Figure 7. Results of EDEV biomarkers gene expression study. Real-time PCR analysis showing the relative changes of TNF-α (A), MMP9 (B), MUC4 (C), and DEFB2 (D) mRNA after 24 h and 48 h treatment with different tear substitutes simultaneously the induction of EDEV. A twofold change of Relative Quantification (RQ) is usually considered significant in comparison to the calibrator (CONTROL-HCE at each time point). A two-tailed Student’s t-test was used to determine statistical significance for real-time PCR. Data were considered significant at p<0.05 (*), p<0.01 (**), and p<0.001 (***).