The top lens is clear. The bottom lens shows clouding by cataract.

• What are the symptoms of cataracts?
• Who is at risk for cataracts?
• What causes cataracts?
• How are cataracts diagnosed?
• How are cataracts treated?
• IOL implants
• Additional resources

What are cataracts?
If your vision has become cloudy or things you see are not as bright as they used to be, a cataract may have developed in one or both of your eyes. A cataract is a clouding of the eye’s naturally clear lens. Your eye becomes like a window that is frosted or yellowed.

The amount and pattern of cloudiness within the lens can vary. If the cloudiness is not near the center of the lens, you may not be aware that a cataract is present.

There are many misconceptions about cataract. A cataract is not:

• A growth or film over the eye;
• A cause of irreversible blindness;
• A result of overusing the eyes;
• A contagious disease spread from eye to eye or person to person.

Cataracts are a common cause of vision loss, especially as we age, but they are treatable. Your ophthalmologist (Eye M.D.) can tell you whether cataract or some other problem is the cause of your vision loss and can help you decide if cataract surgery is appropriate for you.

Last reviewed and updated in March 2010,
by the American Academy of Ophthalmology.