Abstract
Current situation of corneal refractive surgery and clinical results of photorefractive keratectomy (PRK) by excimer laser were discussed. The surgical methods to correct refractive error have been developed and their main object is cornea which has the largest refractive power in the optical system of the eye. The change of corneal shape can change refractive power. But cornea has very peculiar tissue characteristics to maintain its optical specificity. Any surgical attempts involve possibilities to damage its characteristics. Radial keratotomy of the peripheral cornea may cause weakning of the cornea and postoperative various unfavourable visual complaints. Recently developed cold laser, excimer laser with 193 nm wave length can remove corneal tissue and was applied to refractive surgery. The method is to ablade center of the cornea in optically designed lens shape by computer-assisted manipulation. This PRK method enables us to have a better predictability and less tissue damage than the other methods. However, PRK has still problems such as postoperative transient ocular pain, long standing corneal haze and fractuation of visual acuity in some cases.
