 nm.

Both beams are connected and enter the photodetector. There they are transformed into an interference image, which is then analyzed by a computer program and displayed on a monitor in the form of a pseudo-image. What will it show? Areas with a high degree of reflection will be colored in warmer hues, while those that reflect light waves weakly will appear almost black in the picture. Nerve fibers and pigment epithelium are displayed "warm" in the picture. Nuclear and plexiform retinal layers have medium reflectivity. And the vitreous body looks black, since it is almost transparent and transmits light waves well, almost not reflecting them.

To obtain a full-fledged, informative picture, it is necessary to pass light waves through eyeball in two directions: transverse and longitudinal. Distortions of the resulting image can occur if the cornea is edematous, opacities of the vitreous body, hemorrhages, and foreign particles occur.

One procedure lasting less than a minute is enough to get the maximum full information about the state of the eye structures, identify developing pathologies, their forms and stages

What can be done with optical tomography:

• Determine the thickness of the eye structures.
• Set the size of the optic nerve head.
• To identify and evaluate changes in the structure of the retina and nerve fibers.
• Assess the condition of the elements of the anterior region of the eyeball.

Thus, during OCT, the ophthalmologist gets the opportunity to study all the components of the eye in one session. But the most informative and accurate is the study of the retina. Today, optical coherence tomography is the most optimal and informative way to assess the state of the macular zone of the organs of vision.

Indications for

Optical tomography in principle, it can be prescribed to every patient who consults an ophthalmologist with any complaints. But in some cases this procedure is indispensable, it replaces CT and MRI and is even ahead of them in terms of information content. The indications for OCT are the following symptoms and patient complaints:

• "Flies", cobwebs, lightning and flashes before the eyes.
• Blurred vision.
• An unexpected and dramatic decrease in vision in one or both eyes.
• Severe pain in the organs of vision.
• Significant increase intraocular pressure with glaucoma or for other reasons.
• Exophthalmos - bulging of the eyeball from the orbit spontaneously or after injury.

Glaucoma, increased intraocular pressure, changes in the optic nerve head, suspicions of retinal detachment, as well as preparation for surgical interventions on the eyes - all these are indications for optical coherence tomography

If vision correction using a laser is to be performed, such a study is carried out before and after surgery in order to accurately determine the angle of the anterior chamber of the eye and assess the degree of drainage intraocular fluid(if glaucoma is diagnosed). OCT is also necessary for keratoplasty, implantation of intrastromal rings or intraocular lenses.

What can be identified and detected with coherence tomography:

• changes in intraocular pressure;
• congenital or acquired degenerative changes in retinal tissue;
• malignant and benign neoplasms in the structures of the eye;
• symptoms and severity of diabetic retinopathy;
• various pathologies of the optic nerve head;
• polyiferative vitreoretinopathy;
• epiretinal membrane;
• blood clots coronary arteries or central vein of the eye and other vascular changes;
• tears or detachment of the macula;
• macular edema, accompanied by the formation of cysts;
• corneal ulcers;
• deeply penetrating keratitis;
• progressive myopia.

Thanks to such a diagnostic study, it is possible to identify even minor changes and abnormalities of the organs of vision, correctly diagnose, determine the degree of lesions and the optimal method of treatment. OCT actually helps to maintain or restore the patient's visual function. And since the procedure is completely safe and painless, it is often performed in preventive purposes with diseases that can be complicated by pathologies from the side of the eyes - with diabetes mellitus, hypertension, disorders of cerebral circulation, after trauma or surgery.

When OCT is not allowed

The presence of a pacemaker and other implants, conditions in which the patient is unable to focus his gaze, is unconscious, or is unable to control his emotions and movements, most diagnostic tests are not carried out. In the case of coherent tomography, everything is different. A procedure of this kind can be carried out with confusion of consciousness and an unstable psychoemotional state of the patient.

Unlike MRI and CT, which, although informative, have a number of contraindications, OCT can be used to examine children without any fear - the child will not be afraid of the procedure and will not receive any complications

The main and, in fact, the only obstacle to performing OCT is the simultaneous conduct of other diagnostic studies. On the day for which OCT is prescribed, it is impossible to use any other diagnostic methods of examining the organs of vision. If the patient has already undergone other procedures, then OCT is transferred to another day.

