title: Flap thickness variation with 3 types of microkeratome heads.
abstract: OBJECTIVE
  To determine flap thickness variation with 3 types of microkeratome heads and identify the potential factors that affect flap thickness.
  
  
  METHODS
  Ruijin Hospital, Department of Ophthalmology, Shanghai, China.
  
  
  METHODS
  Comparative case series.
  
  
  METHODS
  Laser in situ keratomileusis was performed using the Moria microkeratome with the One Use-Plus SBK, M2 90, or M2 110 head. Flap thickness was calculated by subtraction pachymetry. Age, central corneal thickness (CCT), spherical equivalent refraction, mean keratometry, and horizontal corneal diameter were recorded preoperatively.
  
  
  RESULTS
  The study comprised 180 eyes of 90 patients; 60 eyes were treated with each head. The difference in mean flap thickness between right and left eyes was not significant in the SBK group (97.50 μm ± 11.39 [SD] versus 96.73 ± 10.45 μm; P = .44) but was significant in the M2 90 group (128.03 ± 12.03 μm versus 123.40 ± 12.38 μm; P = .0071) and the M2 110 group (140.53 ± 15.14 μm versus 135.23 ± 18.03 μm, P = .0035). The difference from the intended flap thickness (right eyes and left eyes) was 2.50 ± 11.39 μm and 3.27 ± 10.45 μm, respectively, in the SBK group; -8.03 ± 12.03 μm and -3.40 ± 12.38 μm, respectively, in the M2 90 group; and -0.53 ± 15.14 μm and 4.77 ± 18.03 μm, respectively, in the M2 110 group. Flap thickness was positively correlated with baseline CCT in each group.
  
  
  CONCLUSIONS
  Flap thickness was positively correlated with the preoperative CCT using the Moria microkeratome. The SBK head demonstrated the most accurate flap thickness, followed by the M2 90 head and the 110 head.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: Department of Ophthalmology, Ruijin Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Du
authors.forename: Jingcai
authors.initials: J
authors.lastname: Lian
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Sheng
authors.initials: S
authors.lastname: Ye
authors.forename: Shiqi
authors.initials: S
authors.lastname: Dong
mesh_terms: D000293:Adolescent; D000328:Adult; D001837:Body Weights and Measures; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000295:instrumentation* / Q000592:standards; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D009216:Myopia / Q000601:surgery*; D009887:Ophthalmoscopy; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology; D015203:Reproducibility of Results; D013524:Surgical Flaps / Q000473:pathology*; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult