Refraction and Visual Outcome between the Enhancement Methods on Regressed or Undercorrected Myopia after LASIK

ABSTRACT

PURPOSE: To evaluate refraction and visual outcome between the enhancement methods on regressed or undercorrected myopia after primary laser in situ keratomileusis (LASIK). METHODS: This prospective comparative study comprised 114 eyes of 114 patients who had enhancement between March 2003 and March 2004. A single surgeon performed all surgeries. Patients were subdivided according to enhancement methods lifting flap group (Group I), LASEK enhancement group (Group II) and tPRK group (Group III). Flap was lifted in 55 eyes and LASEK enhancement was performed in 23 eyes. tPRK was done in 36 eyes. Uncorrected visual acuity (UCVA), best-corrected visual acuity, refractive error was examined prior to, and 1 week and 1, 3, 6 months after enhancement. RESULTS: The mean time between initial LASIK and enhancement were 6.67+/-2.49 months in Group I, 7.86+/-5.23 months in Group II and 6.08+/-2.38 months in Group III. At POD 6 months, the mean postoperative UCVA were 0.96+/-0.14 (0.026+/-0.079 logMAR), 0.97+/-0.15 (0.016+/-0.078 logMAR) and 0.89+/-0.21 (0.079+/-0.196 logMAR) snellen equivalent respectively and this did not differ significantly (p=0.166). The mean spherical equivalents were -0.60+/-0.69D (diopter), -0.91+/-0.75D and -0.88+/-0.60D respectively at POD 6 months and this also did not differ significantly (p=0.172). CONCLUSIONS: All three enhancement methods were useful procedure for correcting residual refractive errors after the primary LASIK. They provided good UCVA, predictable results and few complications.