title: Confocal comparison of corneal reinnervation after small incision lenticule extraction (SMILE) and femtosecond laser in situ keratomileusis (FS-LASIK).
abstract: OBJECTIVE
  To evaluate corneal reinnervation, and the corresponding corneal sensitivity and keratocyte density after small incision lenticule extraction (SMILE) and femtosecond laser in situ keratomileusis (FS-LASIK).
  
  
  METHODS
  In this prospective, non-randomized observational study, 18 patients (32 eyes) received SMILE surgery, and 22 patients (42 eyes) received FS-LASIK surgery to correct myopia. The corneal subbasal nerve density and microscopic morphological changes in corneal architecture were evaluated by confocal microscopy prior to surgery and at 1 week, 1 month, 3 months, and 6 months after surgery. A correlation analysis was performed between subbasal corneal nerve density and the corresponding keratocyte density and corneal sensitivity.
  
  
  RESULTS
  The decrease in subbasal nerve density was less severe in SMILE-treated eyes than in FS-LASIK-treated eyes at 1 week (P = 0.0147), 1 month (P = 0.0243), and 3 months (P = 0.0498), but no difference was detected at the 6-month visit (P = 0.5277). The subbasal nerve density correlated positively with central corneal sensitivity in both groups (r = 0.416, P<0.0001, and r = 0.2567, P = 0.0038 for SMILE group and FS-LASIK group, respectively). The SMILE-treated eyes have a lower risk of developing peripheral empty space with epithelial cells filling in (P = 0.0005).
  
  
  CONCLUSIONS
  The decrease in subbasal nerve fiber density was less severe in the SMILE group than the FS-LASIK group in the first 3 months following the surgeries. The subbasal nerve density was correlated with central corneal sensitivity.
authors.affiliation: Key Lab of Myopia, Ministry of Health, Department of Ophthalmology, EYE & ENT Hospital of Fudan University, Shanghai, China.
authors.forename: Meiyan
authors.initials: M
authors.lastname: Li
authors.affiliation: Key Lab of Myopia, Ministry of Health, Department of Ophthalmology, EYE & ENT Hospital of Fudan University, Shanghai, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Niu
authors.affiliation: Key Lab of Myopia, Ministry of Health, Department of Ophthalmology, EYE & ENT Hospital of Fudan University, Shanghai, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Qin
authors.affiliation: Department of Ophthalmology, Bronx Lebanon Hospital Center, Albert Einstein College of Medicine, Bronx, New York, United States of America.
authors.forename: Zimei
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Duke University, Durham, North Carolina, United States of America.
authors.forename: Katherine
authors.initials: K
authors.lastname: Ni
authors.affiliation: Key Lab of Myopia, Ministry of Health, Department of Ophthalmology, EYE & ENT Hospital of Fudan University, Shanghai, China.
authors.forename: Qihua
authors.initials: Q
authors.lastname: Le
authors.affiliation: Key Lab of Myopia, Ministry of Health, Department of Ophthalmology, EYE & ENT Hospital of Fudan University, Shanghai, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xiang
authors.affiliation: Key Lab of Myopia, Ministry of Health, Department of Ophthalmology, EYE & ENT Hospital of Fudan University, Shanghai, China.
authors.forename: Anji
authors.initials: A
authors.lastname: Wei
authors.affiliation: Department of Biostatistics, School of Public Health, Fudan University, Shanghai, China.
authors.forename: Weiping
authors.initials: W
authors.lastname: Ma
authors.affiliation: Key Lab of Myopia, Ministry of Health, Department of Ophthalmology, EYE & ENT Hospital of Fudan University, Shanghai, China.
authors.forename: Xingtao
authors.initials: X
authors.lastname: Zhou
mesh_terms: D000328:Adult; D003315:Cornea / Q000601:surgery*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D008297:Male; D018613:Microscopy, Confocal; D009412:Nerve Fibers; D011446:Prospective Studies; D055815:Young Adult