Cataracts is a complex disease with many probable contributing factors even within a single individual. Identifying those factors and doing our best to control them may reduce our risk of developing the disease. That said, let’s outline the known risk factors for cataracts and discuss how each of us can lower our risk.
As with high blood pressure, asthma, arthritis, and most other chronic health conditions, some risk factors for cataracts are beyond our control. But specific behavioral and lifestyle choices we make, such as not smoking, do minimize our risk.
Non-modifiable risk factors
- Genetic variation. Nature is thought to have a hand in whether we develop cataracts. Studies of identical twins show that the genetic lotto determines perhaps half of our risk for cataracts. Environmental factors--that is, the modifiable risk factors outlined below--account for the rest.
- Advancing age. As we age, the risk of cataract development inevitably increases (see The Aging Eye). While we can’t turn back the calendar pages, we can change how we age. A small but intriguing study found that elderly adults who reach age 90 with their mental faculties intact are less likely to have cataracts than their peers who show signs of mental decline.
The researchers propose that lack of cataract development might be a marker, or indicator, that a person has aged well in general. This idea seems to have been confirmed by an Australian study reporting that those with cataracts have a higher rate of hearing loss and by other studies that have noted increased mortality among those with cataracts. Make no mistake--having cataracts doesn’t cause mortality. It simply may be a red flag that indicates more widespread tissue damage in the body.
- Ethnicity. Some evidence suggests that our ethnic ancestry influences the likelihood of developing cataracts. In fact, cataracts is the leading cause of treatable vision loss among black Americans age 40 and over, and it’s the number one cause of low vision among Americans of Latino, African, and European descent.
- Female gender. For reasons that remain murky, women are more likely than men to develop certain types of cataracts. According to the National Eye Institute, women also have greater difficulty getting the care they need due to lack of access transportation and other problems that affect women disproportionately.
Modifiable or partially modifiable risk factors
- Excessive sunlight exposure. A higher level of exposure to ultraviolet radiation from the sun’s rays is thought to make cataract development more likely. One published case report, for example, concludes that working at altitudes above the protective ozone layer puts airline pilots at increased risk of cataracts. Newer studies have not confirmed such an association, and research is under way to prove or disprove the link.
- Having diabetes. According to the American Diabetes Association, people with diabetes are 60% more likely than those without diabetes to develop cataracts. The condition tends to have an earlier onset and to progress more rapidly than in people with cataracts who do not have diabetes. People with diabetes are also at higher risk for treatment-related complications.
The National Institutes of Health (NIH) tracks statistics on the number of Americans with cataracts. The average prevalence for people age 65 and over is 118 people with cataracts per 1,000 population. However, the rate for those without diabetes is 107 per 1,000, while the rate among those with diabetes jumps to 182 per 1,000. The risk of onset and progression of cataracts correlates with the duration and severity of diabetes.
- Poor nutrition. Although further study is needed, vision researchers believe that a diet high in saturated fat and refined carbohydrates may be linked to the development of cataracts. They’re also investigating the possibility that low blood calcium levels may contribute to cataract development. A recent study shows that nutrient deficiencies are especially likely to contribute to the development of nuclear cataracts--that is, a cataract in the center, or nucleus, of the eye. This kind of cataract is especially detrimental to vision and is the most common form of the disease.
Another study reports that a high intake of vitamin E and the antioxidants lutein and zeaxanthin, found in dark leafy greens like spinach and kale, is associated with a significantly decreased risk of cataracts.
- Smoking. Although scientists don’t understand exactly how smoking promotes the cataract formation, there is a clear correlation between the two. The relationship is dose related, so heavy smokers have a higher risk than those who smoke less. Researchers are beginning to investigate whether environmental tobacco smoke (second-hand smoke) is a risk factor as well.
- Alcohol abuse. A higher incidence of cataracts has been found among people who chronically abuse alcohol. Having more than one drink per day also increases the risk of complications associated with cataract surgery.
Researchers have proposed several other factors that may increase the risk of cataracts, such as a family history of the disease, myopia (nearsightedness), obesity, and high blood pressure.
As you reviewed the list of modifiable risk factors for cataracts, did you notice a theme? Hard living is hazardous to your health. Moderation is the key. Here are some guidelines to keep in mind:
- Limit your sunlight exposure. The long-held belief that exposure to ultraviolet radiation contributes to the development of cataracts has been called into question by recent research. Until more studies can be carried out, it’s best to limit your exposure to bright sunlight and to wear sunglasses with UV-filtering lenses or a hat with a brim when you must be in the sun.
- Tightly control your blood sugar if you have diabetes. In addition to following general recommendations for a healthy, active lifestyle, tightly controlling your blood sugar will reduce your risk of the onset and progression of cataracts.
- Follow a healthy diet. New research shows that a diet containing adequate amounts of protein, vitamin A, thiamin (vitamin B1), riboflavin (vitamin B2), and niacin (vitamin B3) may help protect your eyes against development of nuclear cataracts. The B vitamins are found in whole, unprocessed foods such as beans, potatoes, meat, turkey, molasses, and bananas.
Unfiltered beer is an unexpectedly rich source of B vitamins because it contains brewer’s yeast, which has a high content of B1, B2, B3, and other B vitamins. Even so, you should drink beer and other alcoholic beverages only in moderation (see below).
- Stop smoking or don’t start. Smoking is so closely linked with eventual cataract development that the surgeon general’s warning label on cigarette packages now includes cataracts. (So many diseases are caused by smoking, though, that they can’t all be printed on a single package, so the list rotates.) The good news is that the threat of cataracts and other grim diseases recedes when you quit smoking. The risk continues to drop the longer you remain smoke-free.
- Use alcohol only in moderation. You should limit your intake to no more than one drink a day for women or no more than two drinks a day for men.