Hypothyroidism is Not Associated with Keratoconus Disease: Analysis of 626 Subjects

Figure 2

Receiver-operating characteristics (ROC) curve for estimating the TKC. A linear estimation equation was used to determine the best threshold for distinguishing between keratoconus and normal eyes with the ROC curve. The area under the ROC curve is 0.74 (arrow). The maximum Youden index is marked with an arrow on the graph. The Youden index is (sensitivity + specificity − 1) 0.422.