Repeatability and reproducibility of subfoveal choroidal thickness in normal eyes of Japanese using different SD-OCT...

To compare subfoveal choroidal thickness (SCT) measurements of three different commercially available spectral-domain optical coherence tomography instruments with healthy eyes of Japanese.

A prospective, cross-sectional study was performed at a single institution. SCT of the right eye of 43 normal subjects was measured using three different SD-OCTs: Heidelberg Spectralis-OCT (Spectralis), Cirrus HD-OCT (Cirrus), and Topcon 3D OCT-1000 Mark II (Topcon). Two separate measurements were performed for the same eye with a maximum by a single examiner. SCT was defined as the distance from the posterior edge of the retinal pigment epithelium to the choroid/sclera junction. After manual segmentation, measurements were made using calipers equipped on each machine by masked raters. Intraclass, interrater, and intermachine agreements were assessed.

Forty-three subjects (mean age, 30.5 years) were enrolled. Of 43 eyes, the SCT of 39 eyes (90.7%) could be measured using each machine. Intraclass correlation coefficients (95% confidence intervals) were 0.976 (0.954-9.987), 0.958 (0.919-0.978), and 0.939 (0.895-0.971) with Spectralis, Cirrus, and Topcon, respectively. Interrater correlation coefficients (95% confident interval) were 0.944 (0.893 to 0.971), 0.956 (0.831 to 0.983), and 0.924 (0.825 to 0.964) with Spectralis, Cirrus, and Topcon, respectively. The average SCT was 272.6, 272.8, and 269.2 μm with Spectralis, Cirrus, and Topcon, respectively. The intermachine correlation coefficient was significantly high among the machines (P<0.001, Spearman), 0.97 (Spectralis-Cirrus), 0.96 (Cirrus-Topcon), and 0.98 (Topcon-Cirrus). Bland-Altman plot analysis showed no typical trend among the machines.

SCT measurements obtained with three different SD-OCTs were highly correlated and could be used interchangeably. (http://upload.umin.ac.jp number, UMIN000005287.).