Types

What Are Cataracts?

Choose a preferred language

The lens in the eye focuses light so the eye sees images sharply. Aging is the most common cause of cataracts. With age, the lens slowly becomes cloudy. The cloudy lens is a cataract. A cataract scatters light and makes it hard for the eye to focus. Cataracts usually form in both eyes. But one lens may cloud faster than the other.

Three-quarter view of eye showing lens sharply focusing light. Three-quarter view of eye showing cataract scattering light.


The aging of your lens

Your lens may cloud so slowly that you don`t notice any vision changes at first. But as the cataract gets worse, the eye has a harder time focusing. In early stages, glasses may help you see better. As the lens gets more cloudy, your healthcare provider may advise surgery to restore your vision.

A clear lens allows your eye to bring objects sharply into focus.

A mild cataract may slightly blur your vision.

A dense cataract can severely blur your vision.

Online Medical Reviewer: Chris Haupert MD

Online Medical Reviewer: Marianne Fraser MSN RN

Online Medical Reviewer: Raymond Kent Turley BSN MSN RN

Date Last Reviewed: 09/01/2025

© 2000-2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
Related Articles
Read article
Eye Care
Foreign Object in the Cornea

A foreign object can get into the cornea. A trapped speck of dirt or grit is often a minor problem. But anything metal, or an object that goes through (pierces) your cornea, can cause severe damage. Here's what you need to know about getting emergency medical care.

Read article
Eye Care
Conjunctivitis Caused by Infection

Infections are caused by viruses or germs (bacteria). Treatment includes keeping your eyes and hands clean. Your health care provider may prescribe eye drops. They may also tell you to stay home from work or school if you're contagious.

Read article
Eye Care
Acquired Brown Syndrome (Superior Oblique Tendon Sheath Syndrome)

Brown syndrome is a problem with a tendon that attaches to the eyeball. In Brown syndrome, this tendon can’t move freely. This limits the eye’s normal movement. Brown syndrome is a rare disorder. It is usually present at birth (congenital). In some cases, it occurs later in life (acquired).

Read article
Eye Care
Eye Injury (Black Eye)

Detailed information on ecchymosis or bruising of the eye