title: Short-term outcomes of small-incision lenticule extraction (SMILE) for low, medium, and high myopia.
abstract: OBJECTIVE
  To determine the safety, efficacy, and predictability of small-incision lenticule extraction at 6-month follow-up, depending on the level of the myopic refractive error. The surgeries were performed by a surgeon new to this technique.
  
  
  METHODS
  Seventy-one subjects with a mean age of 31.86 ± 5.57 years were included in this retrospective observational study. Subjects were divided into 3 groups depending on the preoperative spherical equivalent (SE): low group from -1.00 D to -3.00 D, medium from -3.25 D to -5.00 D, and high from -5.25 D to -7.00 D. Manifest refraction, corrected distance visual acuity (CDVA), and uncorrected distance visual acuity (UDVA) were measured before surgery and at 6 months after the treatment.
  
  
  RESULTS
  In total, 1.4% of the eyes lost 1 line of CDVA after the procedure, whereas 95.8% remained unchanged and 2.8% gained 1 line. A significant undercorrection (p = 0.031) was found in the high myopia group (median -0.50 D), whereas the low and medium groups remained near to emmetropia. In terms of efficacy, no statistically significant intergroup differences for postoperative UDVA (p = 0.282) were found. The vector analysis also showed undercorrection of the preoperative cylinder, even though the standard deviations decreased from 0.9 D in the x axis and 0.7 D in the y axis to 0.24 D and 0.27 D, respectively.
  
  
  CONCLUSIONS
  Small-incision lenticule extraction might be a safe, effective, and predictable procedure even for inexperienced surgeons. No differences in efficacy were found among myopia levels even though undercorrections were found for SE and cylinder in high myopia.
authors.affiliation:  Department of Ophthalmology (Qvision), Vithas Virgen del Mar Hospital, Almería - Spain.
authors.forename: Joaquín
authors.initials: J
authors.lastname: Fernández
authors.affiliation:  Department of Ophthalmology (Qvision), Vithas Virgen del Mar Hospital, Almería - Spain.
authors.forename: Almudena
authors.initials: A
authors.lastname: Valero
authors.affiliation:  Department of Ophthalmology (Qvision), Vithas Virgen del Mar Hospital, Almería - Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Martínez
authors.affiliation:  Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante - Spain.| Department of Ophthalmology (OFTALMAR), Vithas Medimar International Hospital, Alicante - Spain.
authors.forename: David P
authors.initials: DP
authors.lastname: Piñero
authors.affiliation:  Department of Ophthalmology (Qvision), Vithas Virgen del Mar Hospital, Almería - Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodríguez-Vallejo
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000601:surgery; D003319:Corneal Stroma / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008866:Microsurgery; D009216:Myopia / Q000145:classification / Q000601:surgery*; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult