Comparison of corneal tomography using a novel swept-source optical coherence tomographer and rotating Scheimpflug system in normal and keratoconus eyes: repeatability and agreement analysis

Table 3 Repeatability of posterior corneal curvature parameters of all used devices

Parameter	Device	Normal eyes				Mild KC				Moderate KC
Parameter	Device	Mean ± SD	Sw	Repeatability	CV (%)	Mean ± SD	Sw	Repeatability	CV (%)	Mean ± SD	Sw	Repeatability	CV (%)
Flat SimK (D)	RSC	− 5.9 ± 0.3	0.035	0.098	− 0.362	− 6.2 ± 0.4	0.105	0.291	− 0.976	− 7.2 ± 0.9	0.091	0.251	− 0.926
Flat SimK (D)	SS-OCT	− 5.9 ± 0.2	0.005	0.015	− 0.078	− 6.1 ± 0.4	0.017	0.048	− 0.236	− 7.3 ± 1.0	0.041	0.114	− 0.408
Steep SimK (D)	RSC	− 6.3 ± 0.2	0.028	0.077	− 0.211	− 6.8 ± 0.4	0.068	0.188	− 0.722	− 8.0 ± 1.0	0.074	0.206	− 0.734
Steep SimK (D)	SS-OCT	− 6.2 ± 0.2	0.008	0.021	− 0.100	− 6.9 ± 0.5	0.020	0.055	− 0.258	− 8.1 ± 1.0	0.033	0.092	− 0.312
Average SimK (D)	RSC	− 6.1 ± 0.2	0.028	0.077	− 0.220	− 6.5 ± 0.4	0.065	0.180	− 0.726	− 7.6 ± 0.9	0.064	0.177	− 0.681
Average SimK (D)	SS-OCT	− 6.0 ± 0.2	0.005	0.015	− 0.073	− 6.5 ± 0.4	0.014	0.039	− 0.190	− 7.7 ± 1.0	0.033	0.092	− 0.340
Astigmatism (D)	RSC	− 0.4 ± 0.2	0.036	0.101	− 7.107	− 0.6 ± 0.3	0.120	0.333	− 23.142	− 0.8 ± 0.5	0.099	0.276	− 14.586
Astigmatism (D)	SS-OCT	− 0.4 ± 0.2	0.009	0.025	− 2.720	− 0.8 ± 0.4	0.022	0.062	− 2.281	− 0.8 ± 0.4	0.039	0.107	− 4.616
Kmax (D)	RSC	− 6.5 ± 0.3	0.034	0.095	− 0.460	− 8.2 ± 0.7	0.160	0.443	− 1.570	− 9.9 ± 1.5	0.176	0.488	− 1.459
Kmax (D)	SS-OCT	− 6.3 ± 0.3	0.014	0.039	− 0.188	− 8.1 ± 0.8	0.045	0.124	− 0.407	− 9.8 ± 1.5	0.071	0.196	− 0.519
BFS (mm)	RSC	6.6 ± 0.2	0.013	0.036	0.150	6.4 ± 0.2	0.016	0.045	0.213	6.1 ± 0.4	0.020	0.055	0.237
BFS (mm)	SS-OCT	6.7 ± 0.2	0.010	0.029	0.100	6.5 ± 0.2	0.008	0.023	0.099	6.1 ± 0.4	0.010	0.028	0.161

BFS = best-fit sphere; CV = coefficient of variation; Kmax = maximum keratometry; KC = keratoconus; repeatability = coefficient of repeatability; RSC = rotating Scheimpflug camera; SimK = simulated keratometry value; SS-OCT = swept-source optical coherence tomography; Sw = within-subject standard deviation

ISSN: 2326-0254