Abstract
Huge effort has been concentrated on photorefractive keratectomy (PRK) studies, which would drastically improve current radial keratotomy (RK) method for correciton of miopia. Since ArF excimer laser ablation for cornea has been the brand-new technology in PRK, there have still many technical and/or physical problems which should be solved. I described the characteristics of current major PRK devices. The devices which were developed in early stage emit a uniform large aperture beam. In contrast, the latest devices emit a narrow non-uniform beam with scanning. It is difficult to judge which kind of devices have superiority. I think PRK device superiority is strongly depended on what kind of ablation is appropriate for PRK. I also explained the details of ablation parameters. The optimun conditions of some parameters are not well-known to estabish complication-free PRK. Humidity control of cornea surface and plume evacuation during laser irradiations are the most uncomprehended factors in conea ablation. The advantages of a large aperture ablation and/or multistep ablation are also unestablished. I think the optimum ablation to attain the complication-free PRK and the PRK device which is able to perform the optimum ablation should be studied.
