VWF and Polypoidal choroidal vasculopathy: AMD, age-related macular degeneration; PCV, polypoidal choroidal vasculopathy; PLS-DA, partial least squares discriminant analysis; LPC, lysophosphatidylcholine; PC, phosphocholine; ROC, operating characteristic curve; AUC, area under the receiver operating characteristic curve; vWF, von Willebrand Factor.