Optical coherence tomography. Optical coherence tomography: a technology that has become a reality What is retinal tomography

For a complete diagnosis of most ophthalmological diseases, it is not enough simple methods. Optical coherence tomography allows you to visualize the structure of the organs of vision and identify the smallest pathologies.

Benefits of OCT

Optical coherence tomography (OCT) is an innovative method of ophthalmological diagnostics, which consists of visualizing the structures of the eye in high resolution. It is possible to assess the condition of the fundus and elements of the anterior chamber of the eye at the microscopic level. Optical tomography allows you to study tissues without removing them, therefore it is considered a gentle analogue of a biopsy.

OCT can be compared with ultrasound and computed tomography. The resolution of coherence tomography is much higher than that of other high-precision diagnostic instruments. OCT allows you to detect the smallest damage down to 4 microns.

Optical tomography is the diagnostic method of choice in many cases because it is non-invasive and does not use contrast agents. The method does not require radiation exposure, and the images are more informative and clear.

Specifics of diagnostics using OCT method

Different body tissues reflect light waves differently. During tomography, the delay time and intensity of reflected light as it passes through tissue are measured. eyeball. The method is contactless, safe and highly informative.

Because the light wave moves very high speed, direct measurement indicators is not possible. To decipher the results, a Michelson interferometer is used: the beam is divided into two beams, one of which is directed to the area being examined, and the second to a special mirror. A low-coherence beam of infrared light with a wavelength of 830 nm is used to examine the retina, and a wavelength of 1310 nm is used to examine the anterior segment of the eye.

Read also: – cancer arising from the immature retina.

When reflected, both beams enter the photodetector and an interference pattern is formed. The computer analyzes this picture and converts the information into a pseudo-image. In the pseudo-image, areas with high degree reflections appear warmer, and areas where the reflection is lower may appear almost black. Normally, nerve fibers and pigment epithelium appear “warm”. The average degree of reflection in the plexiform and nuclear layers of the retina, and vitreous appears black because it is optically transparent.

OCT capabilities:

assessment of morphological changes in the retina and nerve fiber layers;
determination of the thickness of eye structures;
disk parameters measurement optic nerve;
assessment of the state of the structures of the anterior chamber of the eye;
determination of the spatial relationship of the elements of the eyeball in the anterior segment.

To obtain a three-dimensional image, the eyeballs are scanned longitudinally and transversely. Optical tomography may be difficult due to corneal edema, opacities, and hemorrhage in the optical media.

What can be examined in the process of optical tomography

Optical tomography makes it possible to study all parts of the eye, but the condition of the retina, cornea, optic nerve, and elements of the anterior chamber can be most accurately assessed. A separate tomography of the retina is often performed to identify structural abnormalities. More accurate methods for studying the macular zone do not currently exist.

For what symptoms is OCT prescribed:

sudden decrease in visual acuity;
blindness;
blurred vision;
spots before the eyes;
increased intraocular pressure;
acute pain;
exophthalmos (bulging of the eyeball).

In the process of optical coherence tomography, it is possible to evaluate the angle of the anterior chamber and the degree of functioning of the drainage system of the eye in glaucoma. Similar studies are carried out before and after laser correction vision, keratoplasty, installation of intrastromal rings and phakic intraocular lenses.

Optical tomography is performed if the following diseases are suspected:

(congenital and acquired);
tumors of the organs of vision;
increased intraocular pressure;
proliferative vitreoretinopathy;
atrophy, swelling and other abnormalities of the optic nerve head;
epiretinal membrane;
thrombosis of the central retinal vein and other vascular diseases;
retinal disinsertion;
macular holes;
cystoid macular edema;
deep keratitis;
corneal ulcers;
progressive myopia.

Coherence tomography is absolutely safe. OCT allows you to identify minor defects in the structure of the retina and begin treatment on time.

For the purpose of prevention, OCT is performed for:

diabetes mellitus;
surgical intervention;
hypertension;
severe vascular pathologies.

Contraindications to optical coherence tomography

The presence of a pacemaker and other devices is not a contraindication. The procedure is not carried out in conditions where a person cannot fix his gaze, as well as in mental disorders and confusion.

