The Central Island Occurrence Rate and Correlation between the Central Island and Corrected Visual Acuity after Excimer Photorefractive Keratectomy According to the Myopia Degree

ABSTRACT

We examined 60 eyes of 60 patients after excimer photorefractive keratectomy(PRK) for myopia and analyzed the changes of central island on corneal topography for 6 months prospectively. These patients were divided into two groups according to the degree of myopia, group 1(26 eyes, 6 diopters or below by spherical equivalent) and group 2 (34 eyes, over 6 diopters). The occurrence rate of central island was 76.4% collectively, 87.5% in group 1, 67.7% in group 2 at 2 weeks after PRK. It decreased to 30.4%, 43.5%, and 21.1% respectively at 6 months after PRK and was lower in group 2 than group 1. However there was no statistically significant correlation between the reduction of central island size and improvement of corrected visual acuity in both groups. In conclusion, the central island disappeared and decreased the amount for six months follow-up period after PRK and seems to be no effect on the corrected visual acuity.