Evidence for Superior Efficacy and Safety of LASIK over Photorefractive Keratectomy for Correction of Myopia

PurposeTo examine possible differences in efficacy and safety between LASIK and photorefractive keratectomy (PRK) for correction of myopia.DesignMeta-analysis/systematic review.ParticipantsPatient data from previously reported prospective randomized controlled trials (PRCTs) and a systematic review of prospective case series in the Food and Drug Administration (FDA) clinical trials database.MethodsA comprehensive literature search was performed using the Cochrane Collaboration methodology to identify PRCTs comparing LASIK and PRK for correction of myopia. A meta-analysis was performed on the results of PRCTs. In parallel, a systematic review of prospective data from FDA case series of LASIK and PRK for correction of myopia was undertaken.Main Outcome MeasuresKey efficacy outcomes (uncorrected visual acuity [UCVA] ≥ 20/20, ±0.50 diopters [D] of the target mean refractive spherical equivalent) and safety outcomes (loss of ≥2 lines of best spectacle-corrected visual acuity [BSCVA], final BSCVA ≥ 20/40, and final BSCVA < 20/25 where preoperative BSCVA was ≥20/20).ResultsSeven PRCTs were identified comparing PRK (683 eyes) and LASIK (403 eyes) for correction of myopia. More LASIK patients achieved UCVA ≥ 20/20 at 6 months (odds ratio, random effects model [95% confidence interval], 1.72 [1.14–2.58]; P = 0.009) and 12 months (1.78 [1.15–2.75], P = 0.01). Loss of ≥2 lines of BSCVA at 6 months was less frequent with LASIK (2.69 [1.01–7.18], P = 0.05). Data from 14 LASIK (7810 eyes) and 10 PRK (4414 eyes) FDA laser approval case series showed that more LASIK patients achieved UCVA of 20/20 or better at 12 months (1.15 [1.03–1.29], P = 0.01), significantly more LASIK patients were within ±0.50 D of target refraction at 6 months (1.38 [1.26–1.50], P<0.00001) and 12 months (1.21 [1.08–1.36], P = 0.0009) after treatment, and loss of ≥2 lines of BSCVA at 6 months was less frequent with LASIK (2.91 [2.22–3.83], P<0.00001).ConclusionsLASIK appears to have efficacy and safety superior to those of PRK. However, the data examined are from studies conducted ≥5 years ago. It is therefore unclear how our findings relate to present-day methods and outcomes. Further trials comparing contemporary equipment and techniques are needed to reevaluate the relative merits of these procedures.