Relationship between corneal biomechanical indexes and optic disc morphometric indexes in patients with primary open angle glaucoma

Abstract

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