PARAMETRIC STUDIES OF RETINAL STRAIN DISTRIBUTION DUE TO REPAIR STENT USING FINITE ELEMENT MODELLING

摘要

A new retinal reattachment procedure was reported, and consisted of a procedure where the detached retina tissue was gently pressed in place by a self-expanding stent made of shape memory alloy (SMA). In the current work, the research focused on understanding the mechanical interaction among stent and neighboring human eyeball tissues (retina, choroid and sclera), on more accurately determining strain distribution in the repaired eye and on investigating the effect of stent geometry on the retinal strain distribution. The modelling was performed using finite element analysis (FEA). The tissues were modeled mostly with hyperelastic material models in order to predict strain distributions on retina and the rest of the eye tissues due to stent placement. The FEA model contained the representative eyeball tissues: retina, choroid, sclera, cornea, zonular fibers, lens, and ciliary muscle. The FEA simulations, were performed for several stent geometric configurations (number of loops, wire diameter, intraocular pressure etc.). The parametric studies demonstrated that stent configurations could be successfully designed so that the maximum strain levels would be below a permanent damage strain threshold of 2%.