Dynamic Scheimpflug Ocular Biomechanical Parameters in Healthy and Medically Controlled Glaucoma Eyes

Purpose: To evaluate the relationship between biomechanical parameters measured with a dynamic Scheimpflug analyzer and glaucoma. Patients and Methods: Cross-sectional observational data of 47 eyes of 47 consecutive subjects with medically controlled primary open-angle glaucoma and 75 eyes of 75 healthy subjects examined with a dynamic Scheimpflug analyzer (Corvis ST) were retrospectively investigated. Eight biomechanical parameters were compared between eyes with and without glaucoma using multivariable models adjusting for intraocular pressure (IOP), central corneal thickness, age, and axial length. Results: In multivariable models, glaucoma was negatively correlated with A1 time (P<0.001, coefficient=-0.5535), A2 time (P=0.008, coefficient=-0.1509), radius (P=0.011, coefficient=-0.4034), and whole eye movement (P<0.001, coefficient=-0.0622). Negative correlation between glaucoma and 3 parameters (A1 time, A2 time, and radius) consistently indicate larger deformability of the cornea and negative correlation between glaucoma and whole eye movement indicate smaller eye movement, in glaucoma eyes. There were significant correlations of many biomechanical parameters with other baseline factors (8 parameters with IOP, 2 with central corneal thickness, 4 with age, and 7 with axial length). Conclusions: Eyes with medically controlled glaucoma were more deformable than healthy eyes, which may increase the risk of optic nerve damage through an underestimation of IOP and biomechanical vulnerability of the globe. Many parameters showed a significant correlation with baseline factors, suggesting the importance of adjustment for these confounding factors when evaluating the correlation between biomechanical parameters and ocular diseases. These results suggest the relevance of measuring biomechanical properties of glaucoma eyes for accurate IOP measurement and risk assessment.