Carotenoids in the human macula and whole retina

The carotenoid pigments in the whole human retina and in the macular region were measured quantitatively by high pressure liquid chromatography (HPLC). Approximately a five-fold larger amount of carotenoids was found in the human macula (35-120 ng) than in previously reported work. The dominant carotenoids in the whole retina are lutein and zeaxanthin. Zeaxanthin is concentrated in the macular region, whereas lutein is dispersed throughout the entire retina. Contrary to prior reports, substantial quantities of both carotenoids are present in the infant retina. Increasing variability is observed in carotenoid levels between individuals with advancing age, and some older individuals show very high whole retina carotenoid levels. These quantitative studies were made possible by synthesis of a new, stable carotenoid internal standard. Carotenoids have been proposed to be potent antioxidants, protecting membrane lipids from toxic peroxidation reactions. The method presented in this study will facilitate quantitative investigations of the association between carotenoid levels and health and disease of the retina.