Sighted: Foods for better vision

While cataracts are thought by many to be the primary cause of vision loss in the elderly, a little-known eye condition called age-related macular degeneration actually ranks as the leading cause of irreversible blindness among older Americans. The disease afflicts one out of three people over age 75. But it now looks as though simply eating a diet rich in spinach, collards, kale, and other greens may help stave it off. The connection, judging by new research, appears to be that certain substances in leafy vegetables and other produce are found in the portion of the eye subject to damage from age-related. macular degeneration.

That portion is part of the retina--a paper-thin tissue that lines the back of the eyeball. At its center is a tiny area called the macula, which is made up of millions of cells that together produce the sharp vision needed to read and see objects clearly. Over time, for reasons scientists have yet to pinpoint, parts of the retina and the macula become diseased, thereby causing the blurred vision symptomatic of age-related macular degeneration, or AMD. As the disease progresses, tiny, fragile blood vessels begin to develop in the retina, where they often leak blood and fluid that damages the macula even further. At this stage, loss of vision can occur within weeks or months.

But green leafy vegetables, or two particular compounds they contain, may play a role in preventing the process. Dubbed lutein and zeaxanthin, these substances are carotenoids--members of the family of yellow and red pigments that includes beta-carotene. Scientists speculate that by accumulating in the retina and filtering out certain types of rays of light that may damage it, they may leave both the retina and the macula less vulnerable to the degeneration that leads to AMD.

Supporting the theory is a nationwide study of more than 850 people, which found that those who reported eating the most carotenoid-rich foods, including everything from carrots to tomatoes, ended up with nearly half the estimated risk of falling victim to AMD as those whose diets fell far short in such vegetables. Even more telling, the group of participants who typically ate lutein-and zeaxanthin-rich greens like spinach or collards two to four times a week were only about one half as likely to suffer AMD as those who ate them less than once a month.

To be sure, the preliminary research does not provide definitive proof of cause and effect. Still, until more results come in from studies currently under way, it's certainly not a bad idea to make an effort to eat generous amounts of leafy greens and other vegetables such as broccoli and winter squash, all of which supply lutein and zeaxanthin as well as a host of nutrients.

A WORD ON DIAGNOSIS
Age-related macular degeneration most often strikes after age 60. The only early symptom tends to be blurred vision, but as more and more cells of the macula are destroyed, people may begin to see a small blind spot in the middle of their field of vision. As the disease becomes increasingly severe, straight lines often appear crooked.

You can use the grid to keep an eye on your own vision at home. While covering one eye, look at the dot in the center. Then do the same with the other eye. If in either case the lines surrounding the dot appear wavy, blurry, or distorted, you should have your eyes examined by an ophthalmologist

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