Eye do’s and don’ts

When we think about protecting our health, we often think about preventing a heart attack, keeping mentally sharp, or maybe doing something to reduce our risk of getting cancer. We hardly look and stop to think that good vision is often a critical part of overall health, too. In recent years, researchers have investigated what can be done to protect the eyes. Here is a summary of some of these findings.

• Alcohol. The retina that lines the back of the eye transforms light into the array of nerve impulses that the brain registers as vision. To pull this trick off, it needs to be supplied with ample amounts of nutrients and oxygen from the blood. Just as narrowed, diseased blood vessels, or vascular disease, can lead to heart problems and stroke, it’s believed that they might also lead to eye-disease, particularly age-related macular degeneration (AMD), one of the leading causes of blindness in people age 60 and over. It is called macular degeneration because it involves loss of the central part of the field of vision, which is controlled by a tiny part of the retina called the macula. Health researchers are testing whether any of the diet and lifestyle choices related to vascular disease risk might apply to eye diseases, too.

One candidate has been alcohol, which a number of studies have shown protects against heart disease when consumed in moderate amounts. Hopes were buoyed by a 1998 study that found AMD was less common among moderate wine drinkers. Recent study results have sent a mixed message, however. An analysis of the Nurses’ Health Study, which tracked the health and habits of 120,000 registered nurses for over two decades, found that low to moderate alcohol consumption was not protective against age-related macular degeneration. The study was published in the May 2000 issue of the Archives of Ophthalmology.

Drinking alcohol in moderation helps increase "good" HDL cholesterol level and may make your blood less likely to clot. But don’t depend on it to protect your eyes.

• Aspirin. When researchers looked at the data on arthritis sufferers who took aspirin, they noticed a low rate of cataracts. That observation and others like it kindled interest in aspirin use as cataract protection. But studies of the link have been disappointing, including one published by Harvard researchers in the March 2001 issue of the Archives of Ophthalmology. Following 21,000 doctors who were originally part of a randomized trial of aspirin but then elected to keep on taking it, these investigators found that an aspirin habit offered no special protection from cataracts over a 15-year period.

Taking a baby aspirin each day is a good insurance policy for cardiac health, but the coverage doesn’t extend to your eyes.

• Blood pressure. Because of the relationship between vascular and retinal health, it’s not surprising that high blood pressure might threaten vision. Increased blood pressure can cause small blood vessels to burst and bleed into the retina. It might also hasten the development of atherosclerosis, which in some circumstances can lead to infarcts, tiny blockages that cut off blood supply. Studies have shown that high blood pressure in people with diabetes increases the risk of diabetic retinopathy, diseased retinas in people with diabetes.

• Eye exams. Eye problems like cataracts are obvious because they affect our vision. But others sneak up on us and without a regular exam, you might miss out on early treatment. The prime example is glaucoma, a build-up of pressure in the eyeball that can damage the optic nerve and cause blindness. If they catch it early, doctors can hold glaucoma in check with a variety of eye drop-based medicines, laser treatments, and other procedures. Eye-health organizations once advocated widespread screening programs for glaucoma. Now, many prefer to focus on people in high-risk groups. People in their 70s and 80s fall under that category. Researchers at the Mayo Clinic recently found that the most common type of glaucoma was three times higher among people in their 70s than among those in their 60s.

People ages 40-64 should get an eye exam every two to four years. Starting on your 65th birthday, you should see an eye doctor every one to two years. Sticking to this schedule is doubly important for people at high glaucoma risk.

• Lutein. Lutein may be the hottest topic in preventive eye health. Companies are hawking lutein supplements on the Web. Centrum, a large supplement manufacturer, has put it in multivitamins for seniors, claiming that it helps maintain healthy eyes.

Lutein is one of 40-50 carotenoids found in the diet. Carotenoids are pigments, compounds that confer color. Betacarotene, for example, is the carotenoid that makes carrots orange. Lutein, a yellow pigment (luteus is Latin for yellow), is abundant in egg yolks and dark green leafy vegetables.

Researchers think diets high in lutein might be good for the eyes for two reasons. First, a number of studies have suggested that people with lutein-rich diets have lower rates of macular degeneration. Second, lutein and a closely related compound, zeaxanthin, are the only carotenoids found in the pigment of the macula. Researchers believe they are helpful there, absorbing the short, energy-packed waves of ultraviolet B (UVB) light and sponging up free-radical molecules, both of which harm retinal tissue.

So, should you take a lutein supplement? The fact is that most of us don’t eat nearly enough leafy green vegetables and that justifies supplementation. But the track record on large doses of single-nutrient supplements is not very good. Megadoses haven’t been as effective as hoped. In some cases they even appear to cause harm.

To increase your lutein consumption, start making a conscious effort to eat more leafy green vegetables. Consider taking a multivitamin that contains lutein, particularly if you have a family history of macular degeneration.

• Smoking. You can add the risk of macular degeneration to the long list of reasons to stop smoking or never to start. When researchers recently analyzed the results of three of the world’s largest eye-disease studies, smoking was the only risk factor, apart from age, which was consistently associated with age-related macular degeneration.

• Sunglasses. It makes sense that the sun would be hard on the eyes, and researchers have found that heavy sun exposure is connected with cataracts and macular degeneration. Johns Hopkins researchers found a very high rate of cataracts among watermen, which they blamed on constant exposure to bright sunlight. It is always debatable whether a finding about an intense occupational exposure applies to everyday life. Even so, most ophthalmologists recommend that people wear sunglasses. Some think that orange-, red-, and amber-tinted lenses are best because they block more of the blue side of the sunlight spectrum, where the wavelengths are shorter and more powerful. Others say just go for dark lenses. You may get some added comfort from polarized lenses, which work by filtering light, which is normally scattered into planes. They are effective at cutting glare.

• Vitamins. Animal studies show that shortages of vitamins A and E are bad for the retina, but that doesn’t mean that large doses of these or other vitamins are good for human eyes. Several of the long-term eye-disease investigators have suggested that vitamins A, C, and E are protective against eye disease. Others, such as the multi-center Eye Disease Case-Control Study, have shown no effect, or, in the case of vitamin C, protecting only when it is consumed in foods.

The middle-of-the-road approach is to steer your diet towards fruits and vegetables and to take a multivitamin for insurance.