Figure 6. Correlation of OD and OS tear EGF with corresponding OD and OS clinical measurements of tear production and ocular surface integrity in DED patients. EGF levels correlated negatively with rose Bengal and fluorescein staining tests (measuring ocular surface integrity) and positively with Lysozyme and Schirmer tests (measuring tear production). EGF values are expressed in pg/ml in a 100× scale. Spearman ranked correlation test was used and the strength of correlation between variables was determined by the Spearman's rho correlation coefficient. EGF, epidermal growth factor; OD, right eye; OS, left eye.