The clumps of protein cloud the eye's lens. The lens is a clear part of the eye that helps to focus light on the retina, the light-sensitive tissue at the back of the eye. The lens must be clear for the retina to get a sharp image. Cataracts cut the amount of light that can reach the retina, the NEI says. This process is a gradual one, progressing so slowly people don't notice much change in their vision. The cataract becomes a problem when the cloudy areas grow large enough to blur or dull vision. Cataracts can also develop when the lens slowly changes color, from clear to yellowish-brown. This type of cataract puts a brown tint on the world, making it more difficult to see blues and purples.

Sometimes the cataract shows up years after the injury, the NEI says. Other causes of cataracts are diabetes, steroid use, surgery for other eye problems, and radiation exposure. Infants can be born with cataracts or develop them in childhood.

Advancing age is the main risk factor for cataracts, but other risk factors in addition to smoking are heavy alcohol use, diabetes, and prolonged exposure to sunlight, the NEI says.

Lights also may seem too bright. Other symptoms include cloudy or blurry vision, faded colors, difficulty seeing at night, double vision, and a frequent need to change the prescription of your eyeglasses or contact lenses, the NEI says. If you have any of these symptoms, talk to your health care provider.

Cataracts don't go away on their own. Although cataracts don't cause vision problems at first, they eventually grow large enough to affect your sight, making driving, reading, or watching television difficult, the NEI says. When this occurs, talk to your health care provider about getting the cataracts removed. Surgery is the only way to treat cataracts; if you have cataracts in both eyes, surgery will be done on each eye separately, with at least four to eight weeks between procedures. According to the American Academy of Ophthalmology, cataracts are the leading cause of blindness worldwide.

This procedure is called phacoemulsification, or phaco for short. The surgeon makes a small cut on the side of the cornea, the clear, dome-shaped surface that covers the front of the eye. He or she inserts a tiny device that emits ultrasound waves, the NEI says. The sound waves break up the old lens, which is removed by suction. An artificial lens called an intraocular lens (IOL) replaces the old lens. The IOL is made of clear plastic. For people who cannot have an IOL, soft contact lenses or high-magnification eyeglasses are an alternative.

This is because the eye needs some time to heal after the surgery. The eye with the new lens also needs time to learn to focus with the other eye, the NEI says. Colors may also seem different after surgery; this is because the old lens may have dulled colors. You may need new eyeglasses or contact lenses after your eye heals. Occasionally, problems may develop after surgery. Possible problems include infection, bleeding, inflammation, and double vision. These problems usually can be successfully treated.

Foods with antioxidant properties are especially important, the NEI says. These foods include green, leafy vegetables, and fruits. Another way to help prevent cataracts is to wear sunglasses that protect against ultraviolet radiation and a hat with a brim when you are in sunlight. If you smoke, stop. You should also have a regular eye exam, particularly if you are 60 or older. Your eye doctor will check for cataracts, as well as other eye conditions such as age-related macular degeneration and glaucoma.