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.

Find a Provider

View Our Directory

Find a Location

View Our Practices
Related Articles
Read article
Eye Care
Brown Syndrome in Children

Brown syndrome is a rare disorder that limits the eye's normal movements. Here's what you need to know.

Read article
Eye Care
Iritis

Iritis is the inflammation of your iris and the anterior chamber of your eye. Iritis can lead to serious problems. It can cause severe vision loss and even blindness.

Read article
Eye Care
What Is Presbyopia?

Presbyopia is the loss of close-up focusing. With age, the lens in the eye hardens and can't change its shape as easily. It then can't focus clearly on close objects. This makes them look blurry.

Read article
Eye Care
Convergence insufficiency

Convergence insufficiency (CI) is a problem with the way the eye moves. It makes it hard to focus on things nearby. When the eyes converge, it means they point inward (toward the midline) to focus on something close. With CI, the eyes have trouble doing this. One eye may turn out instead of looking inward. CI can cause blurred vision, double vision, and eyestrain.