Table 3. The cut-off point, specificity, and sensitivity values identified by the different reference surface.

	Thinnest point	AUROC	SE	P	Cut-off (μm)	Se (%)	Sp (%)	PLR	NLR
KC vs KC suspect + normal	Ant. BFS	0.967	0.013	0.000	4.97	100	80	4.88	0
	Ant. BFT	0.969	0.013	0.000	8.83	84	96	23.16	0.17
	Post. BFS	0.953	0.017	0.000	14.92	84	94	13.90	0.17
	Post. BFT	0.961	0.017	0.000	16.44	86	98	35.71	0.14
KC suspect vs Normal	Ant. BFS	0.836	0.047	0.000	3.73	76	89	6.96	0.27
	Ant. BFT	0.925	0.031	0.000	4.03	81	89	7.46	0.21
	Post. BFS	0.749	0.054	0.000	9.68	54	88	6.22	0.50
	Post. BFT	0.841	0.043	0.000	10.14	60	91	6.84	0.44
KC vs Normal	Ant. BFS	0.996	0.004	0.000	4.95	100	98	46.00	0
	Ant. BFT	0.999	0.001	0.000	5.06	98	100	n.a.	0.02
	Post. BFS	0.981	0.010	0.000	9.88	95	89	8.77	0.05
	Post. BFT	0.988	0.007	0.000	11.13	93	96	21.40	0.07
KC suspect vs KC	Ant. BFS	0.930	0.026	0.000	7.76	79	92	9.75	0.23
	Ant. BFT	0.931	0.027	0.000	8.96	81	95	15.06	0.20
	Post. BFS	0.919	0.031	0.000	15.64	81	95	15.06	0.20
	Post. BFT	0.926	0.030	0.000	16.44	86	95	15.92	0.15

AUROC, area under the receiver operating characteristic curve; CI, confidence interval; KC, keratoconus; BFS, best-fit sphere; BFT, best-fit toric-ellipsoid; SE, standard error; Se, sensitivity; Sp, specificity; PLR, positive likelihood ratio; NLR, negative likelihood ratio; n.a, not applicable