Figure 2. Effect of blue light on intracellular ROS. Flow cytometric analysis of intracellular ROS levels with the oxidant-sensitive dyes DHE (A) and CM-H2DCFDA (B) in ARPE-19 cells. Cells were irradiated with 1 mW/cm² (dark bars) or 0.3 mW/cm² (light bars) for 3, 24, or 72 h. Unirradiated cells were used as negative controls. The graph displays median fluorescence intensity ratios of irradiated cells versus unirradiated controls. Bars represent mean±SD from n=5 separate experiments; The asterisk (*) indicates a p<0.05 (one-way ANOVA and Bonferroni test).