Speaker
Description
The quantitative assessment of biomechanical properties of ocular tissues remains a significant challenge, primarily due to the limited availability of non-contact, high-resolution techniques capable of probing localized mechanical responses in vivo. In particular, the cornea exhibits complex viscoelastic behavior governed by its microstructural organization, and its mechanical properties are closely linked to physiological function and pathological conditions such as ectasia. The approaches, coupling acoustic radiation force excitation with optical detection of tissue motion, provide a promising framework for localized elastography with micrometer-scale sensitivity. In this study, we demonstrate a method for stiffness characterization of thin soft tissues, combining focused air-coupled ultrasound excitation with phase-sensitive optical coherence tomography (OCT). Localized mechanical perturbations are induced via acoustic micro-tapping (AμT), in which a focused ultrasonic transducer generates a transient acoustic radiation force at the tissue surface, launching surface (Rayleigh-type) waves. The resulting nanometer-scale displacements are captured using OCT, enabling depth-resolved tracking of wave propagation with high temporal and spatial resolution.The proposed approach was validated using gelatin-based phantoms with controlled elastic properties, as well as ex-vivo corneas. Shear wave velocities were estimated from spatiotemporal displacement fields and subsequently used to reconstruct the effective Young’s modulus of the samples. The results demonstrate differentiation of stiffness across phantoms and confirm the feasibility of the method for thin, layered biological tissues. This work highlights the potential of optical and ultrasound methods for non-invasive, high- resolution assessment of corneal biomechanics. The presented methodology is particularly suited for ophthalmic applications, where precise characterization of mechanical properties may support early diagnosis of corneal pathologies and improve patient-specific treatment planning.