Agreement and repeatability of central corneal thickness measurements by four different optical devices and an ultrasound pachymeter

• Published in: International ophthalmology Vol. 39; no. 7; pp. 1589 - 1598
• Main Authors: Gokcinar, Nesrin Buyuktortop, Yumusak, Erhan, Ornek, Nurgul, Yorubulut, Serap, Onaran, Zafer
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-07-2019; Springer Nature B.V
• Subjects: Agreements; Computed tomography; Cornea; Correlation analysis; Correlation coefficients; Devices; Interferometry; Measurement methods; Measurement techniques; Medicine; Medicine & Public Health; Microscopy; Ophthalmology; Optical Coherence Tomography; Original Paper; Reproducibility; Thickness measurement; Ultrasonic imaging; Ultrasonic testing; Ultrasound; Central corneal thickness; Optical coherence tomography; Specular microscopy; Ultrasonic pachymeter; Optic biometry; Corneal topography
• ISSN: 0165-5701; 1573-2630
• DOI: 10.1007/s10792-018-0983-2

Purpose
To compare the repeatability and agreement of central corneal thickness (CCT) measurements by spectral-domain optical coherence tomography (OCT), corneal topography (CT) with a combined Scheimpflug–Placido system, optical biometry (OB), specular microscopy (SM), and ultrasound pachymetry (UP).
Methods
A single observer measured CCT twice in 150 eyes of 150 subjects with each of five devices: Nidek RS-3000 Advance OCT, CSO Sirius combined Scheimpflug–Placido disc system CT, Nidek AL-Scan partial coherence interferometry-based OB, Tomey EM-3000 SM, and Reichert iPac ultrasonic pachymeter. Pachymetry values corrected by the SM device software were also recorded. Levels of agreement between devices were evaluated by Bland–Altman plots with 95% limits of agreement, and repeatability for each device was analysed with intraclass correlation coefficients.
Results
The mean CCTs measured by OCT, CT, OB, SM, corrected SM, and UP were 544.60 ± 29.56, 536.19 ± 32.14, 528.29 ± 29.45, 524.88 ± 32.38, 537.88 ± 32.38, and 545.29 ± 30.75 μm, respectively. Mean CCT differed significantly between the devices (
p
 < 0.05) apart from between OCT and UP, and between CT and corrected SM. Mean paired differences between devices ranged between 0.68 and 20.41 μm. Repeatability with all devices was excellent (> 0.99). The range of limits of agreement was the least between OCT and UP.
Conclusions
Different CCT measurement techniques produce quite different results, so CCT evaluation and follow-up should be performed using the same device or devices with close compatibility.