Long-term efficacy and safety profiles following small incision lenticule extraction in eyes with ≥ 5-year follow-up

Purpose: To evaluate long-term efficacy, safety, predictability and stability (refractive and keratometric) of myopic and myopic astigmatism correction with Small Incision Lenticule Extraction (SMILE). Methods: Single center retrospective review of eyes undergoing SMILE from 2012–2015. Forty-two eyes (23 patients) with ≥ 5-year follow-up. Variables analyzed were preoperative, 3-month, 1-year and last follow-up uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, spherical equivalent (SE) and mean keratometry. Descriptive statistics were performed and results reported following the Standard for Reporting Astigmatism Outcomes. Results: Mean follow-up of 5.98 ± 0.90 years. Mean preoperative SE was −5.26 ± 1.22D (range −2.50 to −8.12D). Mean preoperative cylinder was −0.66 ± 0.61D (range 0.00 to −2.25D). Efficacy and safety indices were 0.86 and 0.98, respectively. In total, 81% of operated eyes achieved an UDVA of ≥ 0.09 logMar (20/25 Snellen). At the last follow-up, ≥1 line of CDVA was gained in 14% of eyes. Five percent lost 1 line of CDVA, and no eye loss ≥2 lines of CDVA. Sixty-nine percent of eyes were within ± 0.50D and 86% within ± 1.00D of the attempted SE correction. Ninety-one percent of eyes had ≤0.50D of postoperative astigmatism and 71% were within ± 15° from the intended correction axis. At the final follow-up, a statistically significant myopic regression of 0.19 ± 0.50D was observed (p = 0.01). Conclusions: Long-term results demonstrate that SMILE is effective, predictable and safe. SMILE has good stability, low regression compared to LASIK, and no signs of corneal ectasia staging within our standard criteria.