Purpose: To assess the safety, efficacy, and predictability of femtosecond laser in situ keratomileusis (LASIK) in eyes with previous radial keratotomy (RK).
Setting: Hospital Virgen del Consuelo de Valencia, Valencia, and Vissum Instituto Oftalmológico de Alicante, Alicante, Spain.
Methods: This prospective study comprised 11 eyes of 7 patients with residual low myopia after previous RK who had surgery with the IntraLase femtosecond laser (IntraLase Corp.) and the Star 2 excimer laser (Visx, Inc.). Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), defocus equivalent, refraction, flap thickness, flap diameter, and intraoperative complications were evaluated over a minimum 6-month follow-up.
Results: Although the RK incisions opened in all eyes when the flap was lifted, LASIK was successfully completed in all cases. Mean flap thickness was 119 microm +/- 13 (SD). There were no cases of slipped flaps, microstriae, or epithelial ingrowth. Defocus equivalent was reduced from a mean of 2.51 +/- 0.62 diopters (D) to 0.52 +/- 0.28 D; 7 eyes (63.6%) were within +/-0.50 D, and 11 eyes (100%) were within +/-1.00 D. All eyes had 20/40 or better UCVA, although 2 eyes (18.1%) lost 1 line of BSCVA.
Conclusions: The femtosecond laser was safely used to create thin LASIK flaps in eyes with previous RK. An increased postoperative inflammatory response may explain the loss of BSCVA in some cases. Efficacy and predictability of the procedure were comparable to those of LASIK after RK with mechanical microkeratomes.