In order to prevent the development of central island after excimer laser photorefractive keratectomy(PRK), 547 eyes which had undergone PRK were studied to evaluate the incidence, width and height of central island retrospectively. Based on this result, PRK was performed on 63 eyes under conventional protocol(software version 3.20, VISX Twenty/twenty Inc, Santa Clara, CA) and then additional laser ablation with a correction amount of 2.5D and adiameter of 3mm was performed whether the incidence has been decreased and additional complications have occurred. As a result of conventional protocol, central island had occurred in 121 eyes out of 547(22.1%) and the width was 2.94+/-0.22mm and the height was 2.64+/-0.89D. In case of 63 eyes which underwent additional laser ablation, central island occurred in 4 eyes (6.34%) and overcorrection occurred only in 3 eyes(4.76%) at one month after PRK. From the standpoint of the above results, we reached the conclusion that the additional ablation for 2.5D by a 3mm in diameter after PRK under conventional protocol is effective. By using this method, we could reduce the incidence of central island without the aid of the upgraded version that contains the anti-central island program.
Incidence ; Laser Therapy ; Lasers, Excimer* ; Myopia* ; Photorefractive Keratectomy* ; Retrospective Studies