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BioMed Research International
Volume 2013, Article ID 370592, 5 pages
Research Article

Repeatability and Reproducibility of Measurements Using a NT-530P Noncontact Tono/Pachymeter and Correlation of Central Corneal Thickness with Intraocular Pressure

1Department of Rehabilitation, Orthoptics and Visual Science Course, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Minamiku, Sagamihara, Kanagawa 252-0373, Japan
2Department of Ophthalmology, Kitasato University Hospital, 1-15-1 Kitasato, Minamiku, Sagamihara, Kanagawa 252-0373, Japan
3Department of Ophthalmology, School of Medicine, Kitasato University, 1-15-1 Kitasato, Minamiku, Sagamihara, Kanagawa 252-0373, Japan

Received 21 June 2013; Revised 30 August 2013; Accepted 3 September 2013

Academic Editor: Toshiaki Kubota

Copyright © 2013 Fusako Fujimura et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Purpose. To investigate the repeatability and reproducibility of intraocular pressure (IOP) and central corneal thickness (CCT) measurements using a noncontact tono/pachymeter (NT-530P) and to assess the correlation of CCT with IOP. Methods. Forty-six eyes of healthy volunteers were measured by two examiners. Three consecutive measurements per eye were performed. Repeatability was assessed using the coefficient of variation, and reproducibility was assessed using Bland-Altman plots. Linear correlations were used to determine agreement between CCT and noncorrected IOP and CCT and corrected IOP, which was calculated using a formula built into the NT-530P. Results. The coefficient of variation for IOP was 6.4% and for CCT was 0.4%. The 95% limits of agreement between examiners were  mmHg (range: to 2.61 mmHg) for IOP, μm (range: to 7.64 μm) for CCT. The corrected IOP was significantly higher than the noncorrected IOP (). The noncorrected IOP significantly correlated with CCT (, ). The corrected IOP showed no significant correlation with CCT (, ). Conclusions. NT-530P offered repeatability and reproducibility in both IOP and CCT measurements. The corrected IOP calculated using the NT-530P was independent of the CCT, suggesting that this IOP may be less influenced by the central corneal thickness.