title: Dry Eye after Small Incision Lenticule Extraction (SMILE) versus Femtosecond Laser-Assisted in Situ Keratomileusis (FS-LASIK) for Myopia: A Meta-Analysis.
abstract: OBJECTIVE
  To compare dry eye after small incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK (FS-LASIK) for correcting myopia.
  
  
  METHODS
  CENTRAL, Embase and PubMed were searched in November 2016. All randomized controlled trials (RCTs) and prospective cohorts that compared dry eye after SMILE with FS-LASIK were selected.
  
  
  RESULTS
  Five cohorts and one RCT were identified for comparing dry eye after SMILE (291 eyes) and FS-LASIK (277 eyes). The pooled results revealed that the SMILE and FS-LASIK groups did not differ significantly in terms of Schirmer's I test (SIT) and tear film osmolarity (TFO) at any postoperative visits. By contrast, tear break up time (TBUT; p = 0.04 for one month, p < 0.001 for three months, and p = 0.02 for six months) and ocular surface disease index (OSDI; p < 0.001 for one month and three months, and p = 0.006 for six months) were significantly worse in the FS-LASIK group than in the SMILE group at follow-up. At six months postoperatively, TBUT and TFO values in both the SMILE and FS-LASIK groups and OSDI scores in the SMILE group returned to preoperative levels, but SIT values in both groups (p = 0.02 for the SMILE group and p < 0.001 for the FS-LASIK group) and OSDI in the FS-LASIK group (p < 0.001) were still statistically impaired.
  
  
  CONCLUSIONS
  Dry eye after both SMILE and FS-LASIK usually occurs transiently. SMILE does not show obvious superiority over FS-LASIK by exhibiting similar and acceptable objective parameters, and SMILE may have milder subjective symptoms.
authors.affiliation: Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Zeren
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Song
authors.affiliation: Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yan
authors.affiliation: Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Yao
mesh_terms: D048988:Corneal Surgery, Laser / Q000009:adverse effects* / Q000379:methods* / Q000706:statistics & numerical data; D015352:Dry Eye Syndromes / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects* / Q000379:methods / Q000706:statistics & numerical data; D054018:Lasers, Excimer / Q000009:adverse effects; D009216:Myopia / Q000453:epidemiology* / Q000601:surgery*