Biomechanics of the cornea

As refractive procedures involving the cornea have proliferated, concerns over the long-term stability and predictability of these procedures have occupied a more prominent role. The authors have applied the procedures and principles of mechanical engineering to mathematically model the cornea and we have used this approach to predict corneal behavior. Strip testing was utilized to measure nonlinear stress/strain relationships in human cornea and scleral tissue. Nonlinear isotropic finite element analysis was utilized to predict corneal behavior under simple insufflation of the globe. Nonlinear anisotropic finite element analysis was used to demonstrate stress patterns and refractive changes in radial keratotomy. The importance of these calculations, as they relate to corneal stability and predictability, is discussed.