Finite-element modeling of intrastromal ring segment implantation into a hyperelastic cornea

摘要: PURPOSE. Intrastromal corneal-ring segments (ICRSs) are applied to improve highly distorted vision in keratoconic, myopic, and astigmatic patients. Selections of ICRS geometry position primarily based on empirical nomograms. We developed a finite-element model (FEM) predicting the corneal response different geometries normal keratoconic corneas. METHODS. A two-dimensional FEM was built proprietary software (ANSYS-APDL), consisting hyperelastic ocular tissues (cornea, limbus, sclera) triangular/hexagonal poly(methyl methacrylate). An incrustation considering local material addition rigidity increase at also for triangular geometric difference between its base (plane) tunnel (parallel surface). Different heights (150‐350 lm) optical zones (4.4‐6.6 mm) were simulated. axis-symmetric keratoconus studied, where elasticity decreased locally. RESULTS. (height zone) had significant influence power: changes from 4.08 � 17.7 diopters (D) (healthy)/3.31 20.5 D (keratoconic) observed. Central thickness predicted by up 38.5 lm (healthy)/97.9 (keratoconic). Spherical aberration changed upon implantation. The protrusion posterior cornea behind rings well predicted. confirmed clinically reported trends effect ring geometry. CONCLUSIONS. is powerful tool study combination with individual biomechanical properties patients holds promise predictability surgery. (Invest Ophthalmol Vis Sci. 2013;54:881‐889) DOI:10.1167/ iovs.12-10852