RU2421121C1 - Method of diagnosing dystrophic changes of retina on eye fundus periphery - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to ophthalmology. Estimation of dystrophic changes on eye fundus is carried out by colour images of eye fundus. After obtaining digital image of eye fundus, two sections on eye fundus periphery are pointed out, one of which is represented by unchanged retina, and state of the second section requires examination. Diagrams for pointed out sections of red and blue colours are built in 256 brightness gradations. By built diagrams medians of said colours are calculates. After that, ratio of red-colour median to blue-colour median is calculated. Obtained numerical values of red-colour median and blue-colour median ratios are compared to each other for unchanged and examined retina sections, and if obtained numerical value of ratio of red-colour medians to blue colour on examined section is less than on unchanged section of retina, presence of dystrophic changes in examined section is diagnosed.

EFFECT: method makes it possible to reduce time of eye fundus examination, diagnose all spread forms of peripheral dystrophic changes of retina, and also gives possibility to store obtained results and observe objectively the course of peripheral retina dystrophies in dynamics.

12 dwg, 3 ex

Description

The invention relates to medicine, namely to ophthalmology, and is intended for the diagnosis of dystrophic changes on the periphery of the fundus. The method can be used in all medical institutions involved in pathological changes in the periphery of the retina.

Known methods for digital evaluation of color photography of the fundus. These assessment methods can reliably diagnose the presence of pathological changes in the fundus. So, for example, there is a method for early diagnosis of the pathology of the optic nerve of the paired eye (Linnik L.F. et al., Patent No. 2130612, publication date 05/20/1999). The essence of this technique is to measure the parameters of the constituent primary colors. Charts of the distribution of these colors in the fundus image of the patient under study are constructed in 256 gradations of brightness. Determine the minimum, maximum, fashion and median of red and the range of green. The resulting distribution diagrams of the primary colors are compared with the reference diagrams according to the maximum similarity criteria. If the minimum of red color is less than 186, the maximum of red color is less than 237, the mode of red color is less than 228, the median of red color is less than 215, and the range of green color is less than 96, then the pathology of the optic nerve disk of the paired eye is diagnosed. The proposed method allows the creation of an objective reliable method for early diagnosis of the pathology of the optic nerve of the paired eye with the aim of timely pathogenetically directed treatment to preserve its visual functions. Unfortunately, this technique is not applicable for the diagnosis of peripheral retinal dystrophies, although, in our opinion, the proposed method is notable for its simplicity and reliability.

Currently, there is only one way to diagnose dystrophic changes on the periphery of the fundus: ophthalmoscopy is direct and indirect, using a Goldman lens on a slit lamp. All these methods allow you to examine the periphery of the fundus and in a descriptive form to record the results of the examination. It is important to note that the quality of fixation of an ophthalmological examination, even with a standardized approach, may differ from each other by different experts. Thus, the data obtained are not entirely objective and do not allow reliable assessment of dystrophic changes in the periphery of the retina in dynamics.

There is also another way to diagnose the type of course of peripheral vitreochorioretinal dystrophy (Pozdeeva OG Peripheral vitreochorioretinal dystrophy in university students. Vestnik Ophthalmology, 2003, No. 6, pp. 39-41).

This method is intended to determine the type of course (stable, progressive or complicated) of peripheral vitreochorioretinal dystrophy of the eye. The method is carried out by conducting ultrasound dopplerography of the vessels of the eyeball and orbit, in which the intensity and direction of glycolysis, as well as the activity of lipid peroxidation of cell membranes in tear fluid and blood serum are determined. With low blood flow in the orbital artery and central retinal artery, an increase in the characteristics of anaerobic glycolysis and lipid peroxidation, a stable course of the dystrophic process is diagnosed. When there are non-through retinal ruptures, the presence and / or appearance of fresh foci of dystrophy, an increase in the rate of blood flow in the orbital artery and central artery of the retina, as well as activation of lipid peroxidation with an increase in the concentration of products 3-4 times, a progressive course of the degenerative process is diagnosed. With a decrease in dopplerographic parameters against the background of an increase in the intensity of anaerobic glycolysis parameters and an increase in the intensity of lipid peroxidation, a complicated course of the dystrophic process is diagnosed. The method can be used to diagnose the course of peripheral dystrophic changes and does not allow to diagnose the types of peripheral dystrophic changes in the retina, which today causes certain difficulties. In addition, this method is complex, requires additional expensive equipment.

