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Int Ophthalmol (2014) 34:869875 DOI 10.1007/s10792-013-9895-3
ORIGINAL PAPER
Keratometry with ve different techniques: a study of device repeatability and inter-device agreement
Shiva Mehravaran Soheila Asgari
Sara Bigdeli Ashkan Shahnazi Hassan Hashemi
Received: 9 September 2013 / Accepted: 30 December 2013 / Published online: 23 February 2014 Springer Science+Business Media Dordrecht 2014
Abstract The purpose of this study was to determine and compare the repeatability of keratometry measurements with the Javal manual keratometer, Topcon automated kerato-refractometer, IOLMaster, EyeSys Corneal Analysis System, and Pentacam Scheimpug Topography System, and determine the agreement of measurements of the latter four devices with the Javal keratometer as the gold standard. In this cross-sectional study, 21 people with no history of ocular disease or surgery were examined twice with each device. Minimum, maximum, and average keratometry readings were recorded in diopters (D) for each eye and used in the analyses. For statistical analysis, we determined correlation coefcients and used the BlandAltman method and calculated the 95 % limits of agreement (LoA). All repeatability coefcients were satisfactorily high. Best repeatability for minimum keratometry and maximum keratometry readings was seen with IOLMaster (95 % LoA -0.23 to0.19 D and -0.31 to 0.32 D, respectively). Agreement with Javal manual keratometry was best with Topcon and IOLMaster for minimum keratometry readings (95 % LoA -0.67 to 0.28 D and -0.57 to 0.38 D,
respectively), and with Topcon for maximum keratometry readings (95 % LoA -0.85 to 0.63 D). In our series of normal eyes, keratometry readings with Topcon, IOLMaster, and Pentacam showed very good agreement with Javal measurements, and inter-device agreements were better than the repeatability of the manual gold standard. However, differences between Javal and EyeSys may not be clinically acceptable, and these two devices should not be used interchangeably. Further studies are needed to investigate these issues in non-virgin eyes.
Keywords Keratometry Javal manual
keratometer Topcon automated kerato
refractometer IOLMaster EyeSys Corneal
Analysis System Pentacam Scheimpug
Topography System
Introduction
Keratometry, the measurement of the anterior corneal curvature, can now be performed with a variety of devices. Accurate measurements are needed in various elds of research and clinical practice where keratometry values can reveal cases of corneal disease such as keratoconus and help determine eligibility for refractive surgery [1, 2]. Keratometry is also an essential...