Health Topic

Cataract

A cataract is a clouding of the lens in your eye. It affects your vision. Cataracts are very common in older people. Learn about symptoms and surgery.

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Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About Cataract

A cataract is a clouding of the clear lens inside your eye. This cloudiness blocks light from reaching the back of the eye, making it harder to see clearly. A cataract can affect one or both eyes, but it doesn't spread from one eye to the other.

Cataracts usually develop slowly. As they get worse, your vision can become blurry or dim. Brighter lighting or new eyeglasses may help at first, but if cataracts begin to interfere with your daily activities, you may need cataract surgery.

Without treatment, cataracts can cause severe or even permanent loss of vision.

Most cataracts develop as part of the normal aging process. This happens when the protein in the lens of your eye clumps together. Over time, these protein clumps grow larger and thicker, making it harder to see. The lens may turn yellow or brown, which can affect how you see colors.

Cataracts can also develop after an eye injury or surgery for another eye condition, like glaucoma.

Cataracts are very common in older adults. By age 80, more than half of all Americans either have a cataract or have had cataract surgery. Your risk for developing cataracts increases as you get older. You may also be at an increased risk if you:

  • Have certain health problems, like diabetes
  • Have a family history of cataracts
  • Have had an eye injury or eye surgery
  • Take steroid medicines, used to treat conditions like arthritis or allergies
  • Smoke
  • Drink excessive amounts of alcohol
  • Have spent a lot of time in the sun

You may not notice cataracts at first because they usually develop slowly. That's why regular eye exams are important. Common symptoms may include:

  • Blurry or cloudy vision
  • Colors that seem faded
  • Glare from headlights, lamps, or sunlight that seems too bright
  • Halos around lights
  • Not being able to see well at night
  • Double vision (this may go away as the cataract gets bigger)
  • Frequent changes in your glasses or contact lens prescription
  • Trouble reading or doing other everyday activities

Talk with your provider about these symptoms since they could also be signs of other eye problems.

A comprehensive eye exam is the best way to check for cataracts. Your provider will do several tests to check your vision and eye health. This includes a dilated eye exam, where your pupils are widened with special eye drops. This allows more light to enter your eye so your provider can clearly see tissues at the back.

Surgery is the only way to remove a cataract. At first, you may be able to improve your vision with new glasses and brighter lighting. But if cataracts are getting in the way of everyday activities like reading, driving, or watching TV, surgery is an option. During surgery, the cloudy lens is removed and replaced with an artificial lens, called an intraocular lens (IOL).

If you're worried that you're at risk for cataracts, talk to your provider to see if there's anything you can do to lower your risk. A few ways to protect your eyes include:

  • Wear sunglasses and a wide-brimmed hat to block ultraviolet (UV) sunlight and help delay cataracts.
  • Protect your eyes from injury when using power tools or playing certain sports.
  • Eat a healthy diet with plenty of fruits, vegetables, leafy greens, nuts, and whole grains.

It sits within Older Adults and Eyes and Vision.

The lead U.S. institute for this subject is the National Eye Institute.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Cataract

1,960 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

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Diagnosis and Tests

Treatments and Therapies

Related Issues

Genetics

Statistics and Research

Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Cataract. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Cataract, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.