The goal of this research is to develop measurement tools and simulation technology for characterizing and predicting individual responses to corneal treatments and for advancing understanding of corneal ectasia risk factors. Patients who either 1) have keratoconus and are being evaluated for corneal crosslinking or 2) have refractive error and are being evaluated for refractive surgery procedures such as LASIK will have their eyes imaged to assess their mechanical properties and will have computational simulations performed to predict the response to treatment. One aim of the study is to test the hypothesis that computational models can predict the cornea's shape changes within clinically acceptable limits of error.