More than 22 million Americans—mostly senior citizens, including half of all people in the United States older than 80—have trouble seeing because the lenses of their eyes have cloudy spots, or cataracts. Cataracts are largely a consequence of the aging process; as tissue in the eye loses flexibility and starts to break down, bits accumulate and block your vision. In addition to age, risk factors for cataracts include type 2 diabetes, smoking, high blood pressure, obesity, excessive drinking, excessive sunlight, and use of corticosteroids. There is also evidence of a hereditary aspect, meaning a family history of cataracts puts you at greater risk.
When this clouding happens, it affects your ability to see. In particular, people with cataracts may experience blurred vision, double vision, dimmed vision, colors that are faded or too yellow, a halo effect around lights, sensitivity to glare, and poor night vision. If your corrective lens prescription changes often or drastically, that may also be a sign of cataracts, and your optician may decide to test; you should always see a doctor if you have double vision or unusual blurriness.
The sooner cataracts are found, the better able doctors are to treat them, so people over 40—earlier with risk factors—should get tested regularly. To look for cataracts, a doctor will use drops to dilate your eyes to get a better look, and then use a device called a slit-lamp to shine intense light on successive small portions of the iris, cornea, and retina in order to look for abnormalities. Eye surgery is the only current treatment for cataracts, but the smaller the cataract is, the more successful the surgery is likely to be.
Fortunately, there are steps you can take to prevent cataracts. Quitting smoking and cutting back on drinking help, as does maintaining a healthy weight. If you have type 2 diabetes, see your doctor regularly and follow their instructions so as to keep it well-controlled. A lot of things that are good for overall health are specifically good for preventing cataracts as well. Antioxidants and omega-3 fatty acids, for example, are often recommended as important nutrients, and studies have found that among their benefits is protecting vision. Protecting your eyes from ultraviolet radiation is important, but don’t hide indoors, because runners have a lower incidence of cataracts than non-runners in a 2009 study.