title: Intraobserver repeatability and interobserver reproducibility of corneal measurements in normal eyes using an optical coherence tomography-Placido disk device.
abstract: OBJECTIVE
  To study intraobserver and interobserver reproducibility of corneal topography and aberrometry measurements using a device combining optical coherence tomography (OCT) and a Placido disk (Visante Omni).
  
  
  METHODS
  Singapore National Eye Centre, Singapore.
  
  
  METHODS
  Prospective nonrandomized study.
  
  
  METHODS
  Measurements of simulated keratometry (K), anterior mean curvature, spherical anterior and posterior elevations, 4.5 mm diameter zone aberrometry (spherical aberration, asphericity, astigmatism), pachymetry, and white-to-white (WTW) diameter were taken in normal right eyes. Mean biases and limits of agreement (LoA) were obtained using Bland-Altman analysis.
  
  
  RESULTS
  Regarding intraobserver repeatability, the mean biases for simulated K, anterior mean curvature, spherical anterior/posterior elevation, 4.5 mm zone aberrometry, pachymetry, and WTW diameter were not statistically significant (P > .05). The LoA for the anterior mean curvature measurements were flat K, -3.96 diopters (D) and 4.86 D; steep K, -4.50 D and 4.27 D; mean K, -2.48 D and 2.09 D. The LoA for WTW were -9.90 mm and 8.74 mm. Regarding interobserver reproducibility, the mean biases for simulated K, anterior mean curvature, spherical anterior/posterior elevation, 4.5 mm zone aberrometry, pachymetry, and WTW diameter were not statistically significant (P > .05). The LoA for anterior mean curvature were flat K, -4.05 D and 4.13 D; steep K, -5.08 D and 3.85 D; mean K, -2.65 D and 2.29 D. The LoA for WTW diameter were -8.79 mm and 8.24 mm.
  
  
  CONCLUSIONS
  The OCT-Placido device had high intraobserver and interobserver clinical reproducibility for measurements of simulated K, 4.5 mm zone aberrometry, pachymetry, and standard anterior/posterior corneal elevation. However, intraobserver and interobserver reproducibility of anterior mean curvature measurements and WTW diameter was lower.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors: From the Department of Ophthalmology (Shah), Changi General Hospital, Singapore National Eye Centre (Han, Mehta), Singapore Eye Research Institute (Han, Htoon, Mehta), the Department of Ophthalmology (Mehta), Yong Loo Lin School of Medicine, National University of Singapore, and the Department of Clinical Sciences (Mehta), Duke-NUS Graduate Medical School, Singapore.
authors: Jinesh M
authors: JM
authors: Shah
authors: From the Department of Ophthalmology (Shah), Changi General Hospital, Singapore National Eye Centre (Han, Mehta), Singapore Eye Research Institute (Han, Htoon, Mehta), the Department of Ophthalmology (Mehta), Yong Loo Lin School of Medicine, National University of Singapore, and the Department of Clinical Sciences (Mehta), Duke-NUS Graduate Medical School, Singapore.
authors: Daphne
authors: D
authors: Han
authors: From the Department of Ophthalmology (Shah), Changi General Hospital, Singapore National Eye Centre (Han, Mehta), Singapore Eye Research Institute (Han, Htoon, Mehta), the Department of Ophthalmology (Mehta), Yong Loo Lin School of Medicine, National University of Singapore, and the Department of Clinical Sciences (Mehta), Duke-NUS Graduate Medical School, Singapore.
authors: Hla Myint
authors: HM
authors: Htoon
authors: From the Department of Ophthalmology (Shah), Changi General Hospital, Singapore National Eye Centre (Han, Mehta), Singapore Eye Research Institute (Han, Htoon, Mehta), the Department of Ophthalmology (Mehta), Yong Loo Lin School of Medicine, National University of Singapore, and the Department of Clinical Sciences (Mehta), Duke-NUS Graduate Medical School, Singapore. Electronic address: jodmehta@gmail.com.
authors: Jodhbir S
authors: JS
authors: Mehta
mesh_terms: D057128:Aberrometry / Q000295:instrumentation / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D003315:Cornea / Q000033:anatomy & histology*; D063171:Corneal Pachymetry; D019781:Corneal Topography / Q000295:instrumentation / Q000706:statistics & numerical data*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000295:instrumentation*; D055815:Young Adult