Table 5. Summary of previous reports for distinguishing clinical and SKCN from normal eyes.

Author	Year	Device	Indices	Cutoff	AUC	Sensitivity	Specificity
KCN vs Normal
Sedghipour et al[18]	2012	Pentacam	KISA	-	-	0.96	100
Shetty et al[5]	2017	Pentacam	BADD	2.6	0.972	1.00	0.614
Lopes et al[19]	2018	Pentacam	PRFI	0.52	1.00	100	0.966
Degirmenci et al[20]	2018	Pentacam	CTmin	0.85	491.5	0.87	0.73
Hashemi et al[21]	2019	Pentacam	IVA	0.20	0.952	0.875	0.963
Vega-Estrada et al[22]	2019	Sirius	KVb	13.5	-	0.890	0.840
Tian et al[8]	2014	Corvis	DA	-	0.882	0.817	-
Chan et al[23]	2017	Corvis	InvRadmax	0.19	0.954	0.81	0.87
Ferreira-Mendes et al[24]	2019	Corvis	TBI	0.385	0.99	97.1	98.1
SKCN vs Normal
Ucakhan et al[25]	2011	Pentacam	PPIave	1.15	0.84	0.818	0.788
Lopes et al[19]	2018	Pentacam	PRFI	0.125	0.968	0.852	0.966
Degirmenci et al[20]	2018	Pentacam	ISV	18.5	0.88	0.80	0.80
Song et al[26]	2019	Pentacam	BADD	1.2	0.799	63.64	85.71
Heidari et al[27]	2020	Sirius	BCVf	0.245	0.877	87.7	83
Shetty et al[5]	2019	Sirius	RMS/A	0.088	0.730	0.108	0.719
Wang et al[28]	2017	Corvis	CBI	0.215	0.785	80.3	63.2
Chan et al[29]	2018	Corvis	TBI	0.16	0.925	0.844	0.824

KCN: Keratoconus; SKCN: Subclinical keratoconus; KISA: KCN percentage index; BADD: Belin/Ambrosio enhanced ectasia total derivation value; PRFI: Pentacam random forest index; CT_min: Minimum corneal thickness; IVA: Index of vertical asymmetry; KVb: Keratoconus vertex back; DA: Deformation amplitude; InvRad_max: Maximum inverse radius; PPIave: Average of pachymetric progression index; ISV: Index of surface variance; BCVf: Front Baiocchi-Calossi-Versaci; RMS/A: Root mean square per unit area; TBI: Topographic and biomechanical index; CBI: Corneal biomechanical index; SKCN: Subclinical keratoconus; AUC: Area under the curve.