Method for determining shape of optic nerve disc depression

Abstract

FIELD: ophthalmology.SUBSTANCE: used for objective differential diagnostics of the anatomical form of the optic nerve disc (OND) deepening. Optical coherence tomography is performed on the Optovue RTVue XR Avanti System using the 3D Disc program. Images of the optic disc are obtained in the horizontal plane, a straight line is drawn between the visible boundaries of the retinal pigment epithelium (RPE) and the position and shape of the bottom of the OND deepening are assessed. When the depression is at the level of the RPE and the angle of its bottom is less than or equal to 90° a triangular shape is defined. If the depression is located above the RPE level and the angle of its bottom is more than 90° a flat shape is defined. If the depression is below the RPE level and the bottom angle is less than or equal to 90° a wedge shape is defined. If the depression is below the RPE level, and its bottom forms a base and two angles, a trapezoidal shape is defined.EFFECT: improving the accuracy, objectivity and reproducibility of determining the individual anatomical shape of the OND excavation by using a stable anatomical landmark – the RPE and standardized geometric parameters, which eliminates subjective error in diagnosis.1 cl, 7 dwg, 1 tbl, 3 ex

Description

[0001] The invention relates to the field of medicine and biology, namely to anatomy and ophthalmology, and can be used in the practice of ophthalmologists, pathomorphological laboratories of medical institutions and morphological departments of higher educational institutions of medical and biological profile.

[0002] Optical disc examination using optical coherence tomography allows for reliable qualitative and quantitative characterization of both the optic disc itself and its structural elements. The proposed classification method provides a clear understanding of the optic disc depression shape and allows for differential diagnosis of diseases that alter the anatomical characteristics of the optic disc, which is essential for improving the efficiency of diagnostic testing in ophthalmology and pathology. The method is safe for the patient and simple for the examiner.

[0003] Technology Level

[0004] There are no data in the literature on the classification of normal optic disc depression shapes. There is evidence that changes in the optic disc depression shape may indicate the development of diseases. For example, according to S.I. Zhukova, one of the criteria for glaucoma progression is the development of glaucomatous excavation of the optic disc, which indicates a change in the shape of the optic disc depression. According to A.N. Kramarenko, with optic disc edema, the arrangement of nerve fibers changes, leading to a change in its anatomical shape (the optic disc depression may be completely absent).

[0005] There is a known method for assessing atypical shapes of the optic nerve head based on ophthalmoscopic imaging, which distinguishes between vertical-oval and oblique-vertical shapes of the optic nerve head [Tarutta E.P., Markosyan G.A. State of the fundus in children and adolescents with congenital myopia / / Modern possibilities in diagnostics and treatment of vitreoretinal pathology. - Collection of works of the scientific and practical conf. - Moscow, 2004. - Pp. 332-333]. However, a disadvantage of the proposed method for assessing the shape of the disc is the lack of assessment of the shape of the optic nerve head depression, which is key in making diagnoses and differentiating diseases.

[0006] There is a method for classifying the shapes of the optic nerve head depression. The method for assessing atypical shapes of the optic nerve head was used (RU 2361505, authors V.P. Erichev, A.I. Akopyan, published on July 20, 2009). In this method, the classification of the optic nerve head shapes is carried out according to several parameters: 1. Transverse disc, the ovality index of which was from 0.5 to 0.75; 2. Longitudinal disc, the ovality index of which was greater than 1.35; 3. Inclined disc, with an inclination in the horizontal axis of> 300 μm; 4. A large round disc, the area of ​​which was greater than 3.0 mm 2 in combination with an ovality index of 0.75-1.35; 5. Round disc with a large excavation - optic disc area of ​​1.5 mm 2 - 3.0 mm 2 in combination with an ovality index of 0.75-1.35 and an excavation area greater than 0.5 mm 2 ); 6. Prominent disk with an excavation area of ​​no more than 0.05 mm 2 in combination with a minimum value of the optic nerve head contour line of no more than 0.1 mm.

[0007] The disadvantage of the proposed method is that atypical forms of the optic nerve disc are analyzed.

[0008] Similar to our classification method is the study of the forms of the optic disc deepening according to several anatomical parameters, the grouping of which determines the form of the optic disc deepening.

[0009] The purpose of creating a method for determining the shape of the optic nerve head depression was to create a simple and understandable morphological classification to improve the efficiency of diagnostic studies, facilitate diagnosis and reduce the number of errors associated with overdiagnosis of certain diseases.

[0010] The novelty of this method lies in the authors' proposal of an original method for determining the shape of the optic disc depression. This method aims to improve the efficiency of diagnostic tests, facilitate diagnosis, and reduce errors associated with overdiagnosis of certain diseases. This classification method is based on the morphological characteristics of the optic disc, is applicable to all age groups, and is technically simple to use. These shapes represent normal variants.

[0011] Technical result

[0012] The technical result of the proposed method is to increase the efficiency of diagnostic studies, facilitate diagnosis and reduce the number of errors associated with overdiagnosis of glaucoma and optic disc edema in the absence of complaints from the patient.

