Figure 2.

The reactive oxygen species and the antioxidant systems in the lens. H₂O₂-generated by the dismutation of superoxide anion or by the reaction between ascorbate and Fe³⁺ can be degraded by several pathways. These include Catalase, glutathione peroxidase and the Fenton reaction. The decrease in the SH/S-S ration by oxidation can be reversed by the glutathione reductase (GR)-pentose phosphate shunt cycle and by thioltransferase (TTase). These mechanisms protect the lens from oxidative damage. GR: glutathione reductase; GPx: glutathione peroxidase; SOD: superoxide dismuase; TTase: thioltransferase. Reprinted with permission from Lou, PRER (2003); Copyright Elsevier 2003 [8].