The contact environment in the organ of vision can also become an interference. By contact medium is meant the one that is used in other ophthalmic examinations. As a rule, several diagnostic procedures not carried out in one day.

High-quality images can only be obtained in the presence of transparent optical media and a normal tear film. It can be difficult to perform OCT in patients with a high degree of myopia and optical opacities.

How is optical coherence tomography performed?

Optical coherence tomography is carried out in special medical institutions. Even in big cities it is not always possible to find an ophthalmology office with an OCT scanner. A retinal scan of one eye will cost approximately 800 rubles.

No special preparation for tomography is required; the study can be performed at any time. This procedure requires an OCT scanner, an optical scanner that sends beams of infrared light into the eye. The patient is seated and asked to fix his gaze on the mark. If it is not possible to do this with the examined eye, the gaze is fixed with the second one, which sees better. For a full scan, two minutes in a stationary position is enough.

During the process, several scans are made, and after that the operator selects the highest quality and most informative images. The result of the study is protocols, maps and tables, from which the doctor can determine the presence of changes in the visual system. The tomograph's memory contains a regulatory database that contains information about how many healthy people there are similar indicators. The smaller the match, the greater the likelihood of pathology in a particular patient.

Morphological changes in the fundus, visible on OCT images:

high degree of myopia;
benign formations;
scleral staphyloma;
diffuse and focal edema;
swelling with subretinal neovascular membrane;
retinal folds;
vitreoretinal traction;
lamellar and macular hole;
through macular hole;
macular pseudohole;
detachment pigment epithelium;
serous detachment of the neuroepithelium;
Druze;
ruptures of the pigment epithelium;
diabetic macular edema;
macular cystoid edema;
myopic retinoschisis.

As can be seen, the diagnostic capabilities of OCT are extremely diverse. The results are displayed on the monitor as a layered image. The device independently converts signals that can be used to assess the functionality of the retina. It is possible to make a diagnosis based on OCT results within half an hour.

Interpretation of OCT images

To correctly interpret the results of optical coherence tomography, the ophthalmologist must have in-depth knowledge of retinal and choroidal histology. Even experienced specialists cannot always compare tomographic and histological structures, so it is advisable to have OCT images reviewed by several doctors.

Fluid accumulation

Optical tomography makes it possible to identify and evaluate the accumulation of fluid in the eyeball, as well as determine its nature. Intraretinal fluid collection may indicate retinal edema. It can be diffuse and cystic. Intraretinal fluid collections are called cysts, microcysts, and pseudocysts.

Subretinal accumulation indicates serous detachment of the neuroepithelium. The images show elevation of the neuroepithelium, and the angle of detachment from the pigment epithelium is less than 30°. Serous detachment, in turn, indicates CSC or choroidal neovascularization. In rare cases, detachment is a sign of choroiditis, choroidal formations, angioid bands.

The presence of subpigment fluid accumulation indicates detachment of the pigment epithelium. The photographs show elevation of the epithelium above Bruch's membrane.

Neoplasms in the eye

Optical tomography can show the epiretinal membranes (folds in the retina) and evaluate their density and thickness. With myopia and choroidal neovascularization, the membranes appear as fusiform thickenings. They are often combined with fluid accumulation.

Hidden neovascular membranes appear on imaging as irregular thickening of the pigment epithelium. Neovascular membranes are diagnosed in age-related macular degeneration, chronic CSC, complicated myopia, uveitis, iridocyclitis, choroiditis, osteoma, nevus, pseudovitelliform degeneration.

The OCT method allows you to determine the presence of intraretinal formations (cotton wool-like foci, hemorrhages, hard exudate). The presence of cotton wool-like foci on the retina is associated with ischemic nerve damage in diabetic or hypertensive retinopathy, toxicosis, anemia, leukemia, and Hodgkin's disease.

Hard exudates may be star-shaped or isolated. They are usually localized at the border of retinal edema. Such formations are found in diabetic, radiation and hypertensive retinopathy, as well as in Coats disease and wet macular degeneration.

Deep formations are observed with macular degeneration. Fibrous scars appear, which deform the retina and destroy the neuroepithelium. On OCT, such scars give a shadow effect.

