Table 4.

The receiver operating characteristic area under curve (ROC-AUC) in each parameter to separate normal eyes from forme fruste keratoconus (FFKC) eyes.

		ROC-AUC	95% CI
Anterior Surface area	5 mm	0.449	0.226–0.672
	6 mm	0.577	0.364–0.790
	7 mm	0.586	0.377–0.795
Posterior Surface area	5 mm	0.678	0.467–0.890
	6 mm	0.672	0.472–0.873
	7 mm	0.655	0.454–0.857
As/Ps	5 mm	0.948	0.882–1.000
	6 mm	0.797	0.645–0.948
	7 mm	0.732	0.550–0.915
Ab/Pb	5 mm	0.742	0.552–0.931
	6 mm	0.751	0.569–0.933
	7 mm	0.729	0.546–0.913

ROC-AUC: the receiver operating characteristic area under curve, CI: confidence interval, As: anterior surface area, Ps: posterior surface area, Ab: anterior best-fit sphere, Pb: posterior best-fit sphere.