title: Dry eye after LASIK with a femtosecond laser or a mechanical microkeratome.
abstract: OBJECTIVE
  Dry eye is the most common complication after LASIK procedure and is associated with corneal denervation. We conducted the study to compare dry eye parameters and corneal sensitivity (CS) after laser in situ keratomileusis (LASIK) with a femtosecond laser (FS) or microkeratome (MK).
  
  
  METHODS
  In this prospective, nonrandomized, comparative study, 87 consecutive patients with myopia were assigned to receive either LASIK surgery with an FS (n = 44) or MK-assisted LASIK surgery (n = 43). The groups were age and sex matched. Corneal sensitivity, Schirmer testing, tear breakup time (TBUT), conjunctival and corneal stainings, and a subjective questionnaire (Ocular Surface Disease Index [OSDI]) were evaluated preoperatively, at 1 week, and at 1, 3, and 6 months postoperatively.
  
  
  RESULTS
  Preoperative spherical equivalent and sphere, calculated ablation depth, and suction time differed significantly between the two groups (p < 0.01, all comparisons). Postoperatively, CS decreased in both groups and gradually recovered. Schirmer test values were not significantly different throughout the postoperative time points between the groups. Laser in situ keratomileusis-induced corneal epitheliopathy was also increased after operation in both groups. However, there was no significant difference between the groups in corneal and conjunctival staining scores. The OSDI scores were increased postoperatively in both groups. After adjustment for the calculated ablation depth, TBUT was the only parameter that was statistically higher in the FS group than in the MK group (p = 0.03).
  
  
  CONCLUSIONS
  Both FS- and MK-assisted LASIK reduced CS and TBUT and increased corneal staining and OSDI scores. However, TBUT was significantly higher in the FS group than in the MK group after operation.
authors.affiliation: *MD, PhD †BS ‡MD §PhD Department of Ophthalmology, Chang Gung Memorial Hospital, Keelung, Taiwan (C-CS, Y-FL); Department of Chinese Medicine, Chang Gung University, Kwei-shan, Taoyuan, Taiwan (C-CS, DH-KM); Nobel Laser Eye Center, Taipei, Taiwan (C-KC); Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan (DH-KM, K-JC, M-HS, C-HH); and Department of Beauty Science, Meiho Institute of Technology, Pingtung, Taiwan (P-HW).
authors.forename: Chi-Chin
authors.initials: CC
authors.lastname: Sun
authors.forename: Chao-Kai
authors.initials: CK
authors.lastname: Chang
authors.forename: David Hui-Kang
authors.initials: DH
authors.lastname: Ma
authors.forename: Yi-Fang
authors.initials: YF
authors.lastname: Lin
authors.forename: Kuan-Jen
authors.initials: KJ
authors.lastname: Chen
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Sun
authors.forename: Ching-Hsi
authors.initials: CH
authors.lastname: Hsiao
authors.forename: Pei-Hsuan
authors.initials: PH
authors.lastname: Wu
mesh_terms: D000328:Adult; D003315:Cornea / Q000503:physiopathology*; D015352:Dry Eye Syndromes / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000295:instrumentation / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D009216:Myopia / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications; D011446:Prospective Studies; D012677:Sensation / Q000502:physiology; D013524:Surgical Flaps; D011795:Surveys and Questionnaires; D013666:Tears / Q000737:chemistry