Figure 1. Effect of H₂O₂ on cell viability and morphological alterations. A: The ARPE-19 cells were incubated with concentrations of 0–500 μM H₂O₂ for 24 h. Cell viability was determined by an MTT assay. B: Phase contrast photomicrographs of ARPE-19 cells. ARPE-19 cells were treated with 0, 200 μM H₂O₂, 1 μM CP55,940, 1 μM CP55,940 plus 200 μM H₂O₂ for 24 h (Magnification: 100X).