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What is a Cataract?

A cataract is a problem with the lens of your eye. The lens lets the light into your eye and helps you focus. It is made of water and proteins. When the lens is healthy, the proteins are spread evenly and the lens is clear. With cataracts, the proteins clump together, causing cloudy spots on the lens and turning the lens from clear to slightly yellow or brown. Cataracts make it hard to see clearly and may make colors seem dull.

Cataracts are most common in older adults. You can have a cataract in one eye or both eyes, but cataracts do not spread from one eye to the other.


Cataracts often cause these vision problems:

  • Cloudy or blurry vision
  • Sensitivity to glare from bright lights, like headlights
  • Poor night vision
  • Faded or dull colors
  • Double vision (sometimes)

If your eyeglass prescription needs to be changed a lot, it might mean that you have a cataract.

When to See a Doctor

Whenever you notice a problem with your vision, make an appointment to see your eye doctor. Your symptoms might be from a cataract or other eye problem.


Cataracts usually develop as people get older, and are caused by normal wear and tear on the eyes. Ultraviolet light from the sun can cause cataracts over time. Smoking can also cause cataracts or make them worse. Some diseases, like diabetes, might increase your risk for cataracts.

Diagnosis and Tests

To check for cataracts, your eye doctor will do a full eye exam, which will likely include:

  • Vision exam. This exam checks how well you can see at a different distances.
  • Dilated eye exam. In this exam, the doctor will put drops in your eyes to widen your pupils (the dark spot in the middle of your eye that is actually an opening to let the light in). With the pupil wide open, the doctor can look into the eye and check for problems.
  • Tonometry. This test measures the pressure of the fluid inside your eyes and is used to check for glaucoma, a condition caused by extra fluid in the eye that damage the optic nerve. If you’ve been to the eye doctor, you might remember tonometry as the “puff of air” test, but your doctor may also use a different tonometry test.


  • For a cataract that is small or in the beginning stages, you may only need to change your glasses prescription, get anti-glare glasses, or improve lighting when you read or do close work.
  • Once a cataract is bad enough that these things don’t help, cataract surgery is the only option. In cataract surgery, your eye lens with the cataract is removed and replaced with a new artificial lens.


According to the National Eye Institute, more than half of all Americans have had a cataract by age 80. But you can lower your risk of getting a cataract by doing these things:

  • Protect your eyes from the sun by using sunglasses and a wide-brimmed hat
  • Quit smoking or don’t start
  • Eat a healthy diet with foods like leafy greens that have plenty of good nutrients for your eyes (and prevent diseases like diabetes)

Cataracts are an age-related eye problem. Cataracts develop when the proteins in the lens of the eye clump up and make the lens cloudy. A cataract can make your vision blurry, increase sensitivity to glare and make it hard for you to see at night. At first, cataracts can be treated with anti-glare glasses and a new eyeglass prescription. Once those no longer work, cataracts are treated with surgery that replaces the lens with an artificial one.