Stratified corneal densitometry and biomechanical properties in human eyes: A Scheimpflug analysis

This study characterized the in vivo association between stratified corneal densitometry and depth-dependent biomechanical properties by integrating data from the Pentacam Scheimpflug system and dynamic deformation parameters obtained with the corneal visualization Scheimpflug technology (Corvis ST), thereby providing novel insights into in vivo corneal biomechanics. Sixty-four myopic patients underwent corneal imaging with both devices. Corneal densitometry was divided into anterior, middle, and posterior layers using Pentacam; the overall corneal elastic modulus was determined from Corvis ST outputs. Depth-dependent corneal elastic modulus variations were modeled using exponential, logarithmic, and polynomial functions, with the optimal model selected based on published experimental data. Layer-specific elastic moduli were subsequently calculated from these data. The ratios of layer-to-total densitometry (R_D) and layer-specific-to-total corneal elastic moduli (R_E) were calculated. Both R_D and R_E showed anteroposterior decreases trends (P < 0.05), with a positive correlation between them (r = 0.887, P < 0.001). These findings indicate that spatial variations in corneal densitometry reflect underlying depth-dependent biomechanical heterogeneity, supporting stratified densitometry as a potential surrogate for assessing regional corneal mechanical properties in clinical Scheimpflug analysis.