Corneal geometry determines optical quality, and its mechanical structure in turn determines its shape. In some corneal pathologies, such as keratoconus, a mechanical failure of the corneal structure compromises its geometry resulting in poor optical quality. Measurement of corneal mechanical properties is key in the understanding of pathologies, such as keratoconus, and their treatment (collagen cross-linking or intracorneal ring segments). In general, the ability of providing a measure of the corneal biomechanical properties in vivo would very valuable in identifying candidates for corneal treatments and monitor the outcomes.
We have developed new methods to measure corneal biomechanical properties in intact eyes ex vivo, and in patients in vivo that capitalize on quantitative imaging technologies and new mechanical models . These methods include whole eye corneal deformation inflation, and air-puff corneal deformation imaging (Scheimpflug-based, such as Corvis by Oculus, or dynamic-imaging based). In combination with custom developed finite element models we have obtained inherent mechanical parameters (Young modulus and time constants) in vivo and ex vivo, in normal eyes and eyes treated by UV-Riboflavin cross-linking. Also, we have collaborated with groups at the University of Murcia and Wellman Center of Photomedicine (Harvard-MGH) in technologies to assess corneal mechanical structure and biomechanical properties normal and cross-linked corneas, including microscopy-based techniques (second harmonic generation and Brillouin) and OCT vibrography.