A cataract is a clouding of the crystalline lens, within the eye, or the envelope that holds the lens in place. Cataracts may be caused by trauma, high blood pressure, diabetes, advanced age and UV rays from the sun. To prevent the condition, diet and lifestyle are factors. For example, cataracts are more common among smokers. Wearing UV blocking sunglasses may be beneficial, particularly if you fly or spend a great deal of time outdoors.

When it comes to diet, higher intakes of carotenoids are negatively associated with the condition. In other words, people that eat more fruits and vegetables are less likely to develop cataracts with age.

Carotenoids are pigments responsible for the vibrant colors of plant foods. They are either carotenes or xanthophylls. Lutein and zeaxanthin are xanthophylls.

Age-related macular degeneration or AMD is the leading cause of blindness among the elderly. Unlike cataracts, which are relatively easy to treat by removing and replacing the crystalline lens, there is no effective treatment for AMD, but it may be preventable.

The macula is an area in the retina that is responsible for central vision. The retina is connected to the brain via the optic nerve. Images of the things that are in front of you appear on the retina, as they would on a movie screen. The image is transmitted to the brain. That's how we recognize the things and people that we see.

Regular eye exams reveal changes that can lead to AMD. For example, yellow deposits form on the macula long before vision is affected. When these changes are seen, people may be able to slow or stop the progression of the disease by making changes in their diet and lifestyle, and by increasing their intake of xanthophylls. When the yellow deposits are seen by and optometrist or ophthalmologist, he or she will often recommend lutein and zeaxanthin supplements, because studies have shown they reduce the risk of blindness in people that have AMD.

Xanthophylls make up the retina. They absorb high energy blue light which is believed to be one of the causes of AMD and cataracts. UV rays of sunlight are invisible. High energy blue light is visible sunlight. Some exposure to the sun is healthy, but overexposure plays a role in both of these eye diseases, as well as skin cancer, wrinkles and the visible signs of aging.

Many optometrists and ophthalmologists recommend increased nutrient intake to all of their patients, either by making dietary changes or by taking supplements. If you are like most people, you try to eat five servings of vegetable every day, as well as a variety of fruits and berries, but no diet is perfect. Nutritional supplements are an easy way to insure that you are getting enough lutein, zeaxanthin, and other carotenoids on a daily basis.