KL and keratoconus: Figure 3A shows the risk score (top) and survival status (bottom) for each patient in the training group. Patients with high-risk KC had a worse OS (Figure 3B). KL expression was significantly decreased in patients with high-risk KC (Figure 3C). Principal component analysis (PCA) revealed that low-risk KC patients could be distinguished from high-risk KC patients (Figure 3D).