Enhancement After Myopic Small Incision Lenticule Extraction (SMILE) Using Surface Ablation

PURPOSE: To report the feasibility and outcomes of surface ablation after small incision lenticule extraction (SMILE). METHODS: In this retrospective evaluation of 1,963 SMILE procedures, 43 eyes (2.2%) were re-treated at three separate clinics. Of these, 40 eyes of 28 patients with a follow-up of at least 3 months were included in the analysis. During surface ablation, mitomycin C was applied for haze prevention. RESULTS: Spherical equivalent was -6.35 +/- 1.31 diopters (D) before SMILE and -0.86 +/- 0.43 D before surface ablation. Surface ablation was performed after a mean of 9.82 +/- 5.27 months and resulted in a spherical equivalent of 0.03 +/- 0.57 D at 3 months (P < .0001). The number of patients within +/- 0.50 and +/- 1.00 D of target refraction increased from 22.5% to 80% and from 72.5% to 92.5%, respectively. Mean uncorrected distance visual acuity (UDVA) improved from 0.23 +/- 0.20 to 0.08 +/- 0.15 logMAR (P < .0001); 65% of patients gained at least one line. Corrected distance visual acuity (CDVA) remained unchanged with 0.01 +/- 0.07 logMAR before versus -0.01 +/- 0.05 logMAR after re-treatment (P = .99). Six eyes (15.0%) lost one line of CDVA, but final CDVA was 0.00 logMAR in four and 0.10 logMAR in two of these cases. The safety and efficacy indices were 1.06 and 0.90 at 3 months, respectively. Three of the four surface ablation profiles (Triple-A, tissue-saving algorithm, and topography-guided) resulted in equally good results, whereas enhancement with the aspherically optimized profile (ASA), used in two eyes, resulted in overcorrection (+ 1.38 and + 1.75 D). CONCLUSIONS: Combined with the intraoperative application of mitomycin C, surface ablation seems to be a safe and effective method of secondary enhancement after SMILE. Due to the usually low residual myopia, the ASA profile is not recommended in these cases.