What is a cataract?

A cataract is essentially a cloudy layer that forms on the lens of the eye. Cataracts develop gradually over time, and they ultimately affect a person's ability to see. Eventually, people may need surgery to remove a cataract in order improve their vision.

Picture of cataract
Johns Hopkins Medicine
Administration

Cataracts are cloudy areas in the eye's lens. The lens is the normally transparent structure within the eye that focuses images on the light-sensitive retina. This clouding means your eye can't see those images clearly. If the clouding of the lens continues untreated, it can lead to significant loss of vision and even blindness. Fortunately, the treatment is a very common outpatient surgical procedure.

A cataract is a clouding of the eye’s naturally clear lens, like a window that is fogged with steam. When the lens becomes cloudy, light rays cannot pass through it easily and vision becomes blurred.
Protecting your eyes from sunlight may slow the progression of cataracts. There are no medications, eyedrops, exercises or eyeglasses that will cause cataracts to disappear once they have formed. Surgery is the only way to remove a cataract.
Common symptoms of cataract include:
  • A painless blurring of vision;
  • Glare, or light sensitivity;
  • Poor night vision;
  • Double vision in one eye;
  • Needing brighter light to read;
  • Fading or yellowing of colors.
It is up to you to decide when to have a cataract removed. When you are unable to see well enough to do the things you like or need to do, you should consider cataract surgery.
In cataract surgery, the cloudy lens is removed through a small surgical incision. In most cases, the focusing power of the natural lens is restored by replacing it with a permanent intraocular lens (IOL) implant.
Cataract surgery improves vision in most cases. Cataract surgery is usually done on an outpatient basis so you can go home the same day.
Donna Hill Howes, RN
Family Medicine
Cataract is a condition in which the lens of the eye becomes cloudy. Symptoms include blurred, cloudy, or double vision; sensitivity to light; and difficulty seeing at night. Without treatment, cataracts can cause blindness. There are many different types and causes of cataracts. They may occur in people of all ages, but are most common in the elderly.
Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
Cataracts are the Number 1 cause of blindness in the world. Learn more about cataracts in this video of Dr. Oz.


A cataract is a cloudy structure that forms in the lens of the eye. Watch this video to learn more from Dr. Manvi Maker about cataracts.
Emilia Klapp
Nutrition & Dietetics
Cataracts are cloudy crystals on the lens of the eye. This happens to a lot of people as they age; cataracts also are common in people with diabetes. The cloudy crystals in the eye are caused in part by oxidation and by the formation of advanced glycated end products, also known as AGEs. AGEs are the result of glucose combining with protein. Cataracts are thought to develop from oxidation resulting from the lens’ exposure to the sun. Studies show that people who don’t eat enough fruits and vegetables have a higher risk of developing cataracts. The antioxidants, vitamin C, and folic acid in fruits and vegetables are all preventative measures.
Laura C. Fine, MD
Ophthalmology
A cataract is a clouding of the normally clear lens of the eye (focuses light rays to the retina, the innermost layer of the eye, where images are captured and recorded). The term was apparently coined because the resulting whiteness of the lens resembles the churned-up water of a cataract, or large waterfall. It generally takes years for the lens to become foggy, but the opacity can eventually cause a disabling loss of vision, either by distorting light rays or keeping them from reaching the retina at all.

Most people develop some degree of lens opacity by age 60. Cataracts occur in about half of all people ages 65 to 74 and in about 70% of those older. Despite surgical advances, the lack of access to health care in developing countries makes cataract the leading preventable cause of blindness in the world today.
Dr. Michael Roizen, MD
Internal Medicine
If you boil a pot of pasta by the kitchen window, the window is going to steam up so you can't see out of it. That's essentially what cataracts do: cloud the lens of your eye to cause blurry vision.

Though cataracts don't really cause a total loss of vision, the clouding can worsen over time to the point of making you legally blind (you're legally blind if you can't read the top letter E on a vision chart from a distance of 20 feet).

Many things, including UV light, cigarette smoke, and extra glucose in diabetics (all factors that accelerate arterial aging, by the way), can increase the risk of cataracts. In addition to avoiding these risk factors, getting adequate vitamin C may be helpful in protecting against cataracts.

Cataract surgery can remove the cataract and implant a new lens in the eye.
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Michael T. Murray, ND
Naturopathic Medicine

Cataracts are white, opaque blemishes on the normally transparent lens of the eye. They occur as a result of free-radical or oxidative damage to the protein structure of the lens, similar to the damage that occurs to the protein of egg whites when eggs are heated. Cataracts are the leading cause of impaired vision and blindness in the U.S.

Clouding or opacity in the crystalline lens of the eye occurs in a progressive manner, causing a gradual loss of vision.

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A cataract is caused by a clouding of the lens inside of the eye, which usually occurs as people age.
RealAge
Administration

Just like tree sap you can't get off your car's windshield, a cataract is a milky-colored protein buildup on the lens of the eye. More than half of people will have cataracts by age 80. They can seriously affect vision, but, fortunately, surgery easily removes them in most cases.

Scripps Health
Administration
Cataracts are common after age 60. As eyes age, the lenses become less flexible, thicker and clouded. Symptoms can include blurred or dim vision, sensitivity to glare and seeing halos around lights.
UCLA Health
Administration

Cataracts are a disease in which the eye’s clear lens becomes clouded, requiring surgical removal. Cataracts mainly affect people older than 60.

Continue Learning about Cataracts

Cataracts

Cloudy vision, foggy vision - that's how people describe cataracts. A cataract is a clouding of the eye's lens that happens so gradually you may not really notice it until you have trouble driving at night or difficulty reading. A...

t that point, you may need cataract surgery - a standard procedure that is very effective.
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.