Advances in in vivo Measurement Methods for Ocular Biomechanical Material Properties

The cornea, sclera, and optic nerve head (ONH) are critical tissues for maintaining ocular structural integrity and visual function. In recent years, glaucoma, keratoconus, and high myopia have been confirmed to be closely associated with biomechanical alterations in these tissues. This review summarizes the main approaches for in vivo measurement of ocular biomechanical material properties. Externally induced direct measurement methods have established relatively mature index systems, but their results are often affected by intraocular pressure and corneal thickness. Non-loading direct measurement methods offer advantages in patient comfort and safety, yet remain limited by signal attenuation and noise. Patient-specific indirect inversion methods enable individualized, nonlinear, and anisotropic material property identification, showing particular values in the evaluation of the sclera and ONH, though their high model complexity and computational demands restrict clinical feasibility. Overall, in vivo measurement is advancing with improvements in imaging technologies, computational power, and the synergistic development of artificial intelligence and multimodal approaches, and its clinical values are expected to become increasingly prominent.