Biomechanical Properties of the Cornea Measured With the Dynamic Scheimpflug Analyzer in Young Healthy Adults

Purpose: To investigate the biomechanical properties of the cornea using the dynamic Scheimpflug analyzer in young healthy adults. Methods: This prospective cross-sectional population study included 944 eyes of 472 participants aged 20 to 40 years. Participants underwent ophthalmic investigations, including evaluation of biomechanical properties of the cornea using the dynamic Scheimpflug analyzer, manifest refraction, and measurements of keratometric values by autokeratometry, intraocular pressure (IOP) by noncontact tonometer, central corneal thickness (CCT) by ultrasound, and white-to-white distance by Scheimpflug tomography. Statistical analyses included determination of the reference interval with a bootstrapping method, linear quantile mixed-effects model, and Spearman correlation analysis between the corneal biomechanical parameters and other variables (age, manifest refraction spherical equivalent, CCT, IOP, white-to-white, and keratometric values). Results: The 90% CIs of all corneal biomechanical parameters demonstrated that the ranges of the 90% CIs for the reference data were almost identical with and without bootstrapping. Quantile regression to determine the fifth, 50th, and 95th percentiles of each corneal biomechanical parameter supported the findings from the nonparametric method with the 90% CIs. Correlation analysis showed significant correlations between the parameters and variables, but there was a relatively high Spearman correlation coefficient in the case of the correlations with the CCT and IOP. Conclusions: Using data from a large population of young healthy adults, we developed a database of normal values for multiple corneal biomechanical parameters obtained from the dynamic Scheimpflug analyzer. We conclude that the biomechanical properties of the cornea are influenced by the CCT and IOP.