Evidence for Superior Efficacy and Safety of LASIK over Photorefractive Keratectomy for Correction of Myopia
Presented at: American Society of Cataract and Refractive Surgery Annual Symposium, March 2006, San Francisco, California.
Received 16 December 2005; accepted 9 August 2006.
Purpose
To examine possible differences in efficacy and safety between LASIK and photorefractive keratectomy (PRK) for correction of myopia.
Design
Meta-analysis/systematic review.
Participants
Patient 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.
Methods
A 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 Measures
Key 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).
Results
Seven 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).
Conclusions
LASIK 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.
Moorfields Eye Hospital, London, United Kingdom.
Correspondence and reprint requests to Dr Alex J. Shortt, Moorfields Eye Hospital, 162 City Road, London, EC1V 2PD, United Kingdom.
Manuscript no. 2005-1224.
The facilities used to conduct this study were provided by Moorfields Eye Hospital NHS Trust, London, United Kingdom.
1 Two of the authors (AJS, BDSA) derive a private practice income from refractive surgery but have no other financial interest in this topic or the article.
2 Dr Bunce has no financial interest in the subject matter.
ABSTRACT