A known method for the differential diagnosis of dystrophic changes in the retina, namely, “whitening without suppression” and flat retinoschisis, by conducting trial laser coagulation, which is selected as a prototype (A. Semenov and co-authors of patent No. 2102916, publication date 01/27/1998).

The known method involves laser exposure using an argon laser to an unchanged retina near the area of chorioretinal dystrophy with an exposure of 0.05-0.1 s, a spot diameter in focus of 100-200 μm with a power of 0.06 W, gradually increasing the power to obtain laser coagulum I -II degree. After that, the chorioretinal dystrophy zone is affected with the same power and other parameters of argon laser radiation, and if similar laser I-II degree coagulants with clear boundaries, uniform color are formed, then peripheral chorioretinal dystrophy of the type “blanching without suppression” is diagnosed. If, when exposed to an altered part of the retina, to obtain laser coagulants I-II, an increase in radiation power is required compared with exposure to an unchanged part of the retina, and the resulting laser coagulates have fuzzy boundaries and / or a double contour and / or uneven color, then retinosis is diagnosed.

The disadvantages of this method include:

1. The ability to diagnose only two types of peripheral vitreochorioretinal dystrophic changes in the retina.

2. The need for laser coagulation of the retina in a healthy area of the periphery of the fundus.

3. The inability to make a differential diagnosis between “blanching without suppression” and a healthy portion of the retina.

The task was set: to develop a method for the diagnosis of dystrophic changes in the retina at the periphery of the fundus, allowing reliable and objective assessment of dystrophic changes in the retina at the periphery of the fundus.

The technical result consists in simplifying, reducing the time of the study, the possibility of an objective assessment and preservation of the results, preventing complications associated with damage to healthy parts of the retina, expanding the capabilities of the method by diagnosing all forms of dystrophic changes in the retina by digitally evaluating the color photograph of the fundus using empirically the indicator we defined.

Pathological changes in the fundus are characterized, most often, by a decrease in blood circulation of the retina. It is assumed that in digital photography, these changes will be characterized by a decrease in the red component and an increase in the blue component. Thus, the ratio of primary colors: red and blue.

The invention consists in the following.

To assess dystrophic changes in the fundus, an analysis of the obtained color digital photograph of the fundus is performed. Two areas are distinguished in the resulting image, one of which is represented by unchanged retinal tissue, and the state of the second needs to be investigated. The components of red and blue colors are determined for the image of two selected sections of the periphery of the retina, for which purpose the distribution diagrams of the indicated colors are constructed in 256 gradations of brightness. Next, for each selected area in the resulting image, the median of red and blue colors is determined from the presented diagrams and the ratio of the median of red to median of blue for each of the selected areas of the image is calculated. The presented relations are compared with each other and diagnosed with dystrophic changes in the studied area on the periphery of the retina, if the ratio of the median red to blue is less than that in the area represented by unchanged retinal tissue.

It is important to note that peripheral vitreochorioretinal retinal degeneration is a multifactorial and polyetiological disease characterized by complex pathophysiological changes in the tissues of the eye, including a violation of the blood supply to its membranes. During empirical studies, it was found that the ratio of red to blue can serve as an objective and highly informative indicator for diagnosing the development and progression of dystrophic changes in the fundus.

The method is as follows.

Double-expanding drops are instilled into the patient (in our case, midriacil 1%). The fundus is photographed 20 minutes after instillation of the drops. Photographing of the fundus is carried out, for example, on a KOWA VX-10 digital fundus camera. Having received a color digital image, it is possible to evaluate it using the Adobe photoshop program. To evaluate an unchanged area, as well as in a color image, it is isolated, for example, using the Magnetic Lasso Photoshop program tool, which allows you to select the desired area by the main significant (interesting) points. In the same way, a second portion of the retina is identified that requires investigation. Important elements for assessing the selected areas on the periphery of the retina are the medians of red and blue colors of the selected area, which are constructed in 256 gradations of brightness for each of the selected areas. Calculation of medians for red and blue colors according to diagrams is possible using the Adobe photoshop program. Next, the ratio of red to blue for the selected areas is calculated, one of which is the unchanged portion of the retina, and the second is required to be investigated, and the relations obtained are compared with each other. If the ratio of red to blue for the selected area of unchanged tissue is greater than this ratio for the studied area, then the presence of dystrophic changes in the studied area of the periphery of the retina is diagnosed.

The method is illustrated by the following figures:

The figure 1 presents a color digital image of the periphery of the fundus of the left eye with a selected area of unchanged retinal tissue.

