[Excimer retreatment for undercorrection or regression after laser in situ keratomileusis].

To evaluate the results of excimer retreatment for undercorrection or regression after laser in situ keratomileusis (LASIK).Eight-eight eyes received retreatment for undercorrection or regression after first LASIK (FLASIK) in 2 149 eyes in our photorefractive keratotectomy (PRK)/LASIK center from March, 1996 to July, 1999. They were divided into 2 groups according to their degrees of pre-FLASIK myopia spherical equivalents. Group I was 10.00 D (47 eyes). We analyzed the factors of FLASIK which led to the re-LASIK (RLASIK), and observed the mean spherical equivalents (MSE), the ratio within +/- 1.00 D of emmetropia, the uncorrected visual acuity (UCVA), the best corrected visual acuity (BCVA) and the complication after RLASIK for at least 1 year follow-up study.The retreatment ratio was 4.1% among the 2 149 eyes. In group II, the ratio was 2.3 times that of the group I. In the comparison with other eyes, the eyes received RLAISK had no difference in sex, laterality and age (P > 0.05). Over 50.0% had pre-FLASIK diopters >/= 10.00 D, and 73.9% had astigmatism correction in FLASIK. After RLASIK, no undercorrection or regression occurred in group I, but there was undercorrection in group II. The ratio within +/- 1.00 D of emmetropia after 1 year was 68.3% in group I and 51.1% in group II. The UCVA above 0.5 was over 90.0% in all eyes. Eight eyes (9.0%) lost two or more lines of BCVA. The serious complication after RLASIK was keratoconus of 3 eyes in group II.The risk factors which lead to retreatment after FLASIK are high myopia with astigmatism before FLKSIK and the reaction to the operation. In this study, RLKSIK is safe, effective, predictable and accurate for -10.00 D in FLASIK.