The influence of the geometry of the porcine cornea on the biomechanical response of inflation tests.

To withstand the high probability of success, the growing diffusion of laser surgery for the correction of visual defects, corneal surgeons are regarding with interest numerical tools able to provide reliable predictions of the intervention outcomes. The main obstacle to the definition of a predictive numerical instrument is the objective difficulty in evaluating the in vivo mechanical properties of the human cornea. In this study, we assess the ability of a parametrised numerical model of the cornea (Pandolfi and Manganiello 2006) to describe individual pressurisation tests on whole porcine corneas once the mechanical parameters of the model have been calibrated over average data. We also aim at estimating the sensitivity of the mechanical response with the variation of basic geometrical parameters, such as the central corneal thickness, the curvature and the in-plane diameter. We conclude that the actual geometry of a cornea has a minor role in the overall mechanical response, and therefore the material properties must be considered carefully and individually in any numerical application. This study makes use of the data obtained from a wide experimental program, where a set of 21 porcine corneas has been fully characterised in terms of mechanical and geometrical properties (Boschetti et al. 2012).