Pathological structures with high reflectivity on OCT:

nevus;
hypertrophy of the pigment epithelium;
scarring;
hemorrhages;
hard exudate;
cotton wool tricks;
neovascular membranes;
inflammatory infiltrates;

Pathological structures with low reflectivity:

cysts;
edema;
detachment of the neuroepithelium and pigment epithelium;
shading;
hypopigmentation.

Shadow effect

High optical density tissues can obscure other structures. Based on the shadow effect in OCT images, it is possible to determine the location and structure of pathological formations in the eye.

The shadow effect is given by:

dense preretinal hemorrhages;
cotton wool tricks;
hemorrhages;
hard exudates;
melanoma;
hyperplasia, hypertrophy of the pigment epithelium;
pigment formations;
neovascular membranes;
scarring.

Retinal characteristics on OCT

Puffiness is the most common cause thickening of the retina. One of the advantages of optical tomography is the ability to evaluate and control the dynamics different types retinal edema. A decrease in thickness is observed with age-related macular degeneration with the formation of atrophy zones.

OCT allows you to evaluate the thickness of a certain layer of the retina. The thickness of individual layers can change with glaucoma and a number of other ophthalmological pathologies. The retinal volume parameter is very important in identifying edema and serous detachment, as well as in determining the dynamics of treatment.

Optical tomography can reveal:

Age-related macular degeneration. One of the main causes of visual impairment in people over 60 years of age. Although in the diagnosis of dystrophy they use different methods, optical coherence tomography remains the leading one. OCT allows you to determine the thickness choroid for macular degeneration, it can be used to differential diagnosis with central serous chorioretinopathy.
Central serous chorioretinopathy. The disease is characterized by detachment of the neurosensory layer from the pigment epithelium. In most cases, chorioretinopathy disappears spontaneously within 3-6 months, although in some cases fluid accumulates, causing permanent visual impairment. Chronic CSC requires special treatment. As a rule, these are intravitreal injections and laser coagulation.
Diabetic retinopathy. The pathogenesis of the disease is due to vascular damage. Diagnostics allows you to identify retinal edema and check the condition of the vitreous body (including identifying posterior detachment).
Macular hole, epiretinal fibrosis. Using OCT, you can determine the degree of retinal damage and plan tactics surgical treatment and evaluate the results.
Glaucoma. For elevated intraocular pressure, tomography is additional method examinations. The method is very useful in normotensive glaucoma, when damage to the optic nerve is noted with normal indicators intraocular pressure. OCT can confirm the disease and determine its stage.

Optical coherence tomography is the safest and most informative method examinations of the visual system. OCT is allowed to be performed even in patients who have contraindications to other high-precision diagnostic methods.

OCT is used in various fields of medicine - for diseases gastrointestinal tract, organs respiratory system, in gynecology and for the diagnosis of arthritis and arthrosis. But optical coherence tomography was first used in ophthalmology.

Eyes - very important organ, whose main function is vision

The human eye is a paired organ that performs the function of vision. Consists of the optic nerve, eyeball, and auxiliary organs, in particular muscles, eyelids.

Through the organs of vision, a person receives 80% (according to some sources more than 90%) of information from the outside. Loss of vision, even partial, negatively affects the life of a person and his relatives.

It is important to take care of your eyes - the visual organs are susceptible to many diseases. Some arise in the eye itself, called primary, these include:

retinal detachment;
color blindness;
conjunctivitis.

Optical coherence tomography - what is it and who is its author?

Ocular CT is performed using special equipment

People have many problems with their visual organs, and successfully combating them directly depends on the correctness of the chosen course of treatment. And this requires accurate and timely diagnosis.

Used in medicine different kinds research - , (visual acuity study), . One of the most reliable, accurate and painless methods is optical coherence tomography, what is it?

The idea of using light waves for diagnostics belongs to the American scientist Carmen Puliafito. The doctor gave his theory scientific basis— since the structure of living tissue has a non-uniform density, acoustic waves are reflected from them at different speeds.

The word coherent means “flowing in a consistent manner over time.” The device measures the time it takes for a beam of light to linger as it reflects off different layers of tissue. These readings are analyzed and information about the condition of the organs being examined is obtained.