Also, myopia can become an obstacle to obtaining a clear, informative image. high degree or severe opacity of the cornea and other elements of the eyeball. In this case, the light waves will be poorly reflected and give a distorted image.

OCT technique

It must be said right away that optical coherence tomography is usually not performed in district polyclinics, since ophthalmological offices do not have the necessary equipment. OCT can only be done in specialized private medical institutions... In large cities, it will not be difficult to find a trustworthy ophthalmology office with an OCT scanner. It is advisable to agree on the procedure in advance, the cost of coherence tomography for one eye starts from 800 rubles.

No preparation for OCT is required, only a functioning OCT scanner and the patient himself are needed. The examinee will be asked to sit on a chair and focus on the indicated mark. If the eye, the structure of which is to be examined, is unable to focus, then the gaze is fixed as much as possible by the other, healthy eye. It takes no more than two minutes to be in a stationary state - this is enough to pass beams of infrared radiation through the eyeball.

During this period, several images are taken in different planes, after which the medical officer selects the clearest and highest quality images. Their computer system checks against an existing database compiled from examinations of other patients. The base is represented by various tables and diagrams. The less matches are found, the higher the likelihood that the structures of the patient's eye are pathologically altered. Since all analytical actions and transformations of the obtained data are performed by computer programs in an automatic mode, it will take no more than half an hour to obtain the results.

The OCT scanner produces perfectly accurate measurements, processes them quickly and efficiently. But in order to make a correct diagnosis, it is still necessary to correctly decipher the results obtained. And this requires high professionalism and deep knowledge in the field of histology of the retina and choroid of an ophthalmologist. For this reason, the interpretation of the research results and the diagnosis are carried out by several specialists.

Abstract: The majority of ophthalmic diseases are extremely difficult to recognize and diagnose at early stages, all the more so to establish the real degree of damage to the eye structures. For suspicious symptoms, ophthalmoscopy is routinely prescribed, but this method is not enough to get the most accurate picture of the condition of the eyes. More complete information is given by computed tomography and magnetic resonance imaging, but these diagnostic measures have a number of contraindications. Optical coherence tomography is completely safe and harmless, it can be performed even in cases where other methods of examining the organs of vision are contraindicated. Today it is the only non-invasive way to get the most complete information about the condition of the eyes. The only difficulty that may arise is that not all ophthalmological offices have the equipment necessary for the procedure.

One of the main tasks of any direction of medicine is the formulation of a correct, accurate and, most importantly, timely diagnosis. In order to effectively cope with this task, specialists are constantly improving their technologies. If we talk about ophthalmology, it is worth noting that the eye has a very complex structure and the finest tissues. Until the 90s of the last century, X-rays or ultrasound procedure... Now one of the most modern and safest technologies is. The first optical coherence tomograph was created in 2001.

How optical coherence tomography works

By its principle of operation, tomography is similar to ultrasound, but instead of sound waves, OCT uses optical radiation of the near infrared wavelength range. In other words, the OCT method uses a low-intensity laser beam.

At the Konovalov center, an optical coherence tomograph (OCT) is now used using RTVue processing technology, in which the diagnostic beam reflected from the retina is processed using Fourier Domain OCT analysis. The RTVue system allows high-speed images of retinal tissue non-invasive way and high resolution scans.

The advantage of using optical coherence tomography

The use of OCT has a number of clear advantages. The study is completely non-invasive, i.e. eye tissues are not injured at all. With OCT, the ophthalmologist obtains two- and three-dimensional images of the fundus. It is important to note that all the scans obtained not only reflect the structure of the fundus tissues, but also show functional state fabrics. The resolution of optical coherence tomography is about 10-15 microns (this is 10 times a clearer picture than when using other methods of studying the retina), which makes it possible to see individual cellular layers of the retina in the images and determine the disease at the earliest stage of its development.

Optical coherence tomography is well suited for diagnosing retinal detachment, retinal degeneration, etc. Many physicians have recognized the high diagnostic value this method with diseases of the retina. V ophthalmological center Professor Konovalov, for diagnosis and treatment, only the most modern equipment and techniques are used, which will not only restore your vision, but also prevent the occurrence of such problems.

Optical coherence tomography is a non-invasive (non-contact) method of tissue examination. It allows you to obtain images of higher resolution compared to the results of ultrasound procedures. In fact, optical coherence tomography of the eye is a type of biopsy, only for the first one there is no need to take a tissue sample.

