Described as a natural clouding of the eye lens, cataracts are pretty common, affecting about 20 million people worldwide.1

Cataracts are actually considered an inevitable part of aging and are widespread among people ages 55 years and older. In fact, half of all Americans have them—or have had cataract surgery—by age 80. In other words, if you live long enough, you will likely develop cataracts.

What's worse, if left untreated, cataracts can lead to blindness. Cataracts are already the leading cause of vision loss in adults over age 55 and the most common cause behind blindness worldwide. (For more, see What Are Cataracts?)

The good news, however, is that treatment for cataracts is successful; more than 97 percent of the 3 million-plus cataract surgeries performed each year in the United States are considered successful.

In fact, about 95 percent of patients are able to restore their full pre-cataract distance vision after undergoing the standard intraocular lens (IOL) procedure.

The Aging Eye

Without Cataract: A normal, healthy lens absorbs and focuses light accurately onto the retina creating a crisp clear view of objects near and far.

Early Stage/Mid Stage Cataract: As the eye ages, the lens naturally becomes less flexible and more opaque. This allows less light to enter and that light to be diffused.

Late Stage/Advanced Cataract: As this happens, vision has less depth-of-field and becomes more blurry and less colorful, eventually resulting in total loss of vision.

Next: Causes of Cataracts


  1. Brian G, Taylor H. Cataract blindness—challenges for the 21st century. Bulletin of the World Health Organization. 2001;79:249-256. Accessed October 20, 2010.