Custom Surgical Design for Intrastromal Rings

FABIO A GUARNIERI

Ft Lauderdale

Conferencia; ARVO 2011 Meeting; 2011

ARVO

Purpose:To evaluate the performance of a computer program that simulates the intrastromal rings surgery in keratoconics eyes Methods:A computer model of the biomechanics of the cornea is presented based on the Finite element method. The cornea is modelled as a 3D, anisotropic, nonlinear and heterogeneous material. The lamellae and its mechanical behavior with the matrix is taking into account in the model, both for normal and keratoconus corneas. Ferrara rings are simulated and analyzed. The pre and post corneal topographies of a Ferrara rings surgery using PENTACAM are compared with the simulation. Results:By comparing the elevation map preop and postop both positive and negative elevations are reduced both in real surgery and simulations. Reduction of irregular astigmatism is obtained by changing the position of the rings as seen in the simulation of the corneal topography. Conclusions:The computational model can integrate the biomechanical behavior of the cornea and the implants with data obtained from bioinstrumentation (corneal topography, pachymetry, tonometry, corneal aberrometry).The computational biomechanical model of the interaction between the keratoconic cornea and ISRs can predict the topographic changes after surgery.This model can help in the customized planning of the ISRs surgery and creation of new nomograms that can reduce irregular astigmatism and improve the prediction of the refractive surgery.