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A B C D E F G H I J K LM N O P Q R S T U V W X Y Z 0-9
(A-Z listing includes diseases, conditions, tests and procedures)


Cataracts: What You Need to Know

Eye with cataract
  • A cataract is the clouding of the normally clear lens that sits in the eye behind the pupil.

  • Most cataracts are related to aging. More than half of all Americans have had a cataract or cataract surgery by age 80.

  • Babies, young children and middle-aged adults can also have cataracts, either present at birth or sometimes related to other medical conditions.

  • Common symptoms from cataracts include halos around lights, needing more light to read, reduced clarity of vision and reduction in the brightness of colors. Such symptoms can also be associated with many other eye conditions, so it is important to visit your eye care provider to properly diagnose the cause of your symptoms.

  • Cataract removal is one of the most commonly performed operations in the United States.

Cataract Definition

A cataract is a clouding of the lens of the eye, an area that is normally clear. The lens works much like a camera lens, focusing light onto the retina, where an image is recorded. As we age, proteins that make up the lens can break down and clump together, creating a cloudiness that affects the clarity of vision. A clouded lens is a cataract.

In its early stages, a cataract often has little effect on vision. However, the cataract may grow less transparent over time, increasing the cloudiness of the lens and making it harder to see.

Types of Cataracts

  • Age-related cataracts. The majority of cataracts are related to aging.

  • Congenital cataracts. Babies can be born with cataracts or develop them in childhood. Not all congenital cataracts affect vision, though those that do are usually removed soon after diagnosis.

  • Secondary cataracts. Secondary cataracts occur as a result of inherited genetic disorders, other eye conditions and other medical conditions, such as diabetes.

  • Traumatic cataracts. Past eye trauma or surgeries can result in cataracts, which can occur immediately or years later.

Symptoms of Cataracts

The most common symptoms of cataracts are:

  • Cloudy or blurry vision

  • Faded colors

  • Frequent changes in glasses or contact lens prescriptions

  • Increased glare or halo effect

  • Poor night vision

  • Sensitivity to light

  • Seeing double or multiple images in one eye

Risk Factors for Cataracts

Though experts are not certain what definitively causes cataracts, they have identified factors that can increase your risk of developing them:

  • Age

  • Diabetes

  • Excessive alcohol consumption

  • Excessive exposure to sunlight

  • Family history of cataracts

  • Previous eye condition, inflammation, trauma or surgery

  • Prolonged use of steroids

  • Smoking

Cataracts tend to develop slowly, with symptoms and vision worsening over time. Cataracts usually develop in both eyes and can affect each eye differently.

Diagnosis of Cataracts

In addition to a complete medical history and eye exam, tests to diagnose cataracts may include:

  • Light and magnification (slit-lamp test). A microscope uses a thin, powerful slit of light to examine and identify abnormalities in the front structures of your eye, such as the cornea, iris and lens.

  • Pupil dilation (retinal examination). The pupil is widened with eye drops to allow a close-up examination of the retina and optic nerve.

  • Eye chart reading (visual acuity test). The common eye chart test measures vision ability at various distances.

In addition, other tests may be done to help your eye care professional learn more about the health and structure of your eye.

Treatment for Cataracts

In its early stages, the loss of vision due to cataracts can usually be managed by updating the eyeglass prescription and providing stronger lighting for reading. A cataract only needs to be removed when loss of eyesight gets in the way of your everyday activities, such as driving, reading or watching TV. You and your eye doctor can make that decision together.

Cataract surgery is one of the most common, safe and effective surgeries. It is conducted as an outpatient procedure. Surgery involves swapping out the cloudy lens with an artificial lens, called an intraocular lens, or IOL. The IOL becomes a permanent part of the eye, and you cannot see or feel it. The IOL allows light to pass through to the retina, restoring clarity of vision.

  • The most common form of cataract surgery, often called small-incision cataract surgery (phacoemulsification), involves a small incision on the side of the cornea, which is the clear, dome-shaped surface that covers the front of the eye. A tiny probe emits ultrasound waves to soften and break up the cloudy lens. It is then suctioned out of the same incision. The IOL is then inserted through the same incision.

Complications of Cataract Surgery

Complications of cataract surgery that affect vision occur on the order of one in 100 surgeries. There are certain conditions that increase the risk of cataract surgery, such as the presence of diabetic changes in the eye, very dense cataracts, pupils that cannot be adequately dilated, and other conditions that your cataract surgeon can identify and discuss with you, if pertinent.

Sometimes after cataract surgery, the eye behind the new lens can become cloudy. This is an after-cataract. An after-cataract can appear months or even years after cataract surgery. Unlike a cataract, an after-cataract can be treated with a laser that makes a tiny hole in the eye tissue behind the lens, allowing light to pass through. This is an outpatient procedure called a YAG capsulotomy, which is painless and is typically performed during a routine office appointment. Full recovery for the eye can be as little as a few days but often takes up to a month.

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