Repeatability and reproducibility of corneal thickness using SOCT Copernicus HR

Abstract

Purpose: The aim of this study is to determine the reliability of corneal thickness measurements derived from SOCT Copernicus HR (Fourier domain OCT). Methods: Thirty healthy eyes of 30 subjects were evaluated. One eye of each patient was chosen randomly. Images were obtained of the central (up to 2.0 mm from the corneal apex) and paracentral (2.0 to 4.0 mm) cornea. We assessed corneal thickness (central and paracentral) and epithelium thickness. The intra-observer repeatability data were analysed using the intra-class correlation coefficient (ICC) for a range of 95 per cent within-subject standard deviation (SW) and the within-subject coefficient of variation (CW). The level of agreement by Bland-Altman analysis was also represented for the study of the reproducibility between observers and agreement between methods of measurement (automatic versus manual). Results: The mean value of the central corneal thickness (CCT) was 542.4 Ϯ 30.1 mm (SD). There was a high intra-observer agreement, finding the best result in the central sector with an intra-class correlation coefficient of 0.99, 95 per cent CI (0.989 to 0.997) and the worst, in the minimum corneal thickness, with an intra-class correlation coefficient of 0.672, 95 per cent CI (0.417 to 0.829). Reproducibility between observers was very high. The best result was found in the central sector thickness obtained both manually and automatically with an intra-class correlation coefficient of 0.990 in both cases and the worst result in the maximum corneal thickness with an intra-class correlation coefficient of 0.827. The agreement between measurement methods was also very high with intra-class correlation coefficient greater than 0.91. On the other hand the repeatability and reproducibility for epithelial measurements was poor. Conclusion: Pachymetric mapping with SOCT Copernicus HR was found to be highly repeatable and reproducible. We found that the device lacks an appropriate ergonomic design as proper focusing of the laser beam onto the cornea for anterior segment scanning required that patients were positioned slightly farther away from the machine head-rest than in the setup for retinal imaging.

Reliability of Entire Corneal Thickness Mapping in Normal Post-Laser in situ Keratomileusis and Keratoconus Eyes Using Long Scan Depth Spectral Domain Optical Coherence Tomography

“…Several reports have showed repeatability and reproducibility results of various OCT systems for corneal pachymetry, which are summarized in Table 3 [4,22,24,40,41,[49][50][51][52]. Our results showed a CoR of less than 3.54 μm for normal subjects and 3.78 μm for post-LASIK patients within the central zone (0-2 mm) and the paracentral zone (2-5 mm) for corneal thickness repeatability and reproducibility.…”

Repeatability of Corneal Epithelial Thickness Measurements Using Fourier-Domain Optical Coherence Tomography in Normal and Post-LASIK Eyes

“…There were a few studies in the literature that evaluated the reproducibility of central corneal ET measurements. 8-9, 12-13 In this study, we evaluated the repeatability of corneal ET and CT measurements at the center, paracentral and peripheral zones in normal and LASIK eyes using the RTVue.…”

“…Using the Fourier domain based device SOCT Copernicus HR, in 30 healthy eyes, Vidal et al 8 found that repeatability for corneal epithelial measurements was poor with ICC value of 0.391. In contrast, the ICC values for central corneal ET found in current study using the RTVue were >0.98.…”

“…It has been shown that the Fourier domain-based anterior segment OCT has a better reliability than time-domain OCT. 7 In normal subjects, Vidal et al 8 reported that the repeatability and reproducibility of corneal ET measurements was poor using the Fourier-domain SOCT Copernicus HR system, and Prakash and colleagues 9 found reliable and reproducible measurements of corneal ET at vertex using the Fourier-domain based Cirrus HD-OCT. The purpose of our study was to evaluate in normal and post-LASIK corneas the repeatability of corneal ET measurements made by the Fourier-domain based RTVue system (Optovue, Inc., Fremont, CA).…”

Reproducibility and Daytime-Dependent Changes of Corneal Epithelial Thickness and Whole Corneal Thickness Measured With Fourier Domain Optical Coherence Tomography

“…8 The intraobserver reproducibility of FD-OCT (SOCT Copernicus HR, Optopol, Poland) was substantial to almost perfect for automatically measured CT but only fair (ICC = 0.391) for manually assessed ET. 9 FD-OCT (Cirrus HD-OCT, Zeiss, Germany) presented an excellent intraobserver and interobserver reproducibility of ET and CT measured at the vertex. 10 In a retrospective study, Ma et al 5 reported an excellent intraobserver repeatability for ET and CT measured with the RTVue in 17 corneal zones in healthy and post-LASIK eyes.…”