Lutein and zeaxanthin, found together in many vegetables, are potent antioxidants. They occur in high concentrations in the eye, including the lens, retina, and macula. For that reason, lutein and zeaxanthin are thought to be crucial to healthy vision.
Eye-related benefits: Lutein and zeaxanthin protect the eyes from harmful high-energy light waves, such as some ultraviolet rays in sunlight. Studies suggest that high levels of lutein and zeaxathin in eye tissue are associated with better vision, especially in dim light or where glare is a problem. Diets rich in these two antioxidants appear to protect against age-related eye diseases. For example, one study found that people with diets high in foods rich in zeaxanthin -- particularly spinach, kale, and broccoli -- are up to 50% less likely to develop cataracts. A major study is under way to find out if supplements containing lutein and zeaxanthin reduce a person's risk of developing the eye disease macular degeneration. Researchers are also looking into whether these supplements can slow the progression of macular degeneration if you already have it. A test called macular pigment optical density is now being used by eye care specialists to measure levels of lutein and zeaxanthin in eye tissue.
During a cornea transplant, an eye surgeon removes a portion of your cornea and replaces it with a new section of cornea from a donor.
The procedure is also called a corneal transplant or a keratoplasty. About 40,000 cornea transplants are performed in the U.S. every year.
You may need a cornea transplant if your cornea no longer lets light enter your eye properly because of scarring or disease.
Note: Many studies combined lutein and zeaxanthin with other nutrients, such as vitamins C and E, and beta-carotene. It's possible that the combination of nutrients may be more helpful than any single nutrient.
Recommended daily allowance: No RDA has been set for lutein or zeaxanthin.
Recommended level for eye health: The American Optometric Association recommends 10 mg/day of lutein and 2 mg/day for zeaxanthin.
Safe upper limit: Researchers have not set an upper limit for lutein or zeaxanthin.
Potential risks: Lutein and zeaxanthin in excess may turn the skin slightly yellow. There are no serious side effects associated with them.