[0013] Essence of the invention

[0014] The method for determining the shape of the optic disc depression includes the following: obtaining a picture of the optic disc in the horizontal plane, drawing a straight line between the visible boundaries of the retinal pigment epithelium and assessing the position and shape of the bottom of the optic disc depression: if the optic disc depression is at the level of the retinal pigment epithelium and its bottom forms an acute angle (less than 90°) or a right angle (equal to 90°), then this shape is considered triangular; if the optic disc depression is above the level of the retinal pigment epithelium and its bottom forms an obtuse angle (more than 90°), then this shape is considered flat; if the optic disc depression is below the level of the retinal pigment epithelium and its bottom forms an acute angle (less than 90°) or a right angle (equal to 90°), then this shape is considered wedge-shaped;If the depression of the optic nerve head is located below the level of the retinal pigment epithelium and its bottom forms a base and two angles, then this shape is considered trapezoidal.

[0015] Implementation of the invention

[0016] The examination is performed on the Optovue RTVue XR Avanti System using the standard 3D Disc software. The patient sits in a chair, stabilizes their head, and then focuses their gaze on a flashing dot. The tomograph operates by measuring the time it takes for a beam of light reflected from a particular optical section (A-scan) to return to the device. A series of A-scans performed on all structures in the examined area allows for reconstruction of both the anterior and posterior segments of the eye in a cross-sectional plane. Images of these cross-sections are called B-scans.

[0017] After the examination, the computer analyzes the obtained data and displays the corresponding images on the monitor. After obtaining an image, a straight line is drawn in the horizontal plane between the visible boundaries of the retinal pigment epithelium (indicated in red) and the position and shape of the optic disc fossa are assessed (Figs. 1-7).

[0018] The shape of the optic disc recess is considered triangular (Fig. 1) if the optic disc recess (1) is at the level of the retinal pigment epithelium (2) and its bottom forms an acute angle (less than 90°) or a right angle (equal to 90°), then this shape is considered triangular.

[0019] The shape of the optic disc recess is considered flat (Fig. 2) if the optic disc recess (1) is located above the level of the retinal pigment epithelium (2) and its bottom forms an obtuse angle (more than 90°), then this shape is considered flat.

[0020] The shape of the optic disc recess is considered wedge-shaped (Fig. 3) if the optic disc recess (1) is located below the level of the retinal pigment epithelium (2) and its bottom forms an acute angle (less than 90°) or a right angle (equal to 90°), then this shape is considered wedge-shaped.

[0021] The shape of the optic disc recess is considered trapezoidal (Fig. 4) if the optic disc recess (1) is below the level of the retinal pigment epithelium (2) and its bottom forms a base and two angles, then this shape is considered trapezoidal.

[0022] Also, the forms of the optic nerve head deepening are presented in Table 1.

[0023]

[0024] Usage example.

[0025] Patient S., 9 years old. No complaints. Requested a professional examination. Vis OU = 1.0. Evaluation of optical coherence tomography data yielded the following image (Fig. 5). Drawing a line connecting the retinal pigment epithelium (2), we find that the fundus of the optic disc recess (1) is located below this line, and two angles are visible within it. This shape was assessed as trapezoidal.

[0026] Patient A., 32 years old. No complaints. Requested a professional examination. Vis OU = 1.0. Evaluation of optical coherence tomography data yielded the following image (Fig. 6). Drawing a line connecting the retinal pigment epithelium (2), we find that the bottom of the optic disc fossa (1) is located below this line, and the shape of its bottom has an acute angle (less than 90°). This shape was assessed as wedge-shaped.

[0027] Patient B., 80 years old. Complaints of low vision in the right eye. Phacoemulsification of cataract with implantation of an intraocular lens was performed. Postoperative Vis OD = 1.0. Evaluation of optical coherence tomography data yielded the following image (Fig. 7). Drawing a line connecting the retinal pigment epithelium (2), we find that the fundus of the optic disc fossa (1) is located at the level of the retinal pigment epithelium, and the shape of its fundus has an acute angle (less than 90°). This shape was assessed as triangular.

[0028] Thus, the proposed classification method increases the efficiency of diagnostic studies, facilitates diagnosis and reduces the number of errors associated with overdiagnosis of certain diseases.

[0029] When using this method, the following positive effects are achieved:

[0030] - morphological approach to the forms of optic nerve head deepening.

[0031] - the ability to easily and simply determine the shape of the optic nerve disc depression without resorting to additional instruments.

[0032] - ease of differential diagnosis of certain diseases that may manifest asymptomatically in the early stages.

[0033] Bibliography

[0034] 1. Patent RU 2361505 “Method for assessing atypical forms of the optic nerve head” (Authors: Erichev V.P., Akopyan A.I., published 2009).

[0035] 2. Tarutta E.P., Markosyan G.A. State of the fundus in children and adolescents with congenital myopia / / Modern possibilities in diagnostics and treatment of vitreoretinal pathology. - Collection of works of the scientific and practical conf. - M., 2004. - P. 332-333.

[0036] 3. Zhukova, S.I. Optical coherence tomography in diagnostics and monitoring of congenital and juvenile glaucoma / S.I. Zhukova, T.N. Yuryeva / / Acta Biomedica Scientifica (East Siberian Biomedical Journal). - 2022. - V. 7, No. 2. - P. 147-166.

[0037] 4. Kramarenko, AH Congestive optic disc congestion: a problem of modern ophthalmology, neurology and neurosurgery / A.N. Kramarenko, I.P. Maryenko / / Neurology and neurosurgery. Eastern Europe. - 2023. - Vol. 13, No. 1. - P. 66-76.

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