|Myth: A cataract is a film over the eye.|
Fact: A cataract is the clouding of the normally clear lens of the eye.
|Myth: A cataract can be caused by overuse of the eye.|
Fact: Severe eye injuries can cause cataracts, but overuse cannot.
|Myth: Cataracts have to be “ripe,” or fully developed, before they can be removed.|
Fact: Cataract surgery can be performed any time your vision requires it.
The word cataract comes from the Latin word for waterfall, and trying to see through a waterfall is a fairly accurate description of what attempting to see with a cataract is like. A cataract is a clouding of the normally clear lens of the eye. It can block out light and impair normal sight. Most cataracts are a natural consequence of aging. In fact, nearly half of all people between the ages of 65 and 74, and 70 percent of those over 75, have cataracts. But only a small percentage will experience a decrease in vision that will require surgery.
Although advancing age is the most common cause of cataracts, other possible factors include:
- Family history
- Long-term, unprotected exposure to sunlight (sunglasses that screen out ultraviolet (UV) light rays and regular eyeglasses with a clear, anti-UV coating offer protection)
- Previous eye surgery
- A chronic medical problem, such as diabetes
- Injury to the eye, especially wounds that penetrate the eyeball
- Some medications, including corticosteroids (used to treat severe allergies and arthritis)
A thorough eye exam by your eye doctor can detect the presence and determine the extent of a cataract. If you are experiencing any of the symptoms listed below, see your doctor. These symptoms could indicate a cataract or some other eye problem, but only your eye doctor can tell for sure.
- Cloudy, fuzzy, foggy or filmy vision without pain
- Colors look washed out
- Problems driving at night because headlights seem too bright
- Glare from lamps or the sun
- A frequent change (every year) in your eyeglass prescription
- Double vision
- A short-term improvement of near vision in farsighted people
- Needing brighter light to read
- Change in the color of the normally black pupil (the round center of your eye through which light enters) to a cloudy white
- Difficulty performing daily tasks due to problems with vision
|Normal Vision. The lens is the small oval structure located in the front of your eye just behind the pupil. The lens catches light and focuses it at the back of your retina where vision occurs. The retina then sends a vision message to your brain through the optic nerve.|
|Vision With a Cataract. When the lens is clouded by a cataract, a clear message cannot reach your retina.|
To determine whether you have a cataract, your eye doctor will begin by conducting a regular eye exam. First, he or she will ask you to read a letter chart in order to evaluate your sight. Your doctor will then examine the inside of your eyes with a bright light to check whether your lenses are clear and whether there are any other problems in the back of your eye. He or she may give you eye drops that enlarge your pupils to get a better look at the inside of your eyes. In some cases, additional tests may be needed to see how severe the cataract is and whether surgery is indicated.
Once a cataract is diagnosed, there is no way to tell how quickly it will develop. That varies from person to person and may even vary between two eyes. Most cataracts associated with the aging process progress gradually over a period of years.
Depending on the rate of development, a stronger eyeglass prescription or a magnifying lens may help improve your vision and be treatment enough. Surgery, however, is the only way to remove a cataract. Contrary to popular belief, drugs, eye drops, dietary supplements, eye exercises and lasers (instruments that produce a thin beam of light strong enough to destroy tissue) cannot effectively treat or prevent a clouded lens. Cataract surgery should be considered only when loss of vision interferes with daily activities. Although the surgery almost always improves sight, as with any surgery, it does carry with it a slight risk of complications, which can threaten vision or require further surgery.
Additionally, as with a cataract’s progression, the amount that vision improves after surgery varies with the individual. Ask your doctor what you can expect. He or she can make an assessment taking the following factors into consideration:
- How well could you see in the past?
- Do you have a healthy retina (a light-sensitive layer of the eye that receives and transmits visual information) and optic nerve?
- Is your eye healthy in most other regards?
- Is your other eye healthy?
More than 1.4 million Americans have cataract surgery each year, making it the leading surgical procedure for people over 65. Most often, cataract surgery does not even require an overnight hospital stay. It can be performed under local anesthesia by an ophthalmologist (a medical doctor who can prescribe medication and perform eye surgery) on an outpatient basis in an outpatient center or hospital. The surgery itself takes less than an hour. If your eye doctor is not licensed to perform surgery, he or she can refer you to someone who is. Click here for some questions to help you decide it surgery is right for you.
There are two stages to cataract surgery. The first consists of removing the lens, the second of replacing it.
Step I: Removing the Lens
The clouded lens can be removed in one of three ways:
1) Extracapsular surgery. This is the most common cataract removal method. A small incision is made at the outer edge of the cornea, the transparent outer layer of the eye, and the front of the lens capsule is removed together with the lens, leaving the rest of the capsule in place.
2) Phacoemulsification (phaco = lens, emulsification = liquefy). The doctor softens the lens using sound waves and suctions it out through a tiny opening with a finely regulated aspirator. As in extracapsular surgery, the back half of the lens capsule is left in place. Increasingly, eye surgeons are switching to this method of lens removal, which leaves the eye less traumatized than traditional surgery, allowing it to heal more quickly. However, there are cases in which phacoemulsification cannot be performed, for example, if the cataract is extremely dense or the lens is dislocated.
