title: Safety and complications of more than 1500 small-incision lenticule extraction procedures.
abstract: OBJECTIVE
  To evaluate the safety and complications of small-incision lenticule extraction (SMILE).
  
  
  METHODS
  Clinical control cohort study.
  
  
  METHODS
  A total of 922 healthy patients (1800 eyes) who were treated for myopia or myopic astigmatism between January 2011 and March 2013 at the Department of Ophthalmology, Aarhus, Denmark.
  
  
  METHODS
  Patients received a full preoperative examination and were treated with SMILE in both eyes and followed for 3 months (1574 eyes). Patients with complications, including loss of corrected distance visual acuity (CDVA) or dissatisfaction, were offered a late reexamination.
  
  
  METHODS
  Surgical complications and CDVA.
  
  
  RESULTS
  Mean preoperative spherical equivalent refraction was -7.25±1.84 diopters (D). Average postoperative refraction was -0.28±0.52 D, and mean error of treatment was -0.15±0.50 D. By 3 months, 86% (1346 eyes) had unchanged or improved CDVA. A loss of 2 or more lines was observed in 1.5% of eyes; however, at a late follow-up visit (average, 18 months), CDVA was within 1 line of the preoperative level in all eyes. Perioperative complications included epithelial abrasions (6%), small tears at the incision (1.8%), and difficult lenticule extraction (1.9%). The cap was perforated in 4 eyes, and a major tear occurred in 1 eye; however, none of these patients had late visual symptoms. In 0.8% (14 eyes), suction was lost during surgery. Re-treatment was successful in 13 eyes, whereas 1 eye had ghost images and was re-treated with topography-guided photorefractive keratectomy (PRK). Postoperative complications included trace haze (8%), epithelial dryness on day 1 (5%), interface inflammation secondary to central abrasion (0.3%), and minor interface infiltrates (0.3%); these complications had an impact on CDVA at 3 months in only 1 case. Irregular corneal topography occurred in 1.0% of eyes, resulting in reduced 3-month CDVA (12 eyes) or ghost images (6 eyes). Topography-guided PRK was performed in 4 eyes, with improvement in 3 cases. Satisfaction was high, with only 2 patients dissatisfied at their latest visit because of blurred vision or residual astigmatism.
  
  
  CONCLUSIONS
  Overall, SMILE had acceptable safety. Although 1.5% of eyes had reduced CDVA by 3 months, visual acuity was restored in the long term. Likewise, patient satisfaction was high.
authors.affiliation: Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: ai@dadlnet.dk.
authors.forename: Anders
authors.initials: A
authors.lastname: Ivarsen
authors.affiliation: Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Sven
authors.initials: S
authors.lastname: Asp
authors.affiliation: Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Jesper
authors.initials: J
authors.lastname: Hjortdal
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery*; D015331:Cohort Studies; D003319:Corneal Stroma / Q000601:surgery*; D048988:Corneal Surgery, Laser / Q000009:adverse effects / Q000379:methods*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D054018:Lasers, Excimer / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008866:Microsurgery / Q000379:methods; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D017060:Patient Satisfaction; D011183:Postoperative Complications; D012029:Refraction, Ocular / Q000502:physiology; D041623:Tomography, Optical Coherence; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult