Computer simulation of arcuate and radial incisions involving the corneoscleral limbus.

We have created a computer model of the eye that improves upon previous models with two assumptions: (1) the cornea is considered anisotropic, and (2) the strain tensor is non-linear for large displacements. Values used include those for Young's modulus, Poisson's ratio, and three coefficients of anisotropia. A finite element computer program was used to stimulate the behaviour of the eye. Four simulations were done: (1) a full thickness arcuate limbal cataract incision, (2) a partial thickness arcuate corneal relaxing incision, (3) a partial thickness radial incision extending across the limbus, (4) a partial thickness radial incision confined to the cornea. A full thickness corneal arcuate incision for cataract induced more change in corneal shape than a limbal incision. However, the gaping is more important in the limbal incision. Partial thickness arcuate corneal relaxing incisions were found to be more effective with a clear zone 3-5 mm in diameter. Radial incision simulation demonstrated little enhancement of the effect of the incisions when across the limbus.