Influence of some operational variables on the radial keratotomy operation.

AIMS To assess the contribution of the four major operational variables in the radial keratotomy operation (RK) to the correction of myopic eyes. To study the deformation of the cornea after the operation and provide some valuable references for clinical practice. METHODS The expression of the correction ratio has been deduced, which can be directly represent as the deformation ratio of the corneal radius after the operation. This allows for the numerical simulation of the RK operation. On the basis of the known biomechanical property of the cornea, by means of the finite element method, a series of computerised geometric and biomechanical models for the simulation of refractive surgery have been established. Some operational variables in the RK operation were analysed, and their influence on the operational outcome has been computed and systematically analysed. RESULTS AND CONCLUSION All of the four variables have a positive effect on the operational outcome. The greater the four variables are the more correction effects of myopia can be obtained. Because the four variables are interinfluential, the operational variables can be optimised to get the best result in order to meet patients' differing requirements.