A brief excursion into history

The concept on the basis of which modern optical coherence tomography is performed was developed by researchers in the distant 1980s. In turn, the idea of ​​introducing a new principle into ophthalmology was proposed in 1995 by the American scientist Carmen Puliafito. A few years later, Carl Zeiss Meditec developed a device called the Stratus OCT.

Currently, using the latest model, it is possible not only to study retinal tissues, but also optical coherence tomography of the coronary arteries and the optic nerve at the microscopic level.

Research principles

Optical coherence tomography consists in the formation of graphic images based on the measurement of the delay period when a light beam is reflected from the tissues under study. The main element of devices in this category is a superluminescent diode, the use of which makes it possible to form light beams of low coherence. In other words, when the apparatus is activated, the beam of charged electrons is split into several parts. One stream is directed to the area of ​​the investigated tissue structure, the other - to a special mirror.

The rays reflected from the objects are summed up. Subsequently, the data are recorded with a special photodetector. The information formed on the graph allows the diagnostician to draw conclusions about the reflectivity at individual points of the object under study. When evaluating the next tissue site, the support is moved to a different position.

Optical coherence tomography of the retina makes it possible to form graphs on a computer monitor, which are in many ways similar to the results of an ultrasound examination.

Indications for the procedure

Today, optical coherence tomography is recommended for diagnosing pathologies such as:

• Glaucoma.
• Macular tissue tears.
• Thrombosis of the bloodstream of the retina.
• Degenerative processes in the structure of the eye tissue.
• Cystic edema.
• Abnormalities in the functioning of the optic nerve.

In addition, optical coherence tomography is prescribed to assess the effectiveness of the therapeutic procedures used. In particular, the research method is indispensable in determining the quality of the installation of the drainage device, which is integrated into the eye tissue in glaucoma.

Features of the diagnosis

Optical coherence tomography involves focusing the subject's eyes on special marks. In this case, the operator of the device performs a number of sequential tissue scans.

Significantly hinder research and discourage effective diagnosis capable of such pathological processes as edema, profuse hemorrhages, all kinds of opacities.

The results of coherence tomography are formed in the form of protocols that inform the researcher about the state of certain tissue areas, both visually and quantitatively. Since the obtained data are recorded in the memory of the device, later they can be used to compare the state of tissues before the start of treatment and after the application of therapy methods.

3D rendering

Modern optical coherence tomography makes it possible to obtain not only two-dimensional graphs, but also to produce three-dimensional visualization of the objects under study. Scanning tissue sites at high speed allows you to form more than 50,000 images of the diagnosed material within a few seconds. Based on the information received, a special software reproduces the three-dimensional structure of the object on the monitor.

The generated 3D image serves as the basis for studying the internal topography of the eye tissue. Thus, an opportunity opens up for determining the clear boundaries of pathological neoplasms, as well as fixing the dynamics of their change over time.

Benefits of coherence tomography

Coherence tomography devices are most effective in the diagnosis of glaucoma. In the case of using devices of this category, specialists are able to determine with high accuracy the factors of the development of pathology in the early stages, to identify the degree of progression of the disease.

The research method is indispensable in diagnosing such a common disease as macular degeneration of the tissue, in which, as a result age characteristics the patient's body begins to see a black spot in the central part of the eye.

Coherence tomography is effective in combination with other diagnostic procedures such as fluorescence retinal angiography. When combining the procedures, the researcher receives especially valuable data that contribute to the formulation of the correct diagnosis, the determination of the complexity of the pathology and the choice of an effective treatment.

Where can optical coherence tomography be performed?

The procedure is possible only with a specialized OCT apparatus. Diagnostics of this kind can be used in modern research centers. Most often, such equipment is available in vision correction rooms, private ophthalmological clinics.

The price of the issue

Coherence tomography does not require a referral from the attending physician, but even if available, diagnostics will always be paid. The cost of the study determines the nature of the pathology, which the diagnosis is aimed at identifying. For example, the determination of macular tissue tears is estimated at 600-700 rubles. While the tomography of the tissue of the anterior part of the eye can cost the patient of the diagnostic center 800 rubles or more.

With regard to complex studies aimed at assessing the functioning of the optic nerve, the state of the retinal fibers, the formation of a three-dimensional model visual organ, the price for such services today starts at 1800 rubles.