Clinical Results of LASIK Enhancement

PURPOSE: To assess the results of laser in situ keratomileusis (LASIK) enhancement by lifting the original flap and reablation for the treatment of myopic regression and undercorrection after initial LASIK. METHODS: We analyzed LASIK enhancement results in 19 patients (27 of 1026 eyes) which had myopic regression or undercorrection after initial LASIK. We evaluated the changes of refractive error, uncorrected visual acuity, best corrected visual acuity, corneal topography, and corneal thickness before and six months after enhancement. We also analyzed enhancement rate according to the original refractive error. RESULTS: Overall, the mean spherical equivalent (SE) was -7.10+/-1.78 diopters (D) before LASIK, -2.80+/-0.79D prior to enhancement and -0.31+/-0.46D at 6 months after enhancement (p<0.001). The uncorrected visual acuity at 6 months after enhancement was 1.0 or better in 10 eyes (37.0%) and 0.5 or better in 27 eyes (100%). Best corrected visual acuity (BCVA) did not change in 12 eyes (44.4%) and improved 1 line or more in 9 eyes (33.3%) at 6 months after enhancement. The final refractive error of one group which underwent enhancement within postoperative 3 month was closer to emmetropia than that of the other which had enhancement after postoperative 3 month, but there was no statistically significant difference (p=0.589). CONCLUSIONS: LASIK enhancement by using the original flap was an effective procedure, if the changes of refractive error were stable on refraction or corneal topography.

Clinical result of myopic LASIK enhancement

PURPOSE: To evaluate the predisposing factors for enhancement and assess the efficacy of LASIK enhancement using a technique of lifting the flap for residual myopia after laser assisted in situ keratomileusis (LASIK). METHODS: 46 eyes that underwent LASIK enhancement by lifting the flap using the same excimer laser as primary LASIK were retrospectively studied for the predisposing factors for enhancement and the efficacy of LASIK enhancement for residual myopia. LASIK of 20 eyes were performed by STAR and 26 eyes by Mel 70. RESULTS: The higher the initial spherical eqivalent (SE) and keratometer, the larger the amount of undercorrection (p<0.05), and the higher the initial SE and the change of corneal thickness during regression, the larger the amount of regression (p<0.01). There was no difficulty during lifting the flap regardless of time after primary LASIK and no complication during or after enhancement. The SE before and after enhancement was -2.38+/-0.86 D and -0.93+/-0.87 D. Uncorrected visual acuity was 20/25 or better in 80% of eyes. CONCLUSIONS: LASIK enhancement by lifting the flap for correctable residual myopia after primary LASIK was relatively easy to perform and effective for correction of residual myopia.