Everyone wants to remain vibrant and independent as they age, to continue driving, playing tennis, living on their own. But one day you notice your vision has grown cloudy. Cataracts can creep up so silently that a person may not even know it's there initially. More than half of all Americans age 65 and older have a cataract.

And you don't have to be a senior citizen to develop cataracts. In fact, people can have an age-related cataract in their 40s and 50s, at this age most cataracts are small and on the outer edge of the lens and doesn't cause vision problems. In the early stages, stronger lighting and eyeglasses may lessen vision problems. It is after age 60 that most cataracts steal vision.

The lens lies behind the iris and pupil and is composed mostly water and protein, which allows light to pass through. It works much like a camera lens. It focuses light onto the retina at the back of the eye, where an image is recorded. The lens also adjusts the eye's focus, letting us see things clearly both up close and far away. As we age, some of the protein may clump together and start to cloud a small area of the lens.

This is a cataract. In its early stages, a cataract may not cause a problem. Cataracts tend to grow slowly, so vision gets worse gradually. Over time, the cataract may grow larger and cloud more of the lens, less light reaches the retina, and your vision may become dull and blurry. As the cataract gets bigger and clouds more of the lens, it is increasingly difficult to read and do other normal tasks and you may need to change eyeglass prescriptions frequently.

A cataract may make light from the sun or a lamp seem too bright, causing a glare. Also, colors may not appear as bright to you as they once did. The word "cataract" means waterfall. For people with cataract, it is like trying to see through a waterfall.

For the early stages of a cataract, vision may improve by using different eyeglasses, magnifying lenses, or stronger lighting. Once you notice a change in vision that interferes with everyday activities, work, driving, reading, you may need surgery to replace the cloudy lens.

An eye exam is needed to detect cataracts. You will be asked to read the letter eye chart, visual acuity test, to determine the amount of visual loss. Next the pupil is widened with eyedrops to allow your eye doctor to see more of the lens and retina and look for other eye problems.

During the examination, the ophthalmologist will also carefully measure the shape, size and general health of the eye to determine whether a lens implant will be effective. Some people cannot have a lens implant. There may have problems during surgery, or maybe there are other eye diseases. In these cases, a soft contact lens or glasses may be the best option. Glasses, while used for years, have drawbacks.

Their extreme thickness makes them unattractive and heavy. Magnification and distortion of the visual image causes objects to appear closer and 25 percent larger than they are. Peripheral vision may be reduced. Contact lenses provide fairly good vision, but many elderly people have trouble inserting, removing and cleaning them.

During the surgery your cloudy lens is replaced by a plastic intraocular lens (IOL) in an hour long procedure. A small incision is made on the side of the cornea, the clear, dome-shaped surface that covers the front of the eye. A tiny probe that emits ultrasound waves is used to soften and break up the cloudy center of the lens so it can be removed by suction. Most cataract surgery today is done by phaco, which is also called small incision cataract surgery.

With extracapsular surgery, a slightly longer incision is made on the side of the cornea and the hard center of the lens is removed. The remainder of the lens is then removed by suction. An IOL is a clear, artificial lens that requires no care, it is not felt by you or noticed by others. Within a few days of the surgery, most people are back enjoying their life again. At a time when people are living longer then ever before, and looking forward to many years of active life, the sense of sight becomes even more important.

A cataract won't spread from one eye to the other, although many people develop cataracts in both eyes.

No one knows for sure what causes cataracts. There may be several causes, including smoking, diabetes, and excessive exposure to sunlight. Or, it may be that the protein in the lens just changes from the wear and tear it takes over the years.

The most common symptoms of a cataract are:

These symptoms can also be a sign of other eye problems. If you have any of these symptoms, check with your eye care professional.

People over the age of 60 are at risk for many vision problems. If you are age 60 or older, you should have an eye examination through dilated pupils at least every 2 years. This kind of exam allows your eye care professional to check for signs of age-related macular degeneration, glaucoma, cataracts, and other vision disorders.