title: Precision and agreement of corneal power measurements obtained using a new corneal topographer OphthaTOP.
abstract: OBJECTIVE
  To evaluate repeatability and reproducibility of anterior corneal power measurements obtained with a new corneal topographer OphthaTOP (Hummel AG, Germany) and agreement with measurements by a rotating Scheimpflug camera (Pentacam HR, Oculus, Germany) and an automated keratometer (IOLMaster, Carl Zeiss Meditec, Germany).
  
  
  METHODS
  The right eyes of 79 healthy subjects were prospectively measured three times with all three devices. Another examiner performed three additional scans with the OphthaTOP in the same session. Within one week, the first examiner repeated the measurements using the OphthaTOP. The flat simulated keratometry (Kf), steep K (Ks), mean K (Km), J0, and J45 were noted. Repeatability and reproducibility of measurements were assessed by within-subject standard deviation (Sw), repeatability (2.77 Sw), coefficient of variation (CoV), and intraclass correlation coefficient (ICC). Agreement between devices was assessed using 95% limits of agreement (LoA).
  
  
  RESULTS
  Intraobserver repeatability and interobserver and intersession reproducibility of all measured parameters showed a 2.77 Sw of 0.29 diopter or less, a CoV of less than 0.24%, and an ICC of more than 0.906. Statistically significant differences (P<0.001) were found between the parameters analyzed by the three devices, except J0 and J45. The mean differences between OphthaTOP and the other two devices were small, and the 95% LoA was narrow for all results.
  
  
  CONCLUSIONS
  The OphthaTOP showed excellent intraobserver repeatability and interobserver and intersession reproducibility of corneal power measurements. Good agreements with the other two devices in these parameters were found in healthy eyes.
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Vision Science, Ministry of Health P.R. China, Wenzhou, Zhejiang, China.
authors.forename: Jinhai
authors.initials: J
authors.lastname: Huang
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; Studio Oculistico d'Azeglio, Bologna, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Savini
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Vision Science, Ministry of Health P.R. China, Wenzhou, Zhejiang, China.
authors.forename: Fangjun
authors.initials: F
authors.lastname: Bao
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Yuanguang
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Haisi
authors.initials: H
authors.lastname: Chen
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Weicong
authors.initials: W
authors.lastname: Lu
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Vision Science, Ministry of Health P.R. China, Wenzhou, Zhejiang, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Yu
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Vision Science, Ministry of Health P.R. China, Wenzhou, Zhejiang, China.
authors.forename: Qinmei
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003315:Cornea / Q000033:anatomy & histology*; D019781:Corneal Topography / Q000295:instrumentation* / Q000379:methods; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010781:Photography / Q000295:instrumentation* / Q000379:methods; D011446:Prospective Studies; D015203:Reproducibility of Results; D055815:Young Adult