Optical coherence tomography is a non-invasive (non-contact) method for studying the structure of ocular tissue. It allows you to get higher resolution images in comparison with the results of ultrasound procedures. In fact, optical coherence tomography of the eye is a type of biopsy, only for the first there is no need for 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 at the Massachusetts University of Technology in the distant 1980s. In turn, the idea of introducing a new principle in ophthalmology was proposed in 1995 by the American scientist Carmen Puliafito. A few years later, Carl Zeiss Meditec developed an appropriate 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, optic nerve at the microscopic level.
Research principles
Optical coherence tomography is the formation of graphic images based on the measurement of the delay period when the light beam is reflected from the studied tissues. The main element of devices of this category is a superluminescent diode, the use of which makes it possible to form light rays of low coherence. In other words, when the apparatus is activated, the beam of charged electrons is divided into several parts. One stream is directed to the region of the studied tissue structure, the other to a special mirror.
Rays reflected from objects are added up. Subsequently, the data is recorded by a special photodetector. The information generated on the graph allows the diagnostician to draw conclusions about the reflectivity at individual points of the investigated object. When evaluating the next tissue site, the support is moved to another position.
Optical coherence tomography of the retina makes it possible to form graphs on a computer monitor that are largely similar to the results of ultrasound examinations.
Indications for the procedure
Today, optical coherence tomography is recommended for the diagnosis of pathologies such as:
- Glaucoma.
- Macular tissue breaks.
- Retinal Circulatory Thrombosis.
- Diabetic retinopathy.
- Degenerative processes in the structure of the eye tissue.
- Cystic edema.
- Anomalies in the functioning of the optic nerve.
In addition, optical coherence tomography of the optic nerve is prescribed to evaluate the effectiveness of the used therapeutic procedures. In particular, the research method is indispensable in determining the quality of the installation of a drainage device that integrates into the tissues of the eye with glaucoma.
Features of the diagnosis
Optical coherence tomography involves focusing the subject's vision on special marks. At the same time, the operator of the device performs a series of sequential scans of tissues.
Pathological processes such as swelling of the cornea of the eye, profuse hemorrhage, and all kinds of opacities can significantly impede the study and prevent effective diagnosis.
The results of coherent tomography are formed in the form of protocols that inform the researcher about the state of certain tissue sites both visually and quantitatively. Since the data obtained are recorded in the memory of the device, subsequently they can be used to compare the state of tissues before treatment and after the application of treatment methods.
3D rendering
Modern optical coherence tomography makes it possible to obtain not only two-dimensional graphs, but also produce three-dimensional visualization of the studied objects. Scanning tissue sections at high speed allows you to create more than 50,000 images of the diagnosed material within a few seconds. Based on the information received, special software reproduces the volumetric structure of the object on the monitor.
The generated 3D image is the basis for studying the internal topography of the eye tissue. Thus, the opportunity for determining the clear boundaries of pathological neoplasms, as well as fixing the dynamics of their changes in time, opens up.
Benefits of Coherent Tomography
The most effective devices for coherent tomography demonstrate in the diagnosis of glaucoma. In the case of the use of 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 the diagnosis of such a common disease as tissue macular degeneration, in which, as a result of age-related characteristics of the body, the patient begins to see a black spot in the central part of the eye.
Coherent tomography is effective in combination with other diagnostic procedures, for example, with retinal angiography using a fluorescence method. When combining the procedures, the researcher obtains especially valuable data that contribute to making the correct diagnosis, determining the complexity of the pathology and choosing an effective treatment.
Where can I perform optical coherence tomography?
The procedure is only possible with a specialized OCT apparatus. Diagnosis of such a plan can be resorted to in modern research centers. Most often, such equipment is equipped with vision correction rooms, private ophthalmological clinics.
Issue price
Conducting coherent tomography does not require the direction of the attending physician, but even with it, diagnosis will always be paid. The cost of the study determines the nature of the pathology, the identification of which the diagnosis is aimed at. For example, the definition of macular tissue breaks 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.
As for comprehensive studies aimed at assessing the functioning of the optic nerve, the state of the retinal fibers, the formation of a three-dimensional model of the visual organ, the price of such services starts today from 1800 rubles.