For generations, mothers have advised their children to eat their carrots for the sake of their eyes. Indeed, carrots do contain compounds that are vital to vision. But today’s moms and others wanting to eat for eye health should know that eating for better vision is not just about carrots anymore.
Researchers have been homing in on evidence that certain dietary habits may help stave off two common degenerative eye diseases: age-related macular degeneration (AMD), the most common cause of legal blindness and vision impairment in older Americans, and cataract, a condition affecting more than 20 million Americans. What you eat can also help to control blood glucose levels, which is important to reducing the risk of developing diabetic retinopathy, a common eye complication of diabetes.
An in-depth look at nutritional strategies for healthy eyes follows, but first it’s helpful to understand a little more about these common eye diseases.
Age-related macular degeneration
According to the National Eye Institute, more than 1.7 million older Americans have advanced-stage age-related macular degeneration. Because the risk of developing AMD rises with age — the condition is rare in people under 60 — the number of people diagnosed with the disease is expected to increase sharply as the baby-boom generation ages.
The macula of the eye is a tiny region at the center of the retina, the thin tissue that lines the eyeball. Light-sensitive cells in the macula are responsible for sharp vision, the kind needed for everyday activities such as reading, driving, and watching television. Scientists are not sure exactly how the most common form of macular degeneration starts, but over time these cells can break down. In most cases, this breakdown happens slowly, gradually leaving less of the macula to handle light properly. With increasing degeneration, vision can blur and a blind spot can develop in central vision. There are no proven treatments to stop this progression, although new research indicates that a specially formulated high-dose supplement may be helpful (see below). Smokers, those with a family history of AMD, and women are at an increased risk for AMD. Whites are more likely to lose their vision from AMD than African-Americans. High cholesterol may also increase one’s risk for a rarer and more rapidly damaging form of AMD.
The second common eye disorder, cataract, affects more than half of all Americans age 65 and over. A cataract is a cloudy spot in the lens of the eye. In the healthy eye, the lens, composed of water and protein, is transparent. For reasons that are not fully understood, this protein can clump together, forming a cloudy spot that causes light to be distorted as it passes through the lens.
Most cataracts are related to aging, and more than half of all Americans age 65 and over have a cataract. In addition to age, diabetes can also cause proteins in the lens to clump. People with diabetes, therefore, are more likely than the general public to form cataracts and often develop cataracts at a younger age. Symptoms of cataracts include blurry vision, reduced night vision, fading of colors, and problems with glare.
Besides diabetes and advancing age, smoking and long-term exposure to the sun’s ultraviolet rays are believed to increase the risk for developing a cataract. Medicines such as steroids can also cause cataracts.
Attention has also been focused on the biological process of oxidation as one of the factors that may lead to both AMD and cataract. This in turn has raised interest in the potential of antioxidants, compounds that appear to mitigate some of the damage caused by oxidation.
Another area of research has concentrated on diet, specifically diets high in green leafy vegetables.