Itrace ora7/27/2023 ![]() ![]() This study was conducted in the Department of Ophthalmology, Shanghai Jiaotong University Affiliated Sixth Hospital. Only the right eye of each subject was selected for all measurements. ![]() The mean age was 35.11 ± 12.88 years (range 21 to 69 years), and the mean spherical equivalent refraction was -3.00 ± 3.15 diopters (D range -9.00 to +1.00 D). In this prospective study, 100 normal and healthy subjects, including 43 males and 57 females were enrolled. The purpose of this study was to prospectively assess the intraobserver repeatability and interobserver and intersession reproducibility of corneal power measurements obtained by Topcon KR-1W and iTrace, and then to estimate the agreement of the results obtained by Topcon KR-1W and iTrace with those obtained by IOLMaster and Topolyzer. ![]() To the best of our knowledge, there have been no reported studies that determined the agreement of corneal power measurements between these 2 devices and other instruments, such as IOLMaster or Allegro Topolyzer, which are widely used in clinical practice. Several studies have reported the repeatability and reproducibility of aberrometry obtained by the 2 devices. In addition to ocular aberrometry, this device has an incorporated Placido-based topographic system that provides corneal topographic maps. The iTrace system (Tracey Technologies Corp., Houston, TX) uses the principle of ray tracing for obtaining the wavefront aberrations of the eye. The Topcon KR-1W system includes 3 different technologies for analysis of the human eye: wavefront aberrometry based on the Hartmann-Shack principle, Placido-disk corneal topography, and standard auto-refraction. For all the devices, the corneal power can be calculated by the anterior corneal curvature in certain central corneal surface, the standard corneal refractive index (1.3375) and the refractive index of air (1.000). There are several types of devices that can be used for corneal power measurement, such as manual or automated keratometry (e.g., IOLMaster), computerized videokeratography based on Placido-disk (e.g., Allegro Topolyzer), Slit-scan system (e.g., Orbscan), Scheimpflug rotating camera system (e.g., Pentacam) and optical coherence tomography (e.g., RTVue100 Fourier-domain OCT). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist.Īccurate corneal power measurement is essential for managing keratorefractive surgery, calculating intraocular lens (IOL) power, and fitting orthokeratology or customized contact lenses. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: All relevant data are within the paper and its Supporting Information files.įunding: Financial support provided by the Health Bureau of Shanghai City (201440029) to Q. Received: ApAccepted: DecemPublished: January 11, 2016Ĭopyright: © 2016 Hua et al. ![]() PLoS ONE 11(1):Įditor: Sanjoy Bhattacharya, Bascom Palmer Eye Institute, University of Miami School of Medicine, UNITED STATES Citation: Hua Y, Xu Z, Qiu W, Wu Q (2016) Precision (Repeatability and Reproducibility) and Agreement of Corneal Power Measurements Obtained by Topcon KR-1W and iTrace. ![]()
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