The operation of the method is the same as with, where ultrasonic waves with a resolution measured in microns are used to study biological material. Optical coherence tomography uses infrared radiation.

The video will show how OCT of the eye is performed:

Advantages of the method

Oct eyes - modern look diagnostics

A laser device is used, which allows you to obtain clear, high-resolution images. The device takes pictures of those layers of the retina (without damaging healthy tissue) that were inaccessible to previous diagnostic methods.

In what cases is it advisable to conduct this type of research:

in patients with almost all diseases - this is especially important if the patient has poor dilation or does not dilate (this can happen with diabetes mellitus), glaucoma;
at any age - in young children and elderly people;
the procedure does not take much time, it lasts only 5-7 minutes;
no contrast agents are required, as the method is non-invasive.
has a repeat scanning function, this is important for patients with gaze fixation problems.
V in electronic format it is possible to transfer information to any medical institution at the request of the patient.

The equipment operates according to latest technology using a blue laser and allows diagnosing: the structure of the retina in layers, pathological changes, glaucoma and multiple sclerosis in the early stages, its progression, age-related macular degeneration eyes.

Research process

To obtain a high-quality image, during the examination the patient must focus his gaze on a special mark. The operator scans the image, makes several copies, choosing the better one.

If for some reason this eye cannot be tested, the second eye is examined. Based on the test results in the form of tables, cards determine the condition of the tissues.

Indications and contraindications for the use of optical coherence tomography:

While safe, it has several contraindications:

In order to scan an image, the patient needs to fix his gaze at a certain point for 2.5 seconds. Some people can't do this various reasons, in this case it is not possible to conduct research.
Heavy mental illness person, in which it is impossible to contact doctors and the device operator.

Optical coherence tomography may be of poor quality if the environment of the eye has lost its transparency. But this cannot be a reason to refuse such a study, which is carried out in specialized clinics.

Diagnostic cost

Oct eyes: result

The optical coherence tomography procedure, which can be done without a doctor’s referral, is still paid for for all patients. Prices for examinations depend on the area of the eye in which the examination (scan) is required.

Types of method:

Study of the disc in glaucoma, neuritis. Diagnostic results help to establish or clarify the disease, as well as determine how effective the treatment is and whether it is chosen correctly.
With OCT of the retina, the central part of the eye is examined, the macula is examined in cases of hemorrhage, swelling and ruptures, retinopathy (the appearance of a veil or spots before the eyes), and in various inflammatory processes.
Scanning allows you to obtain information about all its layers (done before and after surgery on the cornea).

Prices for examinations vary; before enrolling in a particular medical institution, they must be clarified. The average cost of optical coherence tomography is as follows:

optic disc (one eye) - 1000 rubles;
retinal periphery with pupil dilation (2 eyes) - 2500 rubles;
OCT + angiography (1 eye) — 2000 rub.

The procedure is possible in eye clinics and ophthalmology centers in many cities. These can be either private or government agencies. Some offer patients a discount on services. For example, if diagnostics are carried out at night, the price can be reduced by 35-40%.

The eyes give us information about the world around us, making life colorful and interesting. But no one is immune from diseases and injuries; if this happens, there is no need to waste time, you should immediately contact a doctor, since an advanced disease is more difficult to cure.

Method optical coherence tomography(optical coherence tomography, abbreviated as OST (eng.) or OCT (rus.)) is a modern, high-precision non-invasive study of various structures of the eye. OCT is a non-contact method that allows a specialist to visualize eye tissue with very high resolution (1 - 15 microns), the accuracy of which is comparable to microscopic examination.

The theoretical foundations of the OCT method were developed in 1995 by the American ophthalmologist K. Pulafito, and already in 1996 - 1997 the Carl Zeiss Meditec company introduced it into clinical practice The first device for optical coherence tomography. Today, OCT devices are used for diagnostics. various diseases fundus and anterior segment of the eye

Indications for OST

The optical coherence tomography method allows:

visualize morphological changes in the retina and nerve fiber layer, as well as assess their thickness;
assess the condition of the optic nerve head;
examine the structures of the anterior segment of the eye and their relative spatial arrangement.

