Small incision lenticule extraction versus photorefractive keratectomy: A comparative study

Purpose: The purpose of the study is to compare the objective and subjective quality of vision following small incision lenticule extraction (SMILE) and photorefractive keratectomy (PRK). We compared the postoperative safety, efficacy, predictability, refractive stability, contrast sensitivity, and spherical aberration changes in two groups over a 1-year follow-up period. Materials and Methods: This was a retrospective comparative study of 1-year duration. Fifty eyes of patients who underwent SMILE and 50 eyes of patients who underwent PRK were selected based on the inclusion and exclusion criteria. Methodology: Standard preoperative evaluation for all patients included corneal topography, refraction, anterior segment, retina evaluation, and intraocular pressure. Uncorrected visual acuity, best-corrected visual acuity, spherical aberration, and contrast sensitivity were measured preoperatively followed by 1, 3, 6, 9, and 12 months postoperatively. Results: Ninety-six percent of the eyes of patients who underwent SMILE and 92% of the eyes of patients who underwent PRK achieved postoperative refraction within ±0.5 D of the intended target refraction. No eyes in both the groups had any loss of visual acuity. Both procedures induced statistically significant spherical aberrations. However, the difference between the two groups was not statistically significant (P > 0.05). One hundred percent of eyes in SMILE and PRK group were noted to have a stable postoperative refraction till the last follow-up. Contrast sensitivity was better in eyes of patients who underwent SMILE comparing to PRK. Conclusion: Overall, both SMILE and PRK have shown excellent safety, efficacy, and predictability for correction of myopia and myopic astigmatism. SMILE is better in terms of refractive accuracy and quality of vision.