Figure 2. Cell viability in human retinal pigment epithelial cells with different concentrations of H₂O₂-containing medium. Human retinal pigment epithelial cells (ARPE-19) cells were exposed to various concentrations of H₂O₂ for 3 h. Cell viability was measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. No significant difference in cell viability was observed in doses of less than 500 μM H₂O₂. However, doses above 500 μM H₂O₂ caused dose-dependent retinal pigment epithelium (RPE) cell death. **p<0.01, ***p<0.001. Histograms are representative of three independent experiments. Each bar represents mean±SD (standard deviation) from three independent experiments.