7-Year Results of SMILE for High Myopia: Visual and Refractive Outcomes and Aberrations

PURPOSE: To evaluate the 7-year visual, refractive, and optical outcomes following small incision lenticule extraction (SMILE) for high myopia and myopic astigmatism. METHODS: Sixty-nine eyes (69 patients) undergoing SMILE between March 2011 and January 2012 at Aarhus University Hospital were included. Preoperative, 3-month, 3-year, and 7-year evaluation included: manifest refraction and uncorrected (UDVA) and corrected (CDVA) distance visual acuities, total corneal refractive power (TCRP), average keratometry (Km), aberrations, and central corneal thickness (CCT). RESULTS: Preoperative spherical equivalent averaged -7.53 +/- 1.18 diopters (D). Twenty-seven eyes were targeted emmetropia. In the emmetropic eyes, the postoperative logMAR UDVA remained stable (P = .11). When including all eyes, UDVA became worse from 3 to 7 years (3 months: 0.050 +/- 0.16 logMAR; 3 years: 0.044 +/- 0.21 logMAR; 7 years: 0.131 +/- 0.29 logMAR; P <.027), whereas CDVA remained stable (3 months: -0.07 +/- 0.09 logMAR; 3 years: -0.09 +/- 0.08 logMAR; 7 years: -0.09 +/- 0.08 logMAR, P >.99). At 7 years, 59.4% and 81.2% were within +/- 0.50 and +/- 1.00 D of target refraction, respectively. Average refractive regression was significant from 3 months to 7 years (-0.34 +/- 0.69 D) and from 3 to 7 years (-0.25 +/- 0.41 D, P <.05). After exclusion of three outliers with high myopic correction (< 9.63 D) and considerable regression (< -1.50 D), the average regression over 7 years was -0.25 +/- 0.49 D (P = .004) with no significant change from 3 to 7 years (P = .069). Average CCT, TCRP, and anterior Km significantly increased (P <.001), whereas the posterior Km and total corneal aberrations remained stable (P >.092). CONCLUSIONS: The long-term visual outcome remained stable after SMILE, but with an average regression of -0.34 D over 7 years. A minor group with high myopic correction exhibited considerable refractive regression years after SMILE.