Long-term refractive outcomes and stability after excimer laser surgery for myopia

Abstract

Purpose: To evaluate the long-term refractive outcomes of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) for myopia. Setting: Centre for Eye Research Australia, Melbourne, Australia. Design: Comparative case series. Methods: Preoperative baseline refractions in eyes having PRK, LASIK, or both at 1 multisurgeon center were analyzed from patient databases. Two- to 13-year follow-up data were analyzed and compared with 1-month postoperative visual outcomes. Results: The study evaluated 389 eyes (229 patients). In the PRK group, the mean preoperative spherical equivalent (SE) was -4.05 diopters (D) ± 1.17 (SD) in eyes with low to moderate myopia and -7.97 ± 2.00 D in eyes with high myopia (P = .009) and in the LASIK group, -3.98 ± 1.27 D and -7.64 ± 1.66 D, respectively (P = .008). At the last visit, the mean SE in the PRK group was -0.64 ± 0.83 D in eyes with low to moderate myopia and -1.06 ± 1.74 D in eyes with high myopia (P = .73) and in the LASIK group, -0.33 ± 0.59 D and -0.63 ± 0.90 D, respectively (P = .68). At the end of the study, 45.9% of eyes with low to moderate myopia and 25.0% with high myopia in the PRK group and 64.8% and 37.3%, respectively, in the LASIK group were within ±0.50 D of the attempted correction. Conclusions: Laser refractive surgery effectively treated all levels of myopia. Refractive stability was achieved within 1 year postoperatively, with LASIK showing better stability than PRK for up to 6 to 9 years.