The method can be used in ophthalmology to diagnose many pathologies of the posterior part of the eye, such as:

degenerative changes in the retina (congenital and acquired, AMD)
cystoid macular edema and macular hole
epiretinal membrane
changes in the optic nerve head (abnormalities, swelling, atrophy)
diabetic retinopathy
thrombosis of the central retinal vein
proliferative vitreoretinopathy.

Regarding pathologies of the anterior part of the eye, OST can be used:

to assess the angle of the anterior chamber of the eye and the functioning of drainage systems in patients with glaucoma
in case of deep keratitis and ulcers of the cornea
during examination of the cornea during preparation and after laser vision correction and keratoplasty
for control in patients with phakic IOLs or intrastromal rings.

Video of our specialist

How the research works

The patient is asked to fix the gaze of the eye being examined on a special mark, after which the doctor performs a series of scans and selects the most informative image to assess the condition of the organ of vision. Diagnosis is completely painless and takes minimal time.

We found 66 clinics where you can undergo optical coherence tomography / OCT in Moscow.

How much does optical coherence tomography / OCT cost in Moscow

Prices for optical coherence tomography / OCT in Moscow from 900 rubles. up to 21270 rub..

Optical coherence tomography / OCT: reviews

Patients left 2,535 reviews of clinics that offer optical coherence tomography/OCT.

What is the essence of OCT?

Optical coherence tomography (OCT) is a non-invasive diagnostic method that allows tomographic ( cross sections) and three-dimensional visualization and internal microstructure organ by comparing scattered and reflected light with an accuracy of 2 to 15 microns in real time. Such high accuracy makes it possible to obtain data on the structure of tissues comparable to histological studies, which allows us to call this study an “optical biopsy”.

The technique is used to assess the condition of the retina through transparent media, diagnose skin tumors, and perform catheter and endoscopic examinations of blood vessels (including coronary arteries), atherosclerotic plaques, endometrium, cervical epithelium and Bladder, gastrointestinal tract.

When conducting surgical operations OCT can help differentiate tumor tissues through visual assessment.

What does it show? What diseases does it diagnose?

As an ophthalmic diagnostic tool, OCT is useful in diagnosing many retinal diseases:

Macular hole (hole)
Macular wrinkle
Vitreomacular traction
Macular edema
Papilledema
Glaucoma
Detachments of the retina and retinal pigment epithelium (eg, central serous retinopathy or age-related macular degeneration).

In some cases, only with this diagnostic study diagnosis can be made (eg, macular hole). For other diseases, especially vascular diseases retina, it may be useful to combine the study with an angiogram. The study also allows you to assess the condition of the cornea and anterior chambers of the eye.

As an optical biopsy system, the method allows the diagnosis of precancerous conditions and malignant neoplasms, lesions of vascular walls, gynecological diseases.

During endoarterial assessment of vessels, a spiral scan is performed, which allows one to obtain three-dimensional images of the structures of the vascular wall and differentiate different types of atherosclerotic plaques.

Optical tomography is also used in the diagnosis of skin tumors.

How is the research going?

The equipment uses an absolutely safe laser light source, without x-rays. The scan is completely painless and takes only a few seconds.

Contraindications and restrictions

A retinal examination is not possible if the transparency of the eye media is limited due to vitreous hemorrhage, cataracts or corneal opacities.

Endoscopic or catheter tomography is limited by contraindications for these types of diagnostic interventions.

One of the main tasks of any branch of medicine is to make 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 were used to study eye diseases. Now one of the most modern and safe technologies is. The first optical coherence tomograph was created in 2001.

Operating principle of optical coherence tomography

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

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

Advantages of using optical coherence tomography

The use of OCT has a number of clear advantages. The study is completely non-invasive, i.e. The tissues of the eye are not injured at all. With the OCT method, the ophthalmologist obtains two- and three-dimensional images of the fundus of the eye. It is important to note that all scanograms 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 a 10 times 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 its core. early stage its development.

Optical coherence tomography is well suited for diagnosing retinal detachment, retinal dystrophy, etc. Many doctors recognized the high diagnostic value this method for diseases of the retina. IN ophthalmological center Professor Konovalov uses only the most modern equipment and techniques that will not only restore your vision, but also prevent the occurrence of such problems.