3) Intracapsular surgery. The surgeon removes the entire lens, including the capsule. Although this procedure was once very common, it is now rarely used–generally when the lens has broken loose or into pieces and the capsule cannot be saved.
Step II: Replacing the Natural Lens
Once the clouded lens is removed, light can once again freely enter your eye, but your eye cannot focus it without a lens. There are three ways in which the removed lens can be replaced:
1) Intraocular lenses. Today, the most common way to restore vision after a cataract is removed is by implanting a permanent plastic lens called an intraocular lens, or IOL, in its place at the time of lens removal surgery. Past veterans of intracapsular surgery can now often be fitted with an IOL through what is known as a secondary implant. The lens is supported by the edge of the iris, the circular, colored part of the eye surrounding the pupil, instead of the capsule. Of the three types of replacement lenses available, an IOL simulates natural vision most closely. It provides full peripheral vision and good depth perception. However, reading glasses are required for optimal vision. According to the American Academy of Ophthalmology, the most effective and safest IOL is the posterior-chamber IOL.
2) Cataract glasses. Before the advent of IOLs, these were used to restore vision following cataract surgery. Cataract glasses have very thick lenses which enlarge objects 30 to 35 percent. But peripheral vision is restricted and distant objects appear distorted. These days, cataract glasses are prescribed very rarely–only when there aren’t any structures in the eye strong enough to support an IOL.
3) Contact lenses. Cataract contact lenses provide far superior vision to cataract glasses. They offer more peripheral vision and less distortion of distant objects. But they can be difficult to insert and remove, and not everyone can wear them. Patients who opt for contact lenses must get reading glasses as well because contact lenses do not provide enough magnification for reading. Contact lenses, too, are recommended only when an IOL cannot be implanted.
Ask a friend or family member to escort you home after the surgery. Your ophthalmologist will see you the day after surgery and will schedule three follow-up visits in the next six to eight weeks to monitor your progress. Avoid strenuous physical activities until the eye has healed–usually between three and five weeks–and protect your eye from possible injury and foreign objects by wearing eye-glasses or a shield, as advised by your doctor. Normal daily activities, such as light housework, bathing and shopping, and moderate exercise like walking or stretching are fine. Ask your doctor when you can begin driving again.
Although 95 percent of cataract surgeries go off without a hitch, post-operative problems, like infection, bleeding and swelling, or detachment of the retina, can occur. Call your ophthalmologist immediately if you experience any of the following symptoms: Pain not relieved by non-prescription pain medication; loss of vision; nausea, vomiting or excessive coughing; injury to the eye.
No. Because all or part of the affected lens has been removed. The misconception that a cataract can return may be related to what is commonly referred to as a secondary cataract. In about half of all people who have extracapsular surgery or phacoemulsification, the natural capsule that supports the intraocular lens becomes cloudy several months or years after the original cataract operation as a result of the body’s unsuccessful attempt to grow a new lens.
If a secondary cataract does develop, a laser can be used to restore clear vision. This procedure, called YAG capsulotomy, is painless and can be performed on an outpatient basis.
Medical advances continue to make the treatment of cataracts easier, yielding better results. Although cataracts may be an inevitable fact of life for many people as they age, the vision loss associated with this condition doesn’t have to be.
Our thanks to Denis O’Day, M.D., Chairman of the Department of Ophthalmology and Visual Sciences, Vanderbilt University, Nashville, TN, for reviewing this article.
The following list, excerpted from guidelines published by the U.S. Department of Health and Human Services’ Agency for Health Care Policy and Research, can help you and your doctor determine whether cataract surgery is necessary. Check the statements that apply and share the list with your doctor.
- I need to drive, but there is too much glare from the sun or headlights.
- I do not see well enough to do my best at work.
- I do not see well enough to do the things I need to do at home.
- I do not see well enough to do the things I like to do (read, watch TV, sew, hike, play cards, go out with friends).
- I am afraid I will bump into something or fall.
- Because of my cataract, I am not as independent as I would like to be.
- My glasses do not help me see well enough.
- My eyesight bothers me a lot.
- Other problems (discuss these with your doctor).
Agency for Health Care Policy and Research
AHCPR offers a free copy of their guidelines on cataracts (Publication Number 93-0544).
5600 Fishers Lane
Rockville, MD 20857
Phone: (301) 427-1364
American Academy of Ophthalmology
You can receive the publications Cataract and Cataract Surgery by sending a business size, self-addressed, stamped envelope with 29 cents postage to:
American Academy of Ophthalmology Inquiry Clerk
Department: Cataract and Cataract Surgery Brochures
P.O. Box 7424
San Francisco, CA 94120-7424
National Society to Prevent Blindness
This organization has set up a hotline to answer questions and distribute literature on eye diseases.
American Association of Retired Persons
You can receive the publication The Eyes Have It, which explains cataracts and other diseases of the aging eye, by writing to:
American Association of Retired Persons
Health Advocacy Services
1909 K Street, N.W.
Washington, DC 20049