Figure 2. Quantile-quantile (Q-Q) plot of primary angle-closure glaucoma (PACG) genome-wide association (GWA) analysis. A: Scatter plot of the −log10 (p values) expected under the null hypothesis of no genetic association versus the observed −log10 (p values) for all subjects before correction for population stratification using multidimensional scaling analysis (MDS) generated covariates, and (B) following correction for population stratification using MDS generated covariates. A significant improvement in the initially observed deviation from normal distribution of all p values as a result of correcting for relatedness and population stratification effects is observed.