title: Four-year observation of predictability and stability of small incision lenticule extraction.
abstract: BACKGROUND
  To investigate long-term refractive outcomes, wavefront aberrations and quality of life after small incision lenticule extraction (SMILE) for moderate to high myopia.
  
  
  METHODS
  A total of 26 patients (47 eyes) with preoperative mean spherical equivalent (SE) of -6.30 ± 1.47 diopters (D) who underwent SMILE were recruited. The measurements included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, wavefront aberrations, and quality of life.
  
  
  RESULTS
  At 4 years postoperatively, UDVA was better than or equal to 20/20 in 92 % of eyes. The efficacy index was 1.07 ± 0.16. 89 % of eyes were within ± 0.5 D of the intended refractive target. No eye lost any Snellen lines. The safety index was 1.16 ± 0.14. No significant changes of SE occurred among postoperative follow-ups at months 1, 3, 6 and years 1, 2, 4 (P > 0.05, Scheffe test). Higher-order aberrations, coma, spherical aberration and higher-order astigmatism increased postoperatively, and no significant changes of aberrations were detected among the 1-month, 6-month or 4-year follow-ups postoperatively (37 eyes). Compared to the spectacles group, the surgery group showed a significantly higher total score on quality of life (45.71 ± 2.61 vs 39.96 ± 3.56, P < 0.001).
  
  
  CONCLUSIONS
  SMILE provides a predictable and stable correction of moderate to high myopia as documented by long-term follow-up.
authors: Department of Ophthalmology and Vision Science, Eye and ENT Hospital of Fudan University, No.19 Baoqing Road, Xuhui District, Shanghai, China.
authors: Tian
authors: T
authors: Han
authors: Department of Ophthalmology and Vision Science, Eye and ENT Hospital of Fudan University, No.19 Baoqing Road, Xuhui District, Shanghai, China.
authors: Ke
authors: K
authors: Zheng
authors: Department of Ophthalmology and Vision Science, Eye and ENT Hospital of Fudan University, No.19 Baoqing Road, Xuhui District, Shanghai, China.
authors: Yingjun
authors: Y
authors: Chen
authors: Aier School of Ophthalmology, Central South University, Changsha, China.
authors: Yang
authors: Y
authors: Gao
authors: Department of Ophthalmology, UruTmqi Eye and ENT Hospital, No.387 Zhongshan Road, Urumqi, Xinjiang, China.
authors: Li
authors: L
authors: He
authors: Department of Ophthalmology and Vision Science, Eye and ENT Hospital of Fudan University, No.19 Baoqing Road, Xuhui District, Shanghai, China. doctzhouxingtao@163.com.
authors: Xingtao
authors: http://orcid.org/0000-0002-3465-1579
authors: X
authors: Zhou
mesh_terms: D000328:Adult; D048988:Corneal Surgery, Laser / Q000379:methods; D057108:Corneal Wavefront Aberration / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D011788:Quality of Life; D012029:Refraction, Ocular / Q000502:physiology; D054140:Refractive Surgical Procedures / Q000379:methods*; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
keywords: Aberrations; Quality of Life Impact of Refractive Correction (QIRC) questionnaire; Quality of life; Small incision lenticule extraction (SMILE)