Cataracts

Cataracts

Partly cloudy, with a chance of clearing

A cataract is a clouding of the eye's lens. Cataract surgery is the most common procedure for U.S. Medicare recipients.

Once vision becomes seriously compromised, cataracts are usually treated with surgery. Interestingly, clinical studies suggest that antioxidant supplements can keep cataracts from getting worse and, in some cases, actually improve vision.

Pronunciation

KA-te-rakt

Detailed Description

Normally, the lens of your eye is a transparent, flexible structure near the front of the eyeball. Cataracts are opaque blemishes on the lens caused by protein "tangles." Cataracts block light from passing through the lens and distort the light that is focused on the retina. Signs of a problem include blurred vision, especially in bright light. Cataracts can form in one or both eyes, and are not cancerous.

Some types of cataracts (called mature and hypermature) may cause irreversible damage from swelling and inflammation if they are not removed. Ironically, a cataract in the central part of the lens may actually improve vision at first by essentially making one more nearsighted.

Causes of cataracts include injury to the eye, untreated eye inflammation, diabetes, drugs such as cortisone, exposure to X-rays and ultraviolet (UV) light, and heredity. Exposure to rubella (German measles), before birth may cause congenital cataracts. Although not usually painful, advanced cataracts can cause narrowing of the angle of the eye and increased eye pressure (glaucoma), which can be painful. While cataracts are quite common in the elderly, they are not inevitable.

In advanced cases, surgery is a routine method of treatment, and is even performed on an outpatient basis. Medications aren't usually prescribed, except for right after surgery.

Characteristics of Cataracts

Principal features of cataracts include the following:

  • Cloudiness of the eye lens
  • Blurred vision, especially in bright light
  • Commonly corrected with outpatient surgery

How Common Are Cataracts?

Cataracts are the leading cause of impaired vision and blindness in the United States. The number of people with cataracts increases with age, with 5% of the population between ages 52 and 62 affected, and more than 50% of those over 65. About 46% of people between ages 75 and 85 have significant vision loss, and 92% of this same group have cataract changes. Congenital (from birth) cataracts occur in approximately one out of every 250 newborns. Men and women are equally affected.


Established Causes

Most cataracts have no known cause. Trauma, medications, metabolic disorders such as diabetes, and congenital infections have all been implicated as possible causes.

Theoretical Causes

Environmental factors that may cause cataracts include smoking and lifelong exposure to sunlight, X-rays, microwaves, and infrared radiation.

Risk Factors

Most cataracts have no known cause. However, there are several risk factors for this condition. Of these, age is the primary factor. Other factors:

  • Existing illnesses such as diabetes mellitus, hypoglycemia, and galactosemia
  • Low blood calcium
  • Exposure to sunlight over one's lifetime, X-rays, microwaves, and infrared radiation
  • Eye injury
  • Heredity
  • Prenatal exposure to rubella (German measles)

Risk factors are traits or behaviors that may make you statistically more likely than others in the general population to have a certain condition. They are not necessarily "causes" of the condition.


Symptoms

There are several types of cataracts: age-related, congenital (from birth), secondary, and traumatic. For age-related cataracts, the signs and symptoms include the following:

  • Blurred vision, especially in bright light
  • Double vision
  • Poor night vision
  • Frequent changes in your eyeglass prescription

For congenital cataracts, the main sign is a cloudy lens present at birth or within the first three months of life.

Certain health conditions, such as diabetes, make secondary cataracts more likely. In addition, steroid use has been linked to the condition.

Traumatic cataracts sometimes develop after a blow to the eye, up to years later.

Your own observation of degraded vision is usually the first sign of a cataract. Seeing "halos" or scattering around bright lights should raise suspicion. A doctor's exam should follow these signs.

Conditions That May Be Mistaken for Cataracts

Vision problems can indicate cataracts or they can signal another condition altogether. Your doctor can usually diagnose cataracts using biomicroscopic examination.

How Are Cataracts Diagnosed?

You may want to inform your doctor if you have a history of any of the following:

  • Diabetes mellitus
  • Infections of rubella, herpes, or mumps during the first trimester of pregnancy
  • Eye trauma
  • Taking certain drugs, such as corticosteroids, busulfan, tamoxifen, and allopurinol

Specific Tests

Exams for cataracts usually begin with standard eye tests. These include checking how well your eye works at various distances and dilating your pupil with eye drops (to check the retina). Your eye will then be visually examined for a cataract. Other tests may include the following, particularly if surgery is being considered:

  • Tonometry: a brief, painless burst of air measures the fluid pressure of your eye, used to check for glaucoma
  • Keratometry: measures the cornea's curvature
  • Ocular ultrasonography: uses sound waves to examine the eye

Goals of Treatment

In early stages, cataracts can be treated with new prescription eyeglasses or contact lenses. Medications aren't usually prescribed. Once they seriously interfere with your vision, cataracts can only be cured by surgical removal. The goal of the surgical treatment is to remove the cataract by replacing the lens with an implant.

Treatment Options

If your eye care professional (optometrist or ophthalmologist) discovers a cataract, it may not be serious enough to require treatment. If the cataract is not interfering with your daily activities, you may be encouraged to wait to find out if the cataract grows, meanwhile trying preventive methods.

Surgery

There are three surgical methods, almost always done on an outpatient basis:

  • Extracapsular surgery: The lens is removed except for the back half of its outer covering.
  • Phacoemulsification: Only the lens core is removed after breaking it up with ultrasound.
  • Intracapsular: The entire lens and its capsule are removed. (This is rarely done.)

Most often, a plastic disc is inserted into the eye, replacing the lens. This artificial lens is a permanent implant. If you are not able to tolerate an insert, removable contact lenses or special-purpose eyeglasses are used.

Recovery from the roughly one-hour operation takes only a day or so, but adjusting to the new lens can require weeks for some people, and as much as several months for others. For several weeks after surgery, using eye drops or ointment is recommended to prevent infection, reduce inflammation, and promote healing. Note that cataract surgery can increase the risk of retinal detachment, which may occur at a later date.

Drug Therapy After Cataract Surgery

  • Antibiotics: used for seven to 14 days to prevent intraocular infection (endophthalmitis).

Considerations When Selecting a Treatment

If you're considering surgery, you'll probably know from discussions with your doctor when the time is right. If you feel unsafe, uncomfortable, or unable to perform daily tasks, you may be ready for surgery. The legal requirement for a driver's license in most states is 20/40 vision, so a driver's better eye falling below this level may indicate when to have the cataract removed. A less active person may have a lifestyle that is relatively unaffected by poor eyesight. Before deciding on surgery, you can try other treatment methods. For example, your vision may improve with new eyeglasses or contact lenses.

Monitoring the Condition

Your doctor will closely monitor your vision for several weeks after the operation. To maximize your improved vision after surgery, you will need eyeglasses or contact lenses.

Possible Complications

  • Blindness

Complications following surgery include the following:

  • Eye infections
  • Adhesions
  • Retinal detachment
  • Rupture of the eye
  • Bleeding in the eye

Activity and Diet Recommendations

You should stop driving, at least at night, until the cataract is corrected.

It may help to eat more of the following foods in the early stages of cataract development: yellow, orange and dark-green vegetables; whole grain cereals and breads; and legumes. These contain vitamins known as antioxidants that trap free radicals, which are molecules that cause damage to the body's cells, including those in the eye.

Considerations for Women

Pregnancy

Viral infections during pregnancy-- such as rubella, measles, and mumps-- can cause cataracts in the newborn baby. Talk to your doctor about your infection risk. Also, poor nutrition during pregnancy can cause congenital cataracts.

Considerations for Children and Adolescents

Uveitis is an eye disorder that can affect children; it can cause cataracts and should be treated promptly.

Supplements

  • Take supplemental antioxidants. Like the antioxidants in plant foods, antioxidant supplements have been shown in many studies to help prevent cataracts and to improve vision in those with early cataracts.[1, 2] Vitamins A, C, and E are particularly beneficial.

Herbs

  • Dark berries help prevent cataracts and treat early ones. The beneficial berries include bilberry (also known as European blueberry) and its close botanical relatives: blueberry, cranberry, blackberry, raspberry, and huckleberry. Bilberries have a centuries-old folk reputation in Europe for improving vision. Recent research has discovered that bilberries and other dark-colored berries are rich in anthocyanidins, potent antioxidants that target the eye. Italian researchers gave bilberry extract and vitamin E to 50 people with early-stage cataracts. This treatment kept most of their cataracts from getting worse. [3]

Last updated October 1999.

Sources

1 Jacques, P.F. et al. "Long-Term Vitamin C Supplement Use and Prevalence of Early Age-Related Lens Opacities," Am. J. Clin. Nutrition 66:911, 1997.

2 Seddon, J.M. et al. "Use of Vitamin Supplements and the Risk of Cataract Among US Male Physicians," American Journal of Public Health 84:788, 1994.

3 Bravetti, G. "Preventive Medical Treatment of Senile Cataracts with Vitamin E and Anthocyanosides," Annals Ottamol. Clin. Ocul. 115:109.uvy{9(R)|}, 1989.

 


Preventing Cataracts

The following lifestyle changes can lessen your risk of developing cataracts:

  • Quit smoking.
  • Increase your intake of antioxidants.
  • Wear protective eyewear if your work or hobbies place you at high risk for eye injury.
  • Wear protective glasses if you are a healthcare professional exposed to laser beams or infrared radiation.

Self-Care Measures

Once a cataract has begun to develop, help halt its progression by making the following changes to your lifestyle:

  • Don't smoke. It accelerates oxidative damage -- a likely cause of cataracts -- to the eye. Smokers are considerably more likely than nonsmokers to develop cataracts.
  • Wear sunglasses that block 100% of ultraviolet radiation, since it can worsen cataracts. Also, wear eye protection at work if it is recommended for your job.
  • Eat more fruits and vegetables that are high in antioxidants -- vitamins A, C, E, and selenium -- that help prevent this damage. Many studies have shown these nutrients to be protective. For example, Harvard researchers have tracked the diet and health of 120,000 U.S. women nurses for many years. Those who consumed the most vitamin A and C from foods had the lowest risk of developing cataracts.

Websites & Organizations

American Academy of Ophthalmology
P.O. Box 7424
San Francisco, CA 94120-7424
Phone: 415-561-8500
www.eyenet.org

American Optometric Association
243 Lindbergh Boulevard
St. Louis, MO 63141
Phone: 314-991-4100
Email: AmOptCCC@aol.com
www.aoanet.org

ASCRS-ASOA
4000 Legato Road, Suite 850
Fairfax, VA 22033
Phone: 703-591-2220
Fax: 703-591-0614
Email: ascrs@ascrs.org
www.ascrs.org

Clinical Pearls Archive
Phone: 415-561-8540
Fax: 415-561-8575
Email: clinical_education@aao.org

International Society of Refractive Surgery
www.isrs.org

National Eye Institute
2020 Vision Place
Bethesda, MD 20892-3655
Phone: 301-496-5248
www.nei.nih.gov

Northwest Vision Institute
1370 116th Avenue NE, Suite 110
Bellevue, WA 98004
Phone: 425-450-2020
Fax: 425-688-0620
www.nwvision.com

Prevent Blindness America
500 East Remington Road
Schaumburg, IL 60173
Phone: 800-331-2020 or 847-843-2020
prevent-blindness.org

Steen-Hall Eye Institute
2611 Greenwood Road
Shreveport, Louisiana 71103
Phone: (318) 631-2020 or (800) 326-9938
www.steen-hall.com

Sources for This Article

Books

Balch, James F., and Phyllis A. Balch.Prescription for Nutritional Healing. Garden City Park, NY: Avery Publishing, 1997.

Bennett, J. Claude, and Fred Plum, eds. Cecil Textbook of Medicine. Philadelphia: W. B. Saunders, 1996.

Fauci, Anthony J., et al. , eds. Harrison's Principles of Internal Medicine. New York: McGraw-Hill, 1998.

Hardman, Joel G., and Lee E. Limbird, eds. Goodman and Gilman's The Pharmacological Basis of Therapeutics. New York: McGraw Hill, 1996

Hurst, J. Willis, ed. Medicine for the Practicing Physician. Stamford, CT: Appleton & Lange 1996.

Murray, Michael T. Encyclopedia of Natural Medicine. Prima, 1998.

Noble, John, ed. Primary Care Medicine. St. Louis: Mosby, 1996.

Physicians' Desk Reference. Montvale, NJ: Medical Economics Co., 1998.

Rakel, Robert E., ed. Conn's Current Therapy. Philadelphia: W.B. Saunders, 1998.

Taylor, Robert B. Family Medicine: Principles and Practice. New York: Springer-Verlag, 1998.

Tierney, L.M., S.J. McPhee, and M.A. Papadakis, eds. Current Medical Diagnosis and Treatment. Stamford, CT: Appleton & Lange, 1998.


Articles

Elliott, D.B., M.A. Bullimore, A.E. Patla, and D. Whitaker. "Effect of a Cataract Simulation on Clinical and Real World Vision." British Journal of Ophthalmology, 80(9):799-804. Sep 1996.

Ficker, L. "Cataract: Current Management." Br J Hosp Med., 55(10):607-10. May 15-June 4, 1996.

Freeman, R.S., and L.P. Rovick. "Cloudy Lenses and Issues: A Pedigree of Unoperated Congenital Cataracts." J Ophthalmic Nurs Technol., 14(3):118-23. May-Jun 1995.

Hodge, W.G., J.P. Whitcher, and W. Satariano. "Risk Factors for Age-Related Cataracts." Epidemiol Rev., 17(2):336-46. 1995.

Lee, S.M., S.Y. Lin, M.J. Li, and R.C. Liang. "Possible Mechanism of Exacerbating Cataract Formation in Cataractous Human Lens Capsules Induced by Systemic Hypertension or Glaucoma." Ophthalmic Res., 29(2):83-90. 1997.

Livingston, P.M., C.A. Carson, and H.R. Taylor. "The Epidemiology of Cataract: A Review of the Literature." Ophthalmic Epidemiol., 2(3):151-64. Dec 1995.

Pesudovs, K., and D.J. Coster. "Cataract Surgery Reduces Subjective Visual Disability." Aust N Z J Ophthalmol., 25 Suppl 1():S3-5. May 1997.

Schein, O.D., E.B. Bass, P. Sharkey, R. Luthra, J.M. Tielsch, J.C. Javitt, E.P. Steinberg. "Cataract Surgical Techniques. Preferences and Underlying Beliefs." Arch Ophthalmol., 113(9):1108-12. Sep 1995.

Tavani, A., E. Negri, and C. La Vecchia. "Food and Nutrient Intake and Risk of Cataract." Ann Epidemiol., 6(1):41-6. Jan 1996.

Trudo, E.W. and W. J. Stark. "Cataracts. Lifting the Clouds on an Age-Old Problem." Postgrad Med., 103(5):114-6, 123-6. May 1998.

Jacques, P.F., et al. "Long-Term Vitamin C Supplement Use and Prevalence of Early Age-Related Lens Opacities," Am. J. Clin. Nutrition., 66:911, 1997.

Seddon, J.M., et al. "Use of Vitamin Supplements and the Risk of Cataract Among US Male Physicians," American Journal of Public Health, 84:788, 1994.

Bravetti, G. "Preventive Medical Treatment of Senile Cataracts with Vitamin E and Anthocyanosides," Annals Ottamol. Clin. Ocul., 115:109.uvy{9(R)|}, 1989.

 

 

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