Comparison of central corneal thickness measurements using optical low-coherence reflectometry, Fourier domain optical coherence tomography, and Scheimpflug camera

Abstract

Purpose: To compare the results of central corneal thickness (CCT) measurements obtained using optical low-coherence reflectometry (OLCR), Fourier domain optical coherence tomography (FD-OCT), and a Scheimpflug camera (SC), combined with Placido corneal topography. Methods: A total of 25 healthy subjects were enrolled in the present study, and one eye of each subject was included. A detailed ophthalmic examination was performed in all cases following CCT measurements with OLCR, FD-OCT, and SC. The results were compared using an ANOVA test. Bland-Altman analysis was used to demonstrate agreement between methods. Intra-examiner repeatability was assessed by using intraclass correlation coefficients (ICCs). Results: Statistically significant differences were observed between the results of the CCT measurements obtained using the three different devices (p=0.009). Significant correlations were found between OLCR and FD-OCT (r=0.97; p<0.0001), FD-OCT and SC (r=0.91; p<0.0001), and OLCR and SC (r=0.95; p<0.0001). The 95% limits of agreement (LOA) obtained from Bland-Altman plots were from -7.2 μm to 28.7 μm for OLCR versus FD-OCT, from -19.2 μm to 30.4 μm for OLCR versus SC, and from -42.6 to 32.3 μm for FD-OCT versus SC. Intra-examiner repeatability was excellent for each method, with ICCs >0.98. Conclusions: Although the results of CCT measurements obtained from these three devices were highly correlated with one another and the mean differences between instruments were comparable with the reported diurnal CCT fluctuation, the measurements are not directly interchangeable in clinical practice because of the wide LOA values.

Reproducibility of corneal, macular and retinal nerve fiber layer thickness measurements using the iVue-100 optical coherence tomography

“…Visante, 3D CAS-OCT, Slit-lamp OCT, RTVue-100) have shown ICC values ranging from 0.767–0.999, and COVs of less than 3.7%. 14 , 15 For example, Ishibazawa et al 15 reported that the RTVue had the best reproducibility with a mean ICC for corneal thickness of 0.980 and a mean COV of 3.64%. This could be due to the fact that the RTVue OCT obtains a high resolution of the cornea with similar shorter operating wave length of 840 nm compared to other devices, such as the Visante, which have longer operating wavelengths.…”

Reproducibility of Central Corneal Thickness Measurements in Normal Eyes Using the Zeiss Cirrus 5000 HD-OCT and Pentacam HR

“…Statistically significant differences were found between CCT Pent and both the CCT Pach , and CCT HDC , although the difference between CCT Pent and CCT AC was not statistically insignificant. Although previous studies have compared OCT and Scheimpflug-derived CCT measurements [ 21 , 26 , 27 , 32 - 35 ], to our knowledge, ours is the first to assess measurements obtained using the new external lenses for the Cirrus OCT.…”

“…Similarly, Gonul et al . compared CCT measurements taken with the RTVue-100 (Optovue Inc., Fremont, CA, USA) and Schiempflug camera Sirius (CSO Inc., Firenze, Italy) [ 32 ]. Although the mean CCT differences between instruments were not statistically significant and CCT measurements were correlated, the measurements were not considered to be interchangeable in clinical practice because of the wide LoA values.…”

Reproducibility and repeatability of central corneal thickness measurement in healthy eyes using four different optical devices

“…In this method, however, there are some limitations, such as direct contact of the equipment with the cornea, measurement of the estimated central point, limited definition of the thinnest point of the cornea, and variation according to the individual performing the measurement. Currently, devices such as optical, low-coherence reflectometry, optical coherence tomography, noncontact specular microscopy, and corneal topography have been developed to measure CCT with a noncontact optic method [3]. These noncontact methods are less dependent on the operator and have the advantage of demonstrating the thinnest parts of the cornea.…”