title: Myopic Laser Corneal Refractive Surgery Reduces Interdevice Agreement in the Measurement of Anterior Corneal Curvature.
abstract: OBJECTIVE
  To investigate interdevice differences and agreement in the measurement of anterior corneal curvature obtained by different technologies after laser corneal refractive surgery.
  
  
  METHODS
  The prospective study comprised 109 eyes of 109 consecutive patients who had undergone laser-assisted in situ keratomileusis (LASIK). Preoperative and postoperative corneal parameters were measured by Scheimpflug imaging (Pentacam), Placido-slit-scanning (Orbscan) and auto-keratometry (IOLMaster). Preoperative and postoperative anterior corneal curvatures (K readings) were compared between devices. Interdevice agreement was evaluated by Bland-Altman analysis.
  
  
  RESULTS
  Preoperatively, the difference of K reading for Pentacam-IOLMaster (0.04±0.20 D) was not statistically significant (P=0.059). The differences between Pentacam-Orbscan and Orbscan-IOLMaster were 0.20±0.34 D (P<0.001) and -0.17±0.29 D (P<0.001), respectively. After surgery, no difference was found for Pentacam-Orbscan (-0.05±0.38, P=0.136). The differences between Pentacam-IOLMaster and Orbscan-IOLMaster were 0.13±0.29 D (P<0.001) and 0.19±0.34 D (P<0.001). Preoperative interdevice agreement (95% limit of agreement [LOA]) between Pentacam and Orbscan, Pentacam and IOLMaster, and Orbscan and IOLMaster were 1.31 D, 0.79 D and 1.14 D, respectively. The 95% LOAs decreased to 1.47 D, 1.14 D, and 1.34 D after refractive surgery.
  
  
  CONCLUSIONS
  Corneal refractive surgery changed the preoperative and postoperative interdevice differences in corneal curvature measurements and reduced interdevice agreement, indicating that the devices are not interchangeable.
authors.affiliation: Department of Ophthalmology (H.J., P.Z.), Xinhua Hospital Affiliated to Medical College of Shanghai Jiaotong University, Shanghai, China; Department of Physics (Z.O.), Shanghai University, Shanghai, China; and Department of Ophthalmology (H.G.), Aier Eye Hospital, Zhengzhou, China.
authors.forename: Haiying
authors.initials: H
authors.lastname: Jin
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Ou
authors.forename: Haike
authors.initials: H
authors.lastname: Guo
authors.forename: Peiquan
authors.initials: P
authors.lastname: Zhao
mesh_terms: D000293:Adolescent; D000328:Adult; D003315:Cornea / Q000000981:diagnostic imaging*; D019781:Corneal Topography / Q000379:methods*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D008297:Male; D009216:Myopia / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D011446:Prospective Studies; D012372:ROC Curve; D012029:Refraction, Ocular / Q000502:physiology*; D055815:Young Adult