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Comparison of reliability and repeatability of corneal curvature assessment with six keratometers

Hamer, Catriona A, Buckhurst, Hetal, Purslow, Christine, Shum, Gary L., Habib, Nabil E and Buckhurst, Phillip J (2016) Comparison of reliability and repeatability of corneal curvature assessment with six keratometers. Clinical and Experimental Optometry, 99 (6). pp. 583-589. ISSN 08164622

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Official URL: http://doi.org/10.1111/cxo.12329

Abstract

Background Keratometric methodology varies between instruments and the differences may have a clinical impact. We investigated the agreement and reproducibility of six keratometers. Methods Keratometry was performed on 100 subjects at two separate sessions with IOLMaster 500, Pentacam, OPD scanner, Medmont E300, Javal-Schiøtz and TMS-5. A second observer assessed 30 subjects to determine inter-observer variability. A single individual was assessed on 10 separate sessions to determine intra-observer variability. Data were analysed using coefficient of variation (CV) and intra-class correlation coefficient (ICCC) for intra-observer variation. Inter-observer concordance was evaluated by the ICCC. Bland–Altman plots, Pearson's correlation coefficient and repeated measures analysis of variance were used to assess agreement of data produced by the instruments. Results OPD scanner and Javal-Schiøtz mean spherical equivalent (MSE) results were systematically different (p < 0.001) from other instruments (flatter and steeper, respectively). J0/J45 were similar for all instruments (p < 0.05). Bland–Altman comparison plots indicated that Pentacam and IOLMaster demonstrated greatest level of agreement (ICC results MSE = 0.992, J0 = 0.934 and J45 = 0.890). Agreement (ICC) between observers for MSE ranged from 0.955 to 0.995 for all instruments; lower levels of agreement were found for J0/J45 (0.289 to 0.901). IOLMaster showed greatest correlation and Medmont the lowest. All instruments showed high intra-observer repeatability of MSE (CV 0.1 to 0.3 per cent). The J0/J45 readings showed greater variability (CV range 8.8 to 57.6 per cent). Conclusion When considering MSE alone IOLMaster, Pentacam, OPD scan and Medmont may be considered interchangeable; however, assessment of astigmatism shows greater variability between instruments, sessions and observers.

Item Type: Article
Additional Information: This is the peer reviewed version of the following article: Hamer, C., Buckhurst, H., Purslow, C., Shum, G., Habib, N. and Buckhurst, P. (2016) Comparison of reliability and repeatability of corneal curvature assessment with six keratometers. Clinical and Experimental Optometry. Vol. 99, No. 6: 583-589 which has been published in final form at http://doi.org/10.1111/cxo.12329 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
Divisions: ?? UniversityCollegePlymouthMarkJohn ??
Depositing User: Mrs Wendy Evans
Date Deposited: 01 Feb 2017 10:15
Last Modified: 22 May 2019 11:50
URI: http://marjon.collections.crest.ac.uk/id/eprint/14615

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