There is a great deal of variability in the amount of pigment present in the back of the retina. This pigment is of course essential for light absorption, and is located just beneath and adjacent to vision receptors at the back of the retina. Individuals with really robust amounts of pigment probably have less risk of AMD - a strong correlation seems to exist. Studies suggest individuals with reduced degrees of pigment lose vision sensitivity sooner, while those with considerable pigment retain sensitivity similar to those of much younger ages. One rationale is that pigment absorbs blue light, known to particularly damaging to photoreceptors.
Smoking is known to reduce the level of macular pigments.
In fact lutein and zeaxanthin are two of the main chemicals found in macular pigments. While the body makes zeaxanthin from lutein, lutein is not synthesized at all. Intake of fruits and vegetables high in carotenoids leads to a large increase in the concentration of lutein in blood plasma. Studies in which intake of fruits and vegetables was studied found not only high concentrations proportional to intake of fruits and vegetables high in lutein but increased macular pigment as well. Alcohol intake reduces levels of antioxidants and carotenoids in blood plasma.