Lutein acts to filter and shield harmful blue light from the eye and protects against age-related macular degeneration, the leading cause of blindness in people over 65. One study has indicated that adults with the highest dietary intake of lutein had a 57% decreased risk of macular degeneration compared to those with the lowest intake.

Lutein is one of 600 naturally occurring fat-soluble antioxidant carotenoid biochemicals that are found in green leafy vegetables such as spinach, kale, collard greens, romaine lettuce, leeks and peas. The central area of the retina in humans and primates is called the macula and contains lutein as the primary carotenoid. Lutein is a special kind of antioxidant in that lutein is used by organisms as a regular antioxidant, but also it absorbs blue light, meaning it can protect against some forms of light damage to the eye itself, sort of like having a natural pair of sunglasses. Generally, when the color of someone's eyes starts to fade, it is not directly related to aging itself, but due to the bodies' loss of lutein that occurs when we age if we do not to something to counteract it.

Lutein builds a reserve of sorts in the eye to assist in long-term eye health. Even if you are not currently suffering from any vision problems, lutein is a worthwhile supplement to preserve the vision you currently have and, in some instances, even improve your visual acuity. Think of lutein doing for your eyes what sunscreen and moisturizer does for your skin - if you start using it while you are young, you will preserve your skin looking young and supple. The same is true with your vision; if you are 50, you would love to have the vision you had at 25. There are no known negative side effects of lutein unless taken in excessive doses, which causes a bronzing of the skin.