Therapeutic Uses Evidence suggests that people who eat foods containing lutein are less likely to develop macular degeneration or cataracts , the two most common causes of vision loss in adults. However, these were observational studies, in which people simply eat what they please and researchers follow them to see what illnesses they develop. Because lutein is found in vegetables that may also contain other helpful substances, we don't know for sure if it is the lutein itself that is providing the benefit. We really need studies in which some people are given pure lutein and others a placebo, but as yet they have not been performed. However, there are reasons to believe that lutein may indeed play an important role in protecting the eyes.
Macular degeneration consists of injury to the macula, and leads to a severe loss in vision.
One of the main causes of macular degeneration appears to be sun damage to the sensitive tissue. Lutein appears to act as a natural eyeshade, protecting the retina against too much light. This may explain why higher dietary intake of lutein appears to reduce the risk of this common cause of blindness in adults. Besides protecting the macula, lutein may also shield the lens of the eye from light damage, slowing down the development of cataracts. Furthermore, lutein fights free radicals.