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 Encyclopedia - Cataracts

What is a cataract?
How many people get cataracts?
What causes cataracts?
What are the symptoms of cataracts?
What is the treatment for cataracts?
What is involved in cataract surgery?
What happens after cataract surgery?
What are the risks of surgery and what follow-up is needed?

What is a cataract?

The lens of the eye, the part that helps focus light onto the retina which in turn sends the visual signals to the brain (See Anatomy of the Eye), is made mostly of water and protein. When too much protein builds up, it clouds the lens blocking some of the light and impairing vision. That protein build-up is the formation of a cataract. It is not a growth, but rather a clouding or hazing of the lens.

How many people get cataracts?

A significant number of people ages 65 or older have some degree of cataract. In fact, developing cataracts is a normal part of aging. That does not mean, however, that every senior will need treatment for cataract problems.

What causes cataracts?

The cause of cataracts is generally unknown. Most often, cataracts occur as a person ages, called age-related cataracts or more scientifically, nuclear sclerotic cataracts. Cataracts can also result from a variety of environmental conditions and injuries and are called either secondary or traumatic cataracts. Some babies are born with cataracts, called congenital cataracts. Generally, potential risk factors for developing cataracts include but are not limited to:

  • 65 years of age or more
  • Family history of cataracts
  • Smoker or former smoker
  • Grossly over- or underweight
  • Diabetes
  • Have taken steroids or certain other medications
  • Suffered a blunt or penetrating eye injury
  • Excessive, long exposure to UV light

What are the symptoms of cataracts?

Some people compare cataracts to looking through a frosted piece of glass, fog, or film covering their sight. Many don’t even know they have cataracts if the cloudiness has not greatly altered their eyesight. Others with cataracts, however, have lost their ability to perform routine activities. Glare may also be a problem, and many people with cataracts complain of halos around lights.

Additional symptoms include colors that seem faded, a temporary symptom called "second sight" which occurs when people can read again close up without glasses even though they have not done this for years, decreased night vision, and frequent changes in eyeglass or contact lens prescription.

It is important to note, however, that although these symptoms can indicate the formation of cataracts, they can also signal other vision problems. Cataracts develop and grow slowly and cause more pronounced symptoms as they "mature." Patients experiencing any of these symptoms are advised to consult their eye care professional for a thorough evaluation.

What is the treatment for cataracts?

The first step in treating cataracts is detection. To determine whether or not a person has cataracts, an eye care professional conducts a comprehensive eye exam, which includes a visual acuity test, pupil dilation, and a tonometry test to measure the pressure inside the eye. The early stages of cataracts can sometimes be treated with eyeglasses, alternative lenses or a simple change in environmental lighting. For more advanced cataracts that have caused a loss of routine activities or other problems, surgery is the only effective treatment option.

Surgery: Cataract removal is one of the most popular surgeries performed in the United States today. It is safe and highly effective in improving vision. The most common procedure is called extracapsular cataract extraction (ECCE) or phacoemulsification (phaco). In phaco, after making a ¼-inch incision, the surgeon uses sound waves or ultrasonic vibrations to break up the cloudy lens so it can be removed by suction through a tiny hollow tube.

In some instances, eye care professionals may choose an older method of cataract removal in which the entire lens is removed through a ½-inch surgical incision. After a lens is removed, it must be replaced. The most common lens replacement is called the intraocular lens (IOL). An IOL is a clear plastic lens implant that is placed inside the eye permanently, thus requiring no care. Patients do not feel or see the new lens.

When an intraocular lens implant is not the best solution, the doctor may prescribe contact lenses or, in rare cases, corrective eyeglasses as lens replacement.

What is involved in cataract surgery?

Prior to surgery, an eye care professional will conduct a comprehensive eye exam or cataract exam to determine eye health and to use as a guide during the surgery.

The patient is given eye drops to enlarge the pupil of the eye to be operated on, giving the surgeon better access to the lens. Some people choose to remain awake during the procedure and select local anesthesia, which may be administered as eye drops, injections close to the eye, or both. Others require general anesthesia to keep them relaxed throughout the procedure.

Depending on the type used, anesthesia may be given about half an hour before surgery in a pre-operation (pre-op) room or immediately before surgery at the operating table. The anesthesia prevents any pain and helps keep the eye from moving.

When ready, the patient lies back on a table and the eye is gently washed. Then a sheet is placed over the patient’s face with an opening for the surgeon to access the eye. Often, a member of the eye care team (surgeon, nurses, and assistants) provides additional air for increased comfort.

The surgeon generally sits behind the patient and uses a surgical microscope unit that can be swung over the table, to obtain a clear, enhanced image of the eye. Lighting is dimmed. With extracapsular or phaco surgery, an incision less than ¼ inch in measurement is made and the surgeon uses the phaco ultrasonic instrument to break up the cloudy lens, then removes the pieces using suction through a tiny hallow tube. Though the cloudy lens is removed, the surgeon leaves intact the lens capsule or outer covering and inserts an intraocular lens (IOL) through the incision to replace the cloudy lens. The incision heals on its own without stitches. Anesthesia helps prevent any pain or discomfort. Overall, the entire surgical procedure usually takes less than 30 minutes. Sometimes a protective covering is placed over the eye when surgery is completed.

What happens after surgery

Recovery time is scheduled immediately following surgery to allow recuperation from the procedure and anesthesia. Patients generally go home afterward, with the help of another driver because vision may still be impaired.

For a day or two following surgery, patients may experience mild discomfort such as itching or stickiness when blinking. These symptoms usually disappear within 1 to 2 days.

Usually patients return to their surgeon the day after the procedure for their first follow up examination. Surgeons often prescribe eye drops to help minimize the mild inflammation that occurs in the eye after surgery.

The healing process may take weeks, but many patients begin to resume visual activities, such as reading and watching television, shortly after surgery, even with some blurred vision.

What are the risks of surgery and what follow up is needed?

As with any surgery, there are some risks involved in cataract surgery. A rise in the eye’s pressure is why it is essential for patients to follow a strict post-surgery check-up schedule. Because an incision is made in the eye, infection is also a risk, though managed easily with oral or eye-drop antibiotics. Other risks are hemorrhage or retinal detachment. It is important to point out that cataract surgery is common and risks are considered minimal. Patients are advised to discuss all the risks in detail with their eye care professional.

Related topics:


See Eye Exam Types in Eye Health Center.
See Free Eye Tests.


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