The problem with many eye diseases is that their symptoms often go unnoticed until vision loss has already occurred. The good news is that it is now possible to prevent or correct 4 of the 5 most common causes of visual impairment associated with growing older: presbyopia (inability to focus on near objects), cataracts, glaucoma, and diabetic retinopathy.
The 5th common cause of visual impairment in the elderly—age-related macular degeneration (ARMD)—is the hardest nut to crack, having as yet neither effective preventive measures nor treatments. When ARMD destroys the highly sensitive, central portion of the retina (the macula), a person loses the detailed central vision necessary for participating fully in activities of daily living such as reading, watching television, and driving.
As indicated by its name, age-related macular degeneration is rare before the age of 55; however, its incidence increases rapidly as people age, so that as many as 10 percent of people over age 85 have at least some evidence of ARMD. And while ARMD isn't always associated with severe visual loss, the disorder is estimated to be responsible for legal blindness in about 2 percent of people aged 65 and older.
Many studies, most investigating various antioxidants, have attempted to identify dietary measures that will prevent ARMD, but these have yielded contradictory results.
Two major diet-based carotenoids—lutein and zeaxanthin—have been closely studied for their possible benefits. A study reported in the September 2007 Archives of Ophthalmology found that those with the highest dietary intakes of lutein and zeaxanthin were 35 percent less likely than average to have ARMD.
But then an analysis of 9 studies and 3 clinical trials (involving a total of about 150,000 subjects) appeared in the British Medical Journal. The conclusion? Vitamins A, C, and E, as well as zinc, lutein, zeaxanthin, alpha-carotene, beta-carotene, beta-cryptoxanthin, and lycopene have little or no effect in the primary prevention of early ARMD.
Despite the lack of definite scientific evidence that dietary lutein and zeaxanthin help prevent ARMD, it makes sense to eat lots of dark green, leafy vegetables like spinach, kale, and highly colorful plant foods such as corn, which are naturally rich in lutein and zeaxanthin. Egg yolks also contain considerable lutein, but I can't recommend them because of their high cholesterol content—and I'm not enthusiastic about the widely promoted dietary supplements containing lutein or zeaxanthin, or both.
Other than age, smoking is the strongest risk factor for ARMD, so it will do you little good to eat these healthy foods if you continue to smoke.
