Lutein is an antioxidant and in the carotenoid family. It is a naturally occurring fat soluble pigment found in plants and vegetables. It is the main carotenoid present in the central area of the retina called the macula. Lutein may act like a filter to protect the macula from potentially damaging types of light. Thus lutein appears to be associated with protection from age related macular degeneration which is the the leading cause of blindness and eye problems in older people.
Macular Degeneration
People who eat more lutein rich foods or take lutein supplements appear to be at lower risk of macular degeneration. One study found that adults with the highest dietary intake of lutein had a 57% decreased risk of macular degeneration compared with those people with the lowest intake, and of the carotenoids, lutein/zeaxanthin are most strongly associated with this protection.

Cancer Protection
Diets rich in carotenoids have been associated with a lower risk of developing many kinds of cancer. Recent studies have also specifically targeted carotenoids other than beta-carotene (like Lutein, Alpha-carotene, Cryptoxanthin, and Lycopene) as having anti-cancer effects.