H2O2 induces RGC apoptosis in vitro. RGCs were treated with 0–500 μM H2O2 for 12 h (A, C) or 500 μM H2O2 for 0–24 h (B, D). Cell viability (A, B) and cell apoptosis (C, D) were determined using the MTT assay and the annexin V‐FITC flow cytometric apoptosis assay, respectively. n = 3, *P < 0.05 vs. control.