Our eyes work a lot like a camera. Light focuses through a lens behind the  pupil  onto the retina which is a layer of light-sensitive cells at the back of the eye.   Over time, the lens of our eye can become yellowish or cloudy, preventing light rays from passing clearly through to the retina.  This loss of transparency or cataract formation may be so mild that vision is barely affected, or it can be so severe that no shapes or movements are seen—only light and dark.

Eyeglasses can usually correct slight refractive errors caused by early cataracts, but they cannot sharpen your vision if a severe cataract is present.  People often describe vision with cataracts like looking through a dirty/dusty window.

The most common cause of cataract is aging. Other causes include injury, medications such as steroids, systemic diseases such as diabetes, and prolonged exposure to ultraviolet light. People who smoke seem to get cataracts earlier than non-smokers. Occasionally, babies are born with a congenital cataract.

Cataracts typically develop slowly and progressively, causing a gradual and painless decrease in vision.  Other changes you might experience include blurry vision; glare, particularly at night; frequent changes in your eyeglass prescription; a decrease in color intensity; a yellowing of images; and, in rare cases, double vision in one or both eyes.

Reducing your exposure to ultraviolet light by wearing a wide-brimmed hat and sunglasses may reduce your risk for developing a cataract, but once one has developed, there is no cure except to have the cataract surgically removed.  There are no magical drops or diets that will reverse cataract formation.

With a routine, outpatient surgical procedure, an ophthalmologist can remove the cataract by making a small incision in the cornea at the front of the eye.   Once the cataract is removed,  a plastic intraocular lens (IOL) is inserted just behind the pupil.   IOLs can be monofocal (fixed-focus for a pre-set distance) or multifocal, which allows focused vision at many distances.  There are several choices for multi-focal implant lenses including one where you can actually change its focus from far to near and back to far again.

The time to have cataract surgery is when it affects your normal lifestyle.   Cataracts can blur vision and worsen glare from lights. They can make it difficult to drive safely, perform household tasks and maintain a normal level of independence.  Cataract surgery is a very successful operation that fortunately continues to evolve for the better.

3.6 million people have this procedure every year in the United States, and 98% have a successful result; in the vast majority of cases, vision and quality of life are much improved.