Purpose: To compare long-term clinical outcomes between photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK).
Methods: Forty-three eyes of 22 patients undergoing PRK and 36 eyes of 18 patients undergoing conventional LASIK were followed for ≤4 years. Uncorrected visual acuity, best-corrected visual acuity, and manifest refractive spherical equivalent were compared over short-term (≤1 year) and long-term (1-4 years). As potential factors affecting refractive changes, central corneal thickness and posterior corneal elevation were also investigated.
Results: Over short-term, LASIK was superior to PRK in terms of uncorrected visual acuity and best-corrected visual acuity. However, PRK was superior to LASIK over long-term. Manifest refractive spherical equivalent of PRK was stable, whereas regression was observed with LASIK. Central corneal thickness of LASIK was significantly larger than that of PRK at 4 years postoperatively, whereas there was no difference of posterior corneal elevation after the 2 procedures.
Conclusion: Superiority of LASIK over PRK at short-term observation did not persist thereafter, mainly because of myopic regression occurring with long-term follow-up.