The excimer laser for corneal refractive surgery—recent developments and evolutionary directions

摘要

This article reviews recent developments in excimer laser refractive corneal surgery. The excimer laser is now used to treat myopia, hyperopia and astigmatism by either surface (photorefractive keratectomy or PRK) or stromal (laserin situkeratomileusis or LASIK) ablation. The refractive outcome of PRK is excellent for low (less than six dioptres) myopia, but it is not without complications. These include initial severe pain, myopic regression, haze, glare, halos and difficulty with vision in reduced light. The refractive outcome for LASIK is similar to that for PRK, but there is negligible pain, much less haze, less regression among highly myopic patients and a more rapid establishment of final unaided visual acuity.Although excimer laser treatment is currently available, some important advances are necessary before the spectacle and contact lens markets are threatened. Control of the healing process is crucial to improve the accuracy of the outcome, reduce regression and eliminate haze. More attention must be paid to the visual outcome and ablation design so that visual functions, such as best corrected visual acuity and contrast sensitivity, are not reduced. It even may be possible, in the future, to custom design aspheric ablations to yield improved best corrected visual acuity.