Visual and Refractive Efficacy of Photorefractive Keratectomy and Femto-small Incision Lenticule Extraction in Myopia: A Systematic Review and Meta-analysis

Abstract Background: Myopia (near sightedness) is a common refractive error treated with corrective lenses or refractive surgery. Photorefractive keratectomy (PRK) and small incision lenticule extraction (SMILE) are widely used surgical procedures. While both are effective, limited comparative research exists. Objective: This systematic review and meta analysis aim to evaluate which procedure offers better visual outcomes, correction, and safety in myopic patients. Methods: Following PRISMA guidelines, literature was searched in Web of Science, Cochrane Library, PubMed, and Scopus. Data on uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent (SE), and higher order aberrations (HOAs) were extracted and analyzed. Results: Meta analysis of 13 studies (1990 patients, 3980 eyes) showed SMILE significantly improved UDVA and SE compared to PRK. The mean difference (MD) for UDVA was 0.02 (95% confidence interval [CI] [0.01–0.03], P = 0.002), and standardized MD for SE was 0.30 (95% CI [0.08–0.51], P = 0.006). SMILE also improved total coma (MD 0.04, 95% CI [0.01–0.08], P = 0.01) and spherical aberration (MD 0.07, 95% CI [0.01–0.14], P = 0.03). No significant differences were found in CDVA, HOAs, target induced astigmatism, surgically induced astigmatism, or correction index. Conclusion: Both PRK and SMILE are effective for myopia correction. SMILE may offer modest advantages in certain visual quality metrics, but results should be interpreted cautiously due to study heterogeneity. Further randomized trials are needed to guide clinical recommendations.