Large Population Outcomes of Small Incision Lenticule Extraction in Young Myopic Patients

Abstract

PURPOSE: To evaluate the outcomes of small incision lenticule extraction (SMILE) for myopia in a large population of young adults. METHODS: In this retrospective case series, the patient population consisted of the first 4,138 consecutive SMILE treatments using the VisuMax femtosecond laser (Carl Zeiss Meditec) between 2012 and 2018 at the London Vision Clinic. Inclusion criteria were myopic spherical equivalent up to -9.00 diopters (D), cylinder up to 6.00 D, corrected distance visual acuity of 20/20 or better, age younger than 40 years, and follow-up of 12 months. Outcomes analysis was performed using the Standard Graphs for Reporting Refractive Surgery. RESULTS: Data were available at 12 months in 3,722 eyes (90%), and 416 eyes (10%) were lost to follow-up. Mean attempted spherical equivalent refraction (SEQ) was −4.61 ± 1.84 D (range: −1.12 to −9.00 D). Mean cylinder was −0.78 ± 0.66 D (range: 0.00 to −6.00 D). Postoperatively, the mean SEQ relative to target was −0.13 ± 0.30 D (range: −1.35 to +1.25 D) and was within ±0.50 D in 88.1% and ±1.00 D in 99.6% of eyes. Uncorrected distance visual acuity was 20/20 or better in 95.4% of eyes and 20/25 or better in 98.7% of eyes. One line of CDVA was lost in 3.0% of eyes, and 0.08% (n = 3) lost two or more lines of CDVA, for which CDVA was restored following phototherapeutic keratectomy treatment. There was a statistically significant improvement of 0.05, 0.06, 0.07, and 0.07 log units for contrast sensitivity at 3, 6, 12, and 18 cycles per degree, respectively ( P < .001). CONCLUSIONS: SMILE achieved excellent outcomes for myopia up to −9.00 D with cylinder up to −5.50 D for a large population in patients without presbyopia. [ J Refract Surg . 2022;38(8):488–496.]