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Introduction. Glaucoma is a socially significant disease. With the advent of new technologies it has become possible to diagnose this disease at an earlier stage. The aim of the investigation was to reveal the relationships between biomechanical parameters of the optic nerve disc (OND) in patients with primary open-angle glaucoma (POAG) against the background of achieving the "target" intraocular pressure (IOP). Material and methods. A retrospective cohort study was conducted in which 51 patients with POAG were included. All patients underwent a standard ophthalmologic examination. Central corneal thickness and biomechanical parameters of the cornea were also evaluated. Optical coherence tomography (OCT) was performed to assess the state of the OND. Results and discussion. Goldman IOP levels had no differences depending on glaucoma stage, but corneal compensated IOP levels differed: the lowest IOP was detected in patients with advanced glaucoma, and the highest – in patients with far advanced glaucoma. Corneal hysteresis factor (CH) and corneal resistance factor (CRF) values also depended on the glaucoma stage: the highest – in initial, the lowest – in far advanced glaucoma. The coefficient of biomechanical tension of the fibrous membrane of the eye was the highest in the group of patients with advanced glaucoma. When assessing the correlation between corneal biomechanical properties and OND parameters, there was a positive correlation of CTR with the mean thickness of RNFL, RNFL thickness in the upper segment and neuroretinal band area (NRB), and a negative – with horizontal, vertical size and excavation area. Conclusion. This investigation demonstrated the correlation between corneal parameters (CCT, CH, CRF) and their derivatives: CH/CRF ratio, corneal biomechanical tension coefficient and corneal biomechanical coefficient characterizing IOP compensation degree and morphological parameters of the optic disk in POAG against the background of "target" IOP. Protective properties of a thicker cornea, higher indices of corneal hysteresis and corneal resistance factor to glaucoma progression were shown. Keywords: glaucoma, corneal hysteresis, opti

PURPOSE. To evaluate the clinical utility of pattern electroretinography (PERG) in the differential diagnosis of ocular hypertension and newly diagnosed primary open-angle glaucoma (POAG) of the initial stage.METHODS. This prospective non-randomized cohort study included patients over the age of 35 years with newly diagnosed ocular hypertension and initial stage POAG in at least one eye. All patients underwent a standard ophthalmological examination, as well as a complex of additional methods used to diagnose POAG: pachymetry, examination of the biomechanical properties of the cornea (Ocular Response Analyzer, Reichert), standard automated perimetry (SAP) (Octopus 900, Haag-Streit Diagnostics), optical coherence tomography (OCT) of the optic nerve head (ONH) and macular area (OCT Triton Plus 3000, Topcon) and PERG (Diopsys Nova, Diopsys, Inc.). Data from both eyes of all included patients were analyzed (12 eyes in the ocular hypertension group and 26 eyes in the POAG group). Statistics was calculated using the StatPlus:mac Software package (StatPlus Inc., Taiwan).RESULTS. During this study we recorded statistically significant differences in steady-state PERG parameters according to the PERG-24 protocol (magnitude, magnitude D — taking into account the magnitude and variability of the response phase throughout the test — and their reverse ratio, determined at pattern contrasts of 100% and 85%) between the groups of patients with newly diagnosed ocular hypertension and newly diagnosed initial stage POAG with a comparable level of intraocular pressure, corneal thickness, biomechanical properties and comparable perimetric indices, as well as the average thickness of the retinal nerve fiber layer and the ganglion cell complex according to OCT data. At the same time, all PERG parameters in the ocular hypertension group were within the normal range, while individual PERG parameters in the POAG group had deviations from the normal.CONCLUSION. Steady-state PERG may be an additional objective method for early detection of disorders in the functioning of retinal ganglion cells (RGCs), which allows differential diagnosis of ocular hypertension without damage of RGCs and initial stage POAG. In addition, dynamic examination with steady-state PERG of individuals with ocular hypertension may allow early detection of the onset of retinal ganglion cells death, i.e. the development of POAG, than with SAP and OCT.