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

Abstract

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.

Dynamic Scheimpflug Ocular Biomechanical Parameters in Untreated Primary Open Angle Glaucoma Eyes

“…The results of this study agreed with our previous study that showed greater compliance of medially treated glaucoma eyes. 23 A comparison of parameter values between our previous study and the current study revealed that corneal deformability of medically treated glaucoma eyes were larger than that of untreated glaucoma eyes. This finding raises the possibility that medical treatment makes glaucoma eyes even more deformable.…”

“…32 These results are similar to the results of our previous study. 23 In addition, ROC analyses suggest the potential discriminative capability of some of the biomechanical parameters. The results of the current study give insight into the biomechanical aspects of glaucoma, and could contribute to the future development of new diagnostic and treatment strategies for the disease, possibly by combining the best performing biomechanical parameters into a simple combined index.…”

“…16,17,22 In a previous study, we demonstrated the greater compliance of glaucoma eyes compared with healthy eyes after controlling for these confounding effects. 23 However, because most previous studies, including ours, enrolled glaucoma patients under medical treatment, the question remains unanswered as to whether biomechanical alterations in glaucoma eyes were caused by glaucoma per se, medications for glaucoma, or both.…”

Age distribution and associated factors of cornea biomechanical parameter stress-strain index in Chinese healthy population

“…Corneal biomechanical determination is of great importance in clinical evaluation, such as diagnosis of keratoconus [ 1 ], assessment before corneal refractive surgery [ 2 , 3 ], and measurement of corrected intraocular pressure [ 4 , 5 ]. In recent years, various instruments that measured corneal biomechanics were developed, such as ocular response analyzer (ORA) and Corvis ST.…”

Age Distribution and Associated Factors of Cornea Biochemical Parameter Stress-Strain Index in Chinese Healthy Population

“…Corneal biomechanical determination is of great importance in clinical evaluation, such as diagnosis of keratoconus 1 , assessment before corneal refractive surgery 2,3 , and measurement of corrected intraocular pressure 4,5 . In recent years, various instruments that measured corneal biomechanics appeared, such as ocular response analyzer (ORA) and Corvis ST.…”