**1. Introduction**

In this chapter, I described several studies on the lipid peroxidation of membrane phospholipids in retina. Particular emphasis is placed on the molecular modifications of very long chain polyunsaturated fatty acids associated with protein changes during peroxidation of photoreceptor membranes. Retina possesses membranes with high content of polyunsaturated fatty acids. Reactive oxygen species begins chain reactions of lipid peroxidation which damage the retina, especially the membranes that play important roles in visual function. Furthermore, biomolecules such as proteins or amino lipids can be covalently modified by lipid decomposition products. In retinal membranes, peroxidation of lipids is also usually accompanied by oxidation of membrane proteins. In consequence, lipid peroxidation may alter the arrangement of proteins in bilayers and by that it interferes with their physiological role on the membrane function.