The figure 2 presents diagrams of red and blue for the selected unchanged portion of the retina.

The figure 3 presents a color digital image of the periphery of the fundus of the left eye with a selected retina.

The figure 4 presents diagrams of red and blue colors for the selected study area of the retina.

The figure 5 presents a color digital image of the periphery of the fundus of the left eye with a selected area of unchanged retinal tissue.

The figure 6 presents diagrams of red and blue for the selected unchanged portion of the retina.

The figure 7 presents a color digital image of the periphery of the fundus of the left eye with a highlighted investigated portion of the retina.

The figure 8 presents diagrams of red and blue colors for the selected study area of the retina.

The figure 9 presents a color digital image of the periphery of the fundus of the right eye with a selected area of unchanged retinal tissue.

The figure 10 presents diagrams of red and blue for the selected unchanged portion of the retina.

The figure 11 presents a color digital image of the periphery of the fundus of the right eye with a highlighted investigated portion of the retina.

The figure 12 presents diagrams of red and blue colors for the selected study area of the retina.

We give specific clinical examples of the implementation of the proposed method.

Example 1

Patient K., 25 years old, turned to an ophthalmic clinical hospital with complaints of reduced vision in the distance. Diagnosis: mild myopia - both eyes; the right eye - dystrophy "trace of the cochlea", delimited by laser coagulation. Objectively: visual acuity of 0.08 without correction for both eyes, with full correction on the right eye sph-2,75cyl-0,5a × 78 ° = 1,0, on the left eye sph-2,0cyl-0,5a × l5 ° = 1.0. With a wide pupil, visual acuity without correction is 0.1, with full correction in the right eye sph-2.25cyl-0.25a × 78 ° = 1.0, in the left eye sph-l, 75cyl-0.25a × 15 ° = 1,0. The appendage is not changed. The cornea is transparent, the anterior chamber is of medium depth, the moisture is clean. The pupil in the center is round. The crystalline lens is transparent. Fundus ophthalmoscopy for mydriasis: both eyes are pale pink optic disc, borders are clear, disc excavation is physiological, myopic cone on the temporal side, arterial caliber slightly narrowed, venous gauge unchanged, dystrophy in the periphery of the right eye at 11 o’clock In the form of a “cochlear trace”, delimited by laser coagulation, on the periphery of the retina of the left eye during ophthalmoscopic examination, pigment redistribution was noted in the fundus, the macular area of both eyes was not changed. The patient was photographed in the fundus of the left eye using a digital fundus camera. In the obtained image of the periphery of the fundus of the left eye, an unchanged portion of the retina is highlighted (Fig. 1). Figure 2 presents diagrams for colors: red and blue, where the median for red is 255 and the median of blue is 49. Next, we calculate the ratio of medians of red to blue, respectively 255/49 = 5.2. Allocate the second investigated area of the retina (figure 3). The figure 4 presents the red diagrams for this selected area, for which the median is 255, and blue, the median of which is 74. Next, we calculate the ratio of the medians of red to blue for the selected modified portion of the retina - 255/74 = 3.4. The numerical value of the ratio of medians of red to blue for the selected study area is less than the numerical value of the ratio of red to blue for the area of unchanged retinal tissue: 5.2> 3.4. Therefore, dystrophic changes are diagnosed in the selected study area. This diagnosis is confirmed by a detailed ophthalmoscopic examination.

Example 2

Patient S., 30 years old, turned to an ophthalmic clinical hospital with complaints of reduced vision in the distance. Diagnosis: mild myopia, both eyes, right eye - PVCJ, delimited by laser coagulation. Objectively: visual acuity of 0.05 without correction for both eyes, with full correction on the right eye sph-1.75cyl-0.5a × 58 ° = 1.0, on the left eye sph-1.0sul-0.5a × 5 ° = 1.0. With a wide pupil, visual acuity without correction is 0.1, with full correction in the right eye sph-1,5cyl-0.25a × 58 ° = 1.0, in the left eye sph-0.75cyl-0.25al-5 ° = 1,0. The appendage is not changed. The cornea is transparent, the anterior chamber is of medium depth, the moisture is clean. The pupil in the center is round. The crystalline lens is transparent. Fundus ophthalmoscopy: both eyes - the optic disc is pale pink, the borders are clear, the excavation is physiological, the caliber of the arteries is somewhat narrowed, the caliber of the veins is not changed. The fundus was photographed using a digital fundus camera. On the resulting image, a section of unchanged retinal tissue is highlighted (Fig. 5) and diagrams for red and blue colors are constructed (Fig. 6). We calculate the ratio of medians of red to blue. In this case, the median of red is 213, and the median of blue is 35, so the ratio of red to blue is 213/35 = 6.0. We select on the presented image a portion of the retina that requires further research (Fig.7). We build diagrams of red and blue colors (Fig. 8), by which we determine their medians. The median for red is 161, the median for blue is 37. We calculate the ratio of medians of red to blue. The ratio of medians of red to blue was 161/37 = 4.4. When analyzing the numerical values of the ratios of the selected study area and unchanged retinal tissue, it turned out that the value of the median ratio for the unchanged portion of the retina (6.0) is greater than the median ratio for the selected studied area of the retina (4.4). Therefore, it is possible to diagnose the presence of dystrophic changes in a selected, investigated area. A detailed ophthalmoscopic examination in this area confirmed the presence of valvular rupture of the retina.

