In vivo detection of human corneal stiffness and mechanical anisotropy with high-frequency guided-wave optical coherence elastography

Understanding corneal biomechanics is crucial for improving refractive surgery, detecting abnormalities, and assessing intraocular pressure. However, measuring corneal biomechanics in vivo is challenging due to limited spatial resolution and the difficulty in measuring tensile moduli. To address these challenges, we developed high-frequency guided-wave optical coherence elastography (OCE) to detect symmetric (S0) and anti-symmetric (A0) elastic waves in healthy and keratoconic corneas in vivo. This technique allows high-resolution stiffness mapping, and simultaneous measurement of both tensile and shear moduli. Our results show a notable transverse stiffness gradient from the peripheral to the central cornea. In addition, we demonstrate that the in vivo human cornea is highly anisotropic and exhibit opposite age-dependency trends for the tensile and shear moduli. Our OCE technique promises to be a valuable clinical tool for quantitative corneal biomechanics assessment.