Anvil-profiled penetrating keratoplasty: load resistance evaluation

The aim of this study was to qualitatively evaluate the biomechanical load resistance of different surgical wound configurations (mushroom, zig-zag, anvil and conventional trephination) in penetrating keratoplasty (PK) by designing a 2D and a 3D finite-element biomechanical model of the cornea. A mathematical model of the human cornea was developed, and different geometric configurations for PK were designed. The internal pressure was raised until the wound misaligned; wound prolapse then occurred. Better wound resistance was found in all the laser trephined profiles tested in comparison with the conventional straight one. The anvil profile was more resistant to the increasing internal pressure than was the mushroom or the zig-zag pattern. Thanks to its greater mechanical load resistance, the anvil profile made possible the apposition of a restricted number of sutures and early suture removal. These advantages can contribute to a faster visual recovery in patients undergoing penetrating keratoplasty.