title: Reliability of Pentacam HR Thickness Maps of the Entire Cornea in Normal, Post-Laser In Situ Keratomileusis, and Keratoconus Eyes.
abstract: OBJECTIVE
  To measure the repeatability and reproducibility of Pentacam HR system thickness maps for the entire cornea in normal, post-laser in situ keratomileusis (post-LASIK), and keratoconus (KC) eyes.
  
  
  METHODS
  Reliability study.
  
  
  METHODS
  Sixty normal subjects (60 eyes), 30 post-LASIK subjects (60 eyes), and 14 KC patients (27 eyes) were imaged with the Pentacam HR system by 2 well-trained operators. For pachymetry the cornea was divided into 4 zones: a central zone (2-mm diameter) and concentric pericentral zone (2-5 mm), transitional zone (5-7 mm), and peripheral zone (7-10 mm). The 3 concentric zones were subdivided into 8 sectors. Intraobserver repeatability and interobserver reproducibility of entire corneal thickness maps were tested by the repeatability and reproducibility coefficients, intraclass correlation coefficients, coefficient of variation, and 95% limits of agreement.
  
  
  RESULTS
  From central to peripheral zones, the precision of corneal thickness measurements became gradually smaller. Central zone repeatability and reproducibility were the best in the normal, post-LASIK, and KC groups. The peripheral superior sectors showed poorer repeatability and reproducibility for all subjects. The intraobserver repeatability and interobserver reproducibility for all zones were ≤19.3 μm, ≤22.1 μm, and ≤20.7 μm, in the normal, post-LASIK, and KC groups, respectively. The intraobserver and interobserver coefficients of variation for all zones were ≤1.3%, ≤1.6%, and ≤1.6% for all 3 groups.
  
  
  CONCLUSIONS
  Pentacam HR system pachymetry of the entire cornea provided good precision in normal, post-LASIK, and KC corneas. Thickness measurements in the peripheral cornea should be interpreted with caution in abnormal corneas after surgery or with diseases.
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Xu
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Peng
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Jiang
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Yang
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.
authors.forename: Weigen
authors.initials: W
authors.lastname: Zhu
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Lu
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China. Electronic address: shenmxiao7@hotmail.com.
authors.forename: Meixiao
authors.initials: M
authors.lastname: Shen
mesh_terms: D000328:Adult; D003315:Cornea / Q000033:anatomy & histology* / Q000473:pathology*; D063171:Corneal Pachymetry / Q000592:standards*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007640:Keratoconus / Q000473:pathology*; D020731:Keratomileusis, Laser In Situ; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult