Cataract

Answer 1

Definition

A cataract is a cloudy area in the lens of the eye.

This article focuses on cataracts in adults. For information on cataracts in children, see: Congenital cataracts

Alternative Names

Lens opacity

Causes, incidence, and risk factors

The lens of the eye is normally clear. If the lens becomes cloudy, the condition is known as a cataract. Rarely, cataracts may be present at or shortly after birth. These are called congenital cataracts.

Adult cataracts usually develop very gradually with advancing age and may run in families. They develop slowly and painlessly, and vision in the affected eye or eyes slowly gets worse.

Cataracts develop more quickly if there are some environmental factors, such as smoking, exposure to other toxic substances, and exposure to excessive ultraviolet light or sunlight. They may develop at any time after an eye injury. Diseases such as diabetes also greatly increase the risk for cataracts. Certain medications, such as cortisone, can also speed up cataract formation.

Adult cataracts are classified as immature, mature, and hypermature.

• Immature cataract -- lens has some remaining clear areas
• Mature cataract -- completely cloudy, or opaque lens, which means you can't see through it
• Hypermature cataract -- lens tissues are breaking down and leaking through the surface covering, which can damage other structures in the eye

Most people develop some mild clouding of the lens after age 60. About 50% of people ages 65-74, and about 70% of those 75 and older have cataracts that affect their vision.

Factors that may contribute to cataract development are:

• Diseases that cause inflammation or affect metabolism
• Eye injury
• Family history
• Long-term use of corticosteroids or certain other medications
• Radiation exposure
• Smoking
• Too much exposure to ultraviolet light (sunlight)

In many cases, the cause of cataract is unknown.

Symptoms

Visual problemsmay include the following changes:

• Cloudy, fuzzy, foggy, or filmy vision
• Loss of color intensity
• Double vision
• Difficulty seeing at night
• Problems seeing shapes against a background or the difference between shades of colors
• Seeing halos around lights
• Being sensitive to glare

Cataracts generally lead to decreased vision, even in daylight. Most people with cataracts have similar changes in both eyes, although one eye may be worse than the other. Many people with this condition have only mild vision changes.

Other symptoms may include:

• Frequent changes in eyeglass prescription

Signs and tests

A standard eye exam and slit lamp examination are used to diagnose cataracts. Other diagnostic tests are rarely needed.

Treatment

The only treatment for cataract is surgery to remove it. Surgery is done if you cannot perform normal activities, even with glasses.

If a cataract is not bothersome, then surgery is usually not necessary. However, some people may have additional eye problems, such as diabetic retinopathy, that cannot be treated without first having cataract surgery.

For some people, changing glasses, getting stronger bifocals, or using a magnifying lens is helpful enough.

For information on surgery, see: Cataract surgery

Expectations (prognosis)

Vision may not improve to 20/20 after cataract surgery if other eye diseases, such as macular degeneration, are present. Ophthalmologists can usually, but not always, determine this in advance.

Complications

Early diagnosis and treatment are key to preventing permanent vision problems.

Calling your health care provider

Call for an appointment with your health care provider if you have vision loss, decreased night vision, or problems with glare.

Prevention

The best prevention involves controlling diseases that increase the risk of a cataract, and avoiding exposure to factors known to promote cataract formation.

Wearing sunglasses when you are outside during the day can reduce the amount of UV light your eyes are exposed to. Some sunglasses do not filter out the harmful UV. An optician should be able to tell you which sunglasses filter out the most UV. For patients who smoke cigarettes, quitting will decrease the risk of cataracts.

References

American Academy of Ophthalmology Preferred Practice Pattern: Cataract in the Adult Eye.

Olitsky SE, Hug D, Smith LP. Abnormalities of the Lens. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap. 627.

Answer 2

Cataracts may develop with advancing age or in response to diseases such as Diabetes. A cataract appears as a cloudy area in the lens.

Reviewed By

Review Date: 09/16/2011

Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

Answer 3

Definition

A cataract is a clouding of the lens of the eye.

This article focuses on cataracts in adults. For information on cataracts in children, see: Congenital cataracts

Alternative Names

Lens opacity; Age-related cataract

Causes, incidence, and risk factors

The lens of the eye is normally clear. It acts like the lens on a camera, focusing light as it passes to the back of the eye.

Until a person is around age 45, the shape of the lens is able to change. This allows the lens to focus on an object, whether it is close or far away.

As we age, proteins in the lens begin to break down and the lens becomes cloudy. What the eye sees may appear blurry. This condition is known as a cataract.

Factors that may speed up cataract formation are:

• Diabetes
• Eye inflammation
• Eye injury
• Family history of cataracts
• Long-term use of corticosteroids (taken by mouth) or certain other medications
• Radiation exposure
• Smoking
• Surgery for another eye problem
• Too much exposure to ultraviolet light (sunlight)

In many cases, the cause of cataract is unknown.

Symptoms

Adult cataracts develop slowly and painlessly. Vision in the affected eye or eyes slowly gets worse.

• Mild clouding of the lens often occurs after age 60, but it may not cause any vision problems.
• By age 75, most people have cataracts that affect their vision.

Visual problemsmay include the following changes:

• Being sensitive to glare
• Cloudy, fuzzy, foggy, or filmy vision
• Difficulty seeing at night or in dim light
• Double vision
• Loss of color intensity
• Problems seeing shapes against a background or the difference between shades of colors
• Seeing halos around lights

Cataracts generally lead to decreased vision, even in daylight. Most people with cataracts have similar changes in both eyes, although one eye may be worse than the other. Many people with this condition have only mild vision changes.

Other symptoms may include:

• Frequent changes in eyeglass prescription

Signs and tests

A standard eye exam and slit-lamp examination are used to diagnose cataracts. Other diagnostic tests are rarely needed, except to rule out other possible causes of poor vision.

Treatment

The following may help people who have an early cataract:

• Better eyeglasses
• Better lighting
• Magnifying lenses
• Sunglasses

As vision gets worse, you may need to make changes around the home to avoid falls and injuries.

The only treatment for a cataract is surgery to remove it. Surgery is done if you cannot perform normal activities, such as driving, reading, or looking at computer or video screens, even with glasses.

If a cataract is not bothersome, surgery is usually not necessary. Cataracts usually do not harm your eye, so you can have surgery when it is convenient for you.

However, some people may have additional eye problems, such as diabetic retinopathy, that cannot be treated without first having cataract surgery.

For information on surgery, see: Cataract surgery

Expectations (prognosis)

Vision may not improve to 20/20 after cataract surgery if other eye diseases, such as macular degeneration, are present. Ophthalmologists can usually, but not always, determine this in advance.

Complications

Early diagnosis and treatment are key to preventing permanent vision problems.

Although rare, a cataract that goes on to an advanced stage (called a hypermature cataract) can begin to leak into other parts of the eye. This may cause a painful form of glaucoma and inflammation inside the eye.

Calling your health care provider

Call for an appointment with your health care provider if you have:

• Decreased night vision
• Problems with glare
• Vision loss

Prevention

The best prevention involves controlling diseases that increase the risk of a cataract, and avoiding exposure to factors known to promote cataract formation.

Wearing sunglasses when you are outside during the day can reduce the amount of ultraviolet (UV) light your eyes are exposed to. Some sunglasses do not filter out the harmful UV. An optician should be able to tell you which sunglasses filter out the most UV. For patients who smoke cigarettes, quitting will decrease the risk of cataracts.

References

Zigler JS Jr, Datiles MB III. Pathogenesis of cataracts. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 15th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2011:chap 72B.

Howes FW. Indications for lens surgery/indications for application of different lens surgery techniques. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2008:chap 5.4.

Reviewed By

Review Date: 09/16/2011

Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.