Inverse Estimation of the In Vivo Mechanical Properties of the Human Cornea

Various forms of refractive surgery for vision correction have come into clinical practice in which the corneal tissue is either incised, removed, added to, or redistributed. The outcomes of these procedures must be to a large extent determined by the intrinsic mechanical properties of the major structural layer of the cornea, the stroma1. If these mechanical properties, principally the Young’s modulus and shear modulus, are established for the human cornea, it will be possible to include them in a finite element model of the stroma that can help predict the outcome of keratorefractive procedures. In this study an opto-mechanical testing device was developed to measure the contour of a cornea deformed in situ by a mechanical probe. A nonlinear finite element model of the cornea was then constructed to simulate the experiment for use in inverse estimation of the in vivo Young’s and shear moduli of an individual eye.