Figure 1. Zinc (Zn²⁺), or oxidative stress induces an increase in intracellular free zinc concentration ([Zn²⁺]_i). Cultures of Müller, ARPE-19, and 661W cells were pre- or post-loaded with 5 μM FluoZin3 AM and exposed to 60–300 μM Zn²⁺, 30–60 μM ethacrynic acid, and 200–400 μM H₂O₂, as indicated. Representative photomicrographs (n=6) of identical exposure were taken at the times shown.