Cataracts

Cataracts are the number one cause of poor vision among older adults. Over two-thirds of people over age 60 will have a vision problem due to cataracts.

What is a cataract?
A cataract is a clouding of the eye's natural lens. Located behind the iris and the pupil of the eye, the lens focuses light on the retina in the back of the eye, which in turn allows you to see. The lens of the eye is similar to the lens of a camera. When the camera lens is not working properly you get a blurry photograph. When the lens of the eye becomes cloudy your vision decreases and things appear blurry.

What causes cataracts?
It is thought that most cataracts occur due to the natural aging of the body. However, other factors can be involved. Some diseases, such as diabetes or glaucoma, or the use of certain medications, such as steroids, are thought to increase the chance of a cataract occurring. Physical and chemical injury to the eye and exposure to intense heat or radiation are also associated with cataract development.

Who can have a cataract?
Basically cataracts can occur at any age. However, most cataracts occur in people who are 60 years of age or older, although a smaller number of people develop cataracts between the ages of 45 and 60. Sometimes cataracts occur in children at birth due to genetic disorders or if the mother had rubella (German measles). Cataracts due to injury can occur at any age.

What are some cataract symptoms?
Depending on the nature and cause, a cataract can develop rapidly over a few months or slowly over many years. In older people, it is not unusual for cataracts to develop in both eyes but most of the time the cataract develops in only one eye at a time. As the cataract progresses, most people notice that it is more difficult to see things clearly from a distance.

As a result of the cataract, some people find that they no longer need to use their bifocals or glasses to read. However, this effect is only temporary and as the cataract gets worse it will again be difficult to see close up. Other people with cataracts experience problems with glare, especially at night, or notice that colors appear dull and faded. People with a cataract in only one eye may notice a loss of depth perception. This can cause problems in judging where stairs are and determining the distance of cars driving in front of them.

How are cataracts treated?
At this time, there is no medication to cure or prevent cataracts. The only way to remove the cataract is through surgery. Cataract surgery is one of the safest and most common types of eye surgery. Over one million people have cataract surgery every year. Most often, cataract surgery does not require hospitalization and the patient goes home from the hospital the same day the surgery is performed.

Can cataracts be removed with lasers?
Due to misinformation on television or in newspapers and magazines, many people have been led to believe that cataracts can be removed with lasers. At this time, cataracts can NOT be removed with lasers and can only be removed by surgery. Sometimes, AFTER cataract surgery, a membrane near where the cataract was removed becomes cloudy. This membrane is called the lens capsule. In order to regain vision, the lens capsule must be cut, and this procedure may be done with a laser.

Can the cataract "grow back"?
Once a cataract is removed, it is not possible for it to grow back. However, the lens capsule may become cloudy, making it seem as if the cataract is growing back. In fact, the clouding of this membrane has sometimes falsely been called a "second cataract." However, an opthamologist can cut the membrane, often with a laser, to restore vision to the level attained after the cataract surgery.

How is vision corrected after the cataract is removed and what is a lens implant?
Cataract surgery is similar to taking the lens out of a camera and a substitute for the lens power is needed in order to obtain the best vision. Lens power replacement can be accomplished through the use of cataract glasses a contact lens, or an intraocular lens implant (IOL).

Most patients receive an IOL that is placed inside the eye close to the original position of the natural lens during the time of cataract removal. An IOL can provide the best vision correction and involves no special care on the part of the patient. However, not all patients are able to have IOL's. Patients who are extremely near-sighted or who have certain eye diseases may have to use contact lens or glasses instead.

When should the cataract be removed?
At one time, doctors did not remove cataracts until they were "ripe." By that time, the patient generally was suffering from extremely poor vision. However, due to improved surgical techniques and the invention of the contact lens and intraocular lens to correct vision after surgery, this is no longer the case.

Today, for the most part, it is up to the patient to decide when they want to have their cataract removed. This is very much an individual decision because each patient has different vision requirments. Generally, patients are advised to wait until their vision is poor enough that it interferes with their normal daily activities. Questions concerning cataracts and the need for cataract surgery should be discussed with your ophthalmologist (a physician who specializes in eye disease and eye surgery).

What should you do if you think you have a cataract?
All people, especially older individuals, should be examined by an ophthalmologist on a regular basis, even if no vision problem is occurring. Some serious eye problems, such as glaucoma, can occur without any physical signs.

If you are having any vision problems, you should visit an ophthalmologist soon. Cataracts are not the only type of eye problem that can cause decreased vision. Some eye problems need to be treated as soon as they are detected in order to prevent blindness. Fortunately, under an ophthalmologist's care, cataracts-which are one of the major causes of vision loss can be successfully treated.

David A. Severance, MD
Family Physician, Lincoln Avenue Clinic

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.