Increasing corneal curvature by RF current: numerical model studies of governing physical processes

摘要

The cornea may be reshaped to correct hyperopia by selective shrinkage of collagen in the stroma using radio Frequency (RF) current from a needle electrode. Continuous sine wave current at constant power has proven very effective to achieve repeatable results by thermally shrinking corneal collagen. Post-treatment relaxation of the collagen may be moderated by creating a larger zone of lesser damage over a longer heating time; rather than using a smaller zone of greater damage created in a shorter time. Finite difference numerical models of the electric fields and resulting thermal events were used to study the process parameters and to identify advantageous treatment strategies. The models include temperature- and water-dependent electrical and thermal properties.