Laser in situ keratomileusis to correct myopia, hypermetropia and astigmatism after penetrating keratoplasty for keratoconus: a series of 27 cases.

BACKGROUND: Excimer laser treatment has been shown to be effective and safe in correcting anisometropia following penetrating keratoplasty (PKP). In this report we review our experience with excimer laser in situ keratomileusis (LASIK) to correct refractive myopia, hypermetropia and astigmatism in patients who had undergone PKP for keratoconus. METHODS: We reviewed the records of 22 patients (27 eyes) who had undergone LASIK to correct myopia, hypermetropia or astigmatism, in simple or combined forms, following corneal transplantation for keratoconus. LASIK was performed at a hospital in Curitiba, Brazil, between September 1998 and February 2000. The eyes were classified into two groups: those with a negative spherical equivalent and those with a positive spherical equivalent. LASIK was performed using the Moria LSK microkeratome and the Nidek EC-5000 excimer laser. RESULTS: The mean length of follow-up was 9.52 months for the 23 eyes with myopia and 5.75 months for the 4 eyes with hypermetropia. The mean refractive spherical equivalent in the myopic eyes was -5.27 (standard deviation [SD] 1.91) dioptres before LASIK and -0.45 D (SD 1.68 D) at the last follow-up visit. The corresponding values in the eyes with hypermetropia were +5.18 D (SD 1.46 D) and + 1.18 D (SD 0.94 D). The rate of regression of astigmatism in the myopic eyes was 76%. After surgery 18 (78%) of the myopic eyes and all the hypermetropic eyes had an uncorrected visual acuity of 20/40 or better. The best spectacle-corrected visual acuity was better than 20/25 in 22 (95.7%) of the myopic eyes and all the hypermetropic eyes. One eye lost 1 line of best spectacle-corrected Snellen visual acuity, and one eye lost 6 lines secondary to epithelial ingrowth. Wound dehiscence, intraoperative flap complications, graft rejection or other complications did not develop in this series. INTERPRETATION: In this series, LASIK proved to be relatively safe and effective in correcting refractive errors after PKP for keratoconus.