title: [Femtosecond lenticule extraction for correction of myopia: clinical results and recovery of subbasal nerves].
abstract: OBJECTIVE
  To investigate the clinical efficacy, safety, predictability, corneal sensitivity, tear function and recovery of subbasal nerves after femtosecond lenticule extraction (FLEx) and laser in situ keratomileusis (LASIK).
  
  
  METHODS
  In this prospective, nonrandomized, comparative clinical study, 49 patients (98 eyes) were divided into two groups. FLEx was performed to treat myopia by Visumax femtosecond laser system, and LASIK was performed by Allegretto Wave laser system. The patients were followed up for 6 months. Visual acuity, manifest refraction, intraocular pressure, slit-lamp examination, corneal topography by Pentacam, tear break-up time, Schirmer test, corneal sensitivity and confocal microscopy were assessed.
  
  
  RESULTS
  Forty-four patients (88 eyes) completed the 6-month follow-up. Best corrected visual acuity (BCVA) was 0.89±0.14 in eyes with FLEx and 0.98±0.08 in eyes with LASIK at 1 day after surgery. After 10 days, BCVA was 0.98±0.09 and 1.02±0.09, respectively. At the final follow-up visit, the efficacy index was 1.09 in the FLEx group and 1.07 in the LASIK group, and the safety index was 1.12 and 1.07, respectively, in the two groups. Mean Schirmer score was (16.92±7.58) mm and (15.03±5.89) mm (t=1.316, P=0.192), mean tear break-up time was (8.94±2.57) s and (8.00±2.39) s (t=1.759, P=0.082), and corneal sensitivity was (56.46±4.49) mm and (51.38±8.16) mm (t=1.316, P=0.001) in the groups of FLEx and LASIK, respectively. At 10 days after surgery, the number of subbasal nerves was significantly decreased in the FLEx group, and in the LASIK group the subbasal nerve fibers were hardly observed. At 6 months, regenerated nerve fibers were evident in the subbasal area, which recovered faster in eyes with FLEx than in those with LASIK.
  
  
  CONCLUSIONS
  Femtosecond lenticule extraction appears to be efficient, safe and predictable for myopia. FLEx surgery is superior over LASIK in less reduction of corneal sensation and lower risk of harm to the subbasal nerve fibers.
authors.affiliation: Eye Institute, Affiliated Hospital of Nantong University, Nantong 226001, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Yu
authors.forename: X L
authors.initials: XL
authors.lastname: Cheng
authors.forename: L Q
authors.initials: LQ
authors.lastname: Gu
authors.forename: G J
authors.initials: GJ
authors.lastname: Jing
authors.forename: H
authors.initials: H
authors.lastname: Chen
mesh_terms: D003315:Cornea / Q000601:surgery*; D019781:Corneal Topography; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D053685:Laser Therapy / Q000379:methods*; D054018:Lasers, Excimer; D018613:Microscopy, Confocal; D009216:Myopia / Q000601:surgery*; D009412:Nerve Fibers; D011446:Prospective Studies; D013666:Tears; D014065:Tonometry, Ocular; D016896:Treatment Outcome; D014792:Visual Acuity