Figure 3: Apoptosis in HRPEpiC cells exposed to white (Ta5400°K), blue (468 nm), green (525 nm), and red (618 nm) LED lighting (irradiated cells) for 3 lightdarkness cycles (12 hours/12 hours). Apoptosis determined by the activation of caspase-3 is observed as a pink coloration around DAPI-stained cells. The white arrows indicate apoptotic cells. (A) Representative images of RPE cells maintained in darkness (negative control) and RPE cells treated with H2O2 to provocate toxicity (positive control); (B) Effects of LED lighting on human RPE cells in vitro without filter; (C) Photoprotective effects of blue light absorbing filter on human RPE cells.