3D Solid Incompressible Viscoelastic Finite Element in Large Strains for the Cornea.Refractive Surgery Application.

FABIO ARIEL GUARNIERI Y ALBERTO CARDONA

MECANICA COMPUTACIONAL

AMCA

Lugar: Tucumán; Año: 1996 vol. 16 p. 33 - 42

Several models[1,2,3,4] have been developed in otder to reproduce the corneal behavior in ophthalmologicd procedures as tonometry, radial keratotomy and photokeratectomy with Excimer Laser. It has been found that the viscoelastic effect of a biological soft tissue, as the cornea, is negligible in tonometry[5]. Nevertheless, clinical studies on humans showed refractive changes xith time in radial keratotomy. Wonnd healing is responsible for the long time effect (measured , in years). On the other hand, the short-time effect (hours or days) has not been clarified. In this work a 31) viscorlastic finite element model is developed taking into account incompressibility and large strains. An internal ~aria~bilse i ntroduced by means of a multiplicative decomposition of the deformation gradient. The final goal of the study is to determinate the importance of the viscoelastic effect in radial keratotomy.