Long-term exposure to air and light generates little oxygen fragments, called oxidants, that damage the eyes. Choosing a diet rich in the antioxidant nutrients, such as vitamin C, vitamin E, selenium, beta carotene, lutein, and zinc, fortifies the eyes against this damage and helps protect against the development of both cataracts and macular degeneration. People with high levels of these antioxidants are at lowest risk of vision loss later in life.
For example, vitamin C is the antioxidant found in oranges, strawberries, and other fruits and vegetables. The eye naturally stockpiles vitamin C to levels 20 times and higher than those found in the blood. The high concentration of vitamin C in our eyes might be an adaptation that protects against the damaging UV rays in sunlight.
A host of other antioxidant-rich compounds, called phytonutrients, in colorful fruits and vegetables also are sight savers. Lutein is one of them, a phytonutrient in dark green leafy vegetables, such as spinach. When people consume as little as 10 milligrams of lutein daily (the amount found in 1 /2 cup of spinach), their levels of lutein increase in the blood and eyes, and they are less prone to vision loss. If they do develop vision problems, such as macular degeneration, the disease is less likely to progress to advanced stages.
Dietary fat also might play a role in the development of age-related vision loss. Saturated fats in meat and fatty dairy products might increase risk up to 80%, while the healthy fats, especially the omega-3s in fatty fish, possibly lower risk for both cataracts and macular degeneration.