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What Is a Cataract?

A cataract is a cloudy area in the lens of the eye that prevents light from reaching the retina causing vision problems. Most cataracts form naturally as we age due to changes in the protein and fibers in the lens of the eye.


Healthy versus cataract lens


Surgery is the only way to remove cataracts and restore your vision. Cataract surgery is one of the most commonly performed surgical procedures in the U.S. It is also one of the most successful. Over 95 percent of cataract surgeries result in improved vision. However, like any surgery, there can be complications that can be severe or sight threatening. Your chance of developing complications is greater if you have another eye disease or serious medical condition. Complications can usually be successfully treated.

A Closer Look at Cataracts

Did you know that cataract surgery can correct astigmatism with an intraocular lens (IOL) that's implanted in the eye after the cataract is removed?

Types of Cataracts

There are three common types of age-related cataracts, each named according to their location within the eye.

Nuclear Cataracts


Illustration of labeled nuclear cataract


Cataracts that affect the center of the lens are called nuclear cataracts. A nuclear cataract progresses slowly, but in time the nucleus tends to darken, changing from clear to yellow and sometimes brown.

Cortical Cataracts


Illustration of labeled cortical cataract


Cataracts that affect the edges of the lens are called cortical cataracts. They are whitish, wedge-shaped streaks on the outer edge of the cortex. Cortical cataracts progress slowly and as they do the streaks extend to the center of the lens interfering with the light's ability to pass through the center of the lens.

Posterior Subcapsular Cataracts


Illustration of labeled subcapsular cataract


Cataracts that affect the back of the lens are called posterior subcapsular cataracts. This type of cataract is found in the back outer layer of the lens directly in the path of the light. This type often develops more rapidly than the other types.