GDF15 and glaucoma: The GDF15 levels in AH and serum samples from POAG patients were significantly elevated (p < 0.001 and p < 0.011, respectively) by >9 fold and 1.5-fold, respectively, compared to the respective samples derived from non-glaucoma (cataract) patients based on the Wilcoxon rank sum test of difference between medians (Figure 1, Table S2).