title: Comparison of dry eye and corneal sensitivity between small incision lenticule extraction and femtosecond LASIK for myopia.
abstract: OBJECTIVE
  To investigate the changes in dry eye symptoms and clinical signs and corneal sensitivity after small incision lenticule extraction (SMILE) and femtosecond LASIK (femto-LASIK).
  
  
  METHODS
  Prospective, non-randomized comparative study.
  
  
  METHODS
  The study included a total of 71 eyes of 71 patients; the SMILE group comprised 38 eyes of 38 patients, and the femto-LASIK group comprised 33 eyes of 33 patients. Ocular Surface Disease Index (OSDI), Tear film breakup time (TBUT), the Schirmer test without anesthesia (S1T), corneal fluorescein staining, and central corneal sensation were evaluated before surgery and at 1 week, 1 month, 3 months, and 6 months after surgery.
  
  
  RESULTS
  OSDI scores in both groups were increased immediately and returned to preoperative level at 1 month after surgeries. The TBUT values in both groups were reduced after surgeries relative to their preoperative scores. Patients in SMILE group were less likely to have corneal staining compared with those in the femto-LASIK group ([odds ratio] OR = 0.50, 95% [confidence interval] CI 0.28 to 0.93, P = 0.03). Central corneal sensitivity was decreased at all postoperative time points in both groups. However, the central corneal sensation scores in the SMILE group were greater than that in the femto-LASIK group at all of the postoperative time points (all P<0.05).
  
  
  CONCLUSIONS
  SMILE surgeries resulted in a short-term increase in dry eye symptoms, tear film instability, and loss of corneal sensitivity. Furthermore, SMILE surgeries have superiority over femto-LASIK in lower risk of postoperative corneal staining and less reduction of corneal sensation.
authors.affiliation: Department of Ophthalmology, Eye and Ear Nose and Throat Hospital of Fudan University, Myopia Key Lab of the Health Ministry, Shanghai, China.
authors.forename: Meiyan
authors.initials: M
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.forename: Yang
authors.initials: Y
authors.lastname: Shen
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: He
authors.forename: Hailin
authors.initials: H
authors.lastname: Xu
authors.forename: Yongfu
authors.initials: Y
authors.lastname: Yu
authors.forename: Xingtao
authors.initials: X
authors.lastname: Zhou
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D003315:Cornea / Q000503:physiopathology*; D015352:Dry Eye Syndromes / Q000503:physiopathology*; D005260:Female; D019793:Fluorescein; D005500:Follow-Up Studies; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer; D008297:Male; D009216:Myopia / Q000503:physiopathology* / Q000601:surgery; D011379:Prognosis; D011446:Prospective Studies; D012677:Sensation / Q000502:physiology*; D013524:Surgical Flaps
chemical_list: D019793:Fluorescein