Example 3

Patient V., 35 years old, with myopia of moderate degree, turned to the ophthalmic clinical hospital for the next dynamic examination. Diagnosis: moderate myopia, both eyes, right eye - PVCRD, delimited by laser coagulation. Objectively: visual acuity is 0.03 without correction for both eyes, with full correction on the right eye sph-4.75 = 1.0, on the left eye sph-5.5 = 1.0. With a wide pupil, visual acuity without correction of 0.05, with full correction in the right eye, sph-4.25 = 1.0, in the left eye sph-4.5 = 1.0. The appendage is not changed. The cornea is transparent, the anterior chamber is of medium depth, the moisture is clean. The pupil in the center is round. The crystalline lens is transparent. Fundus ophthalmoscopy both eyes: the optic disc is pale pink, the borders are clear, the excavation is physiological, the myopic cone is on the temporal side, the caliber of the arteries is somewhat narrowed, the caliber of the veins is not changed. The patient underwent photographing of the periphery of the fundus. In the color image, a section of unchanged retinal tissue is highlighted (Fig. 9) and diagrams for red and blue colors are constructed (Fig. 10). According to the diagram, the median of red color is 202, of the blue color - 34, respectively, the numerical value of the ratio of red to blue is 5.9. Having selected a retinal area that requires further investigation (Fig. 11), using the indicated methodology, we calculate the ratio of the medians of red (194) to the median of blue (29) according to the diagrams presented in Fig. 12, we obtain a numerical value of 6.7. This value of the ratio of medians of red to blue is larger in value for the selected area with unchanged retinal tissue, which is 5.9. Therefore, there are no dystrophic changes in the selected study area, which was confirmed by a detailed ophthalmoscopic examination.

Thus, 70 eyes were analyzed with a digital color image of the periphery of the fundus. In all cases when dystrophic changes were diagnosed on the periphery of the retina during color analysis of a digital image using the proposed technique, these changes were also confirmed by a detailed ophthalmoscopic examination. In the study of the peripheral parts of the retina with the proposed method, it was possible to identify dystrophic changes in the form of a “snail trace” in 30 cases, “trellised” dystrophy in 15 cases, valve retinal tears in 10 cases and hole-like tears in 15 cases. It is important to note that the ophthalmoscopic examination of the patient took the researcher from 7 to 10 minutes. In the case of research by the proposed method - 3-5 minutes. Subsequently, the obtained data was stored in a database, and were also printed in the form of digital photographs and given to the patient. In addition to reducing research time, the proposed technique makes it possible to objectively examine and record changes in the periphery of the fundus, to save the image for a long time. Thus, the listed possibilities allow reducing the research time and reliably, objectively assess changes in the periphery of the fundus in dynamics.

Claims (1)

A method for diagnosing dystrophic changes in the retina at the periphery of the fundus, characterized in that a color image of the periphery of the fundus is obtained, two sections are selected on the image, one of which is represented by unchanged retinal tissue, and the condition of the second needs to be examined, the components of red and blue colors for the image are determined two selected sections of the periphery of the retina, for which build a diagram of the distribution of these colors in 256 gradations of brightness, then for each selected area on p the irradiated image, the median of red and blue colors is determined, the ratio of the median of red to the median of blue in each of the selected areas of the image is calculated, the obtained relations are compared with each other and diagnosed with dystrophic changes in the studied area at the periphery of the retina, if the ratio of medians of red to blue in it is less than that in the area represented by unchanged retinal tissue.

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