Modern diagnostic capabilities in the assessment of glaucoma changes

Relevance Glaucoma is a progressive atrophy of the optic nerve, manifested by specific damage to the retinal ganglion cells (RGC). Quantitative methods for assessing the structure of the optic nerve head (ONH) are referred to as hardware studies, such as confocal laser scanning ophthalmoscopy (HRT), scanning laser polarimetry (SLP) and optical coherence tomography (OCT) [1–3]. HRT is a laser system that performs shooting and analysis of three-dimensional images of the fundus. The device analyzes the main indicators of the ONH: the area of ​​the NP, its volume, excavation parameters, and the thickness of the RNFL. There are three generations of HRT, of which the latest is the most advanced due to the presence of automatic functions. It received an analysis program - an indicator of the probability of glaucoma. The technique is based on a comparison of patient data with a mathematical model and indicates the probability of the initial stage of glaucoma. SLP allows for a targeted assessment of the thickness of the RNFL, which forms the optic disc. The mechanism consists of the passage of polarized light through the axons of the retinal ganglion cells, which bifurcates in two perpendicular planes due to the braking effect. This technique is a valuable tool for detecting glaucoma at early and advanced stages. However, according to the manufacturer's instructions, the likelihood of obtaining poor-quality results increases in the presence of high ametropia. OCT allows for an accuracy of 3–10 μm to assess the thickness of the RNFL and the retinal ganglion cell complex (RGC) [4]. The device automatically determines the boundaries of the structures, takes into account the angle of inclination of the optic disc. A circle with a diameter of 3.46 mm, centered relative to the disk, is assessed. The area of ​​the optic disc, NRP, excavation volume, excavation to optic disc ratio, and RNFL thickness graph are analyzed. The angiography mode as part of OCT is a new structural study. This method allows obtaining a three-dimensional image of the microcirculatory bed in a non-invasive manner. This allows for quantitative analysis with calculation of the density of the capillary network and avascular zones [5]. Conclusion Optical coherence tomography is the tool of choice among currently existing methods for diagnosing structural damage in glaucoma. Keywords: glaucoma; confocal scanning laser ophthalmoscopy; scanning laser polarimetry; optical coherence tomography; angiography