Modeling the Cornea During Laser Ablation Procedures

Abstract

Photorefractive keratectomy (PRK) is a form of laser eye surgery used to correct vision. This procedure entails the precise removal of corneal tissue by laser ablation. It has been shown experimentally that dehydration of the corneal tissue leads to a higher dry mass ablation rate, which can lead to longer healing times and imprecise reshaping. In order to maximize surgical accuracy, it is important to know the relationship between tissue ablation rate and corneal hydration. Our model used the computational design software COMSOL 5.1 to model corneal heat and hydration levels during a simulated PRK procedure. We simulated heat and mass transfer under the specified conditions of the eye and laser. Although simplifications must be made from reality, computer-aided modeling allows us to obtain approximate results difficult to obtain in vivo. Consequently, the theoretical corneal hydration after removal of the epithelium and during laser ablation heating can be visualized. This model will be useful alongside experimental trials for improving the success of laser eye surgeries. This model was validated and showed high levels of consistency with past work and other simulations of the cornea during similar procedures. Additionally, this paper proposes one method that may be used to optimize laser ablation procedures by creating a constant ablation rate throughout the procedure. Further work may include finer time steps for time convergence, finer laser pulses, and a longer procedure time.