Abstract:  Objective To compare the central corneal thickness (CCT)  measurements obstained by Pentacam HR, specular microscopy (SP-3000P), swept-source optical coherence biometry(OA-2000) and optical coherence tomograhpy (Optovue Angiovue OCT with anterior segment lens). Design Diagnostic technique evaluation. Participants 118 eyes of 118 patients with healthy cornea at cataract clinic of Beijing Tongren Hospital from September to Novermber 2021. Method CCT values were obtained by these four instruments. The differences among CCT values of cornea apex from these four instruments, and the agreement between each two were evaluated. CCT values of cornea apex and pupil center from Pentacam HR, and CCT of cornea apex and average CCT of central 2 mm zone from Optovue OCT were also compared. Main Outcome Measures CCT, intraclass correlation coefficient (ICC), the mean difference and 95% limits of agreement (LoA) of Bland-Altman diagram. Results CCT of cornea apex obtained by Pentacam HR, SP-3000P, OA-2000 and Optovue OCT was 532.29±30.35 μm, 512.20±30.88 μm, 516.89±31.25 μm and 515.58±29.78 μm respectively. CCT of pupil center obtained by Pentacam HR was 531.25±30.75 μm, and average CCT of central 2 mm zone with Optovue OCT was 516.75±29.72 μm. Significant difference was found between CCT of cornea apex and CCT of pupil center from Pentacam HR (t=6.275, P＜0.001), and also between CCT of cornea apex and average CCT of central 2 mm zone from Optovue OCT (t=4.364, P＜0.001). There was significant difference among CCT of cornea apex obtained by these four optical instruments (F=559.469, P＜0.001) and between each two values with further pairwise comparison (OA 2000-Optovue OCT: P=0.022; other each two values: all P<0.001). ICC between Pentacam HR and other devices was 0.806-0.878, and Bland-Altman diagram showed that the mean difference was 15.40~20.09 μm, with 95% LoA 5.9~32.4 μm. ICC between SP-3000P and OA-2000, and between SP-3000P and Optovue OCT was 0.973 and 0.974, while the mean difference was -4.69 μm and -3.38 μm, and 95% LoA -15.6~8.6 μm. ICC between OA-2000 and Optovue OCT was 0.986, with the mean difference of 1.31 μm and 95%LoA -8.3~10.9 μm. Conclusions  SP-3000P, OA-2000 and Optovue OCT showed very strong correlation and comparable agreement with narrow 95% LoA when measuring the CCT of cornea apex, so the values could be used interchangeable in clinical practice. Penctacam HR overestimates other instruments with poor agreement, and the measurements are not interchangeable directly. (Ophthalmol CHN, 2022, 31: 440-445)

Key words: central corneal thickness, Pentacam HR, specular microscopy, swept-source optical coherence biometry, optical coherence tomography