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 2 Repeatability of anterior 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	41.9 ± 1.1	0.071	0.196	0.129	43.2 ± 1.5	0.182	0.504	0.309	48.2 ± 4.8	0.283	0.784	0.414
Flat SimK (D)	SS-OCT	42.1 ± 1.1	0.095	0.263	0.184	43.4 ± 1.4	0.134	0.372	0.262	47.6 ± 4.6	0.173	0.480	0.305
Steep SimK (D)	RSC	43.2 ± 1.4	0.071	0.196	0.130	46.3 ± 2	0.187	0.519	0.271	52.0 ± 4.9	0.332	0.919	0.464
Steep SimK (D)	SS-OCT	43.4 ± 1.3	0.100	0.277	0.188	46.8 ± 2.0	0.145	0.402	0.271	51.9 ± 4.6	0.200	0.554	0.309
Average SimK (D)	RSC	42.5 ± 1.1	0.063	0.175	0.128	44.7 ± 1.6	0.145	0.402	0.248	50.0 ± 4.7	0.265	0.733	0.351
Average SimK (D)	SS-OCT	42.7 ± 1.1	0.089	0.248	0.163	45.0 ± 1.5	0.114	0.316	0.217	49.6 ± 4.4	0.173	0.480	0.281
Astigmatism (D)	RSC	1.2 ± 1.0	0.069	0.190	7.456	3.2 ± 1.6	0.247	0.685	5.603	3.9 ± 2.1	0.313	0.868	10.038
Astigmatism (D)	SS-OCT	1.3 ± 1.0	0.082	0.229	8.618	3.4 ± 1.7	0.161	0.447	4.413	4.3 ± 2.2	0.192	0.533	4.600
Kmax (D)	RSC	43.7 ± 1.5	0.134	0.372	0.233	51.5 ± 3.3	0.224	0.620	0.369	59.7 ± 6.8	0.480	1.329	0.620
Kmax (D)	SS-OCT	43.8 ± 1.4	0.130	0.361	0.248	50.9 ± 3.1	0.179	0.496	0.308	58.1 ± 6.1	0.283	0.784	0.377
BFS (mm)	RSC	8.0 ± 0.2	0.009	0.025	0.071	7.7 ± 0.2	0.009	0.026	0.092	7.3 ± 0.4	0.014	0.039	0.144
BFS (mm)	SS-OCT	8.0 ± 0.2	0.010	0.028	0.099	7.6 ± 0.2	0.011	0.030	0.116	7.3 ± 0.4	0.010	0.028	0.120

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