Cataract
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A cataract is a clouding of the lens in the eye that affects vision.
Most cataracts are related to aging. Cataracts are very common in older people.
By age 80, more than half of all Americans either have a cataract or have had
cataract surgery.
A cataract can occur in either or both eyes. It cannot spread from one eye to
the other.
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The lens is a clear part of the eye that helps to focus light, or an
image, on the retina. The retina is the light-sensitive tissue at the back
of the eye.
In a normal eye, light passes through the transparent lens to the
retina. Once it reaches the retina, light is changed into nerve signals
that are sent to the brain.
The lens must be clear for the retina to receive a sharp image. If the
lens is cloudy from a cataract, the image you see will be blurred. |
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The lens consists mostly of water and protein. When the protein clumps up, it
clouds the lens and reduces the light that reaches the retina. The clouding may
become severe enough to cause blurred vision. Most age-related cataracts develop
from protein clumpings.
When a cataract is small, the cloudiness affects only a small part of the
lens. You may not notice any changes in your vision. Cataracts tend to "grow"
slowly, so vision gets worse gradually. Over time, the cloudy area in the lens
may get larger, and the cataract may increase in size. Seeing may become more
difficult. Your vision may get duller or blurrier.
As the clear lens slowly colors with age, your vision gradually may acquire a
brownish shade. At first, the amount of tinting may be small and may not cause a
vision problem. Over time, increased tinting may make it more difficult to read
and perform other routine activities. This gradual change in the amount of
tinting does not affect the sharpness of the image transmitted to the
retina.
If you have advanced lens discoloration, you may not be able to identify
blues and purples. You may be wearing what you believe to be a pair of black
socks, only to find out from friends that you are wearing purple socks.
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The risk of cataract increases as you get older. Other risk factors for
cataract include:
- Certain diseases (for example, diabetes).
- Personal behavior (smoking, alcohol use).
- The environment (prolonged exposure to ultraviolet sunlight).
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The most common symptoms of a cataract are:
- Cloudy or blurry vision.
- Colors seem faded.
- Glare. Headlights, lamps, or sunlight may appear too bright. A halo may
appear around lights.
- Poor night vision.
- Double vision or multiple images in one eye. (This symptom may clear as
the cataract gets larger.)
- Frequent prescription changes in your eyeglasses or contact
lenses.
These symptoms also can be a sign of other eye problems. If you have any of
these symptoms, check with your eye care professional.
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Yes. Although most cataracts are related to aging, there are other types of
cataract:
- Secondary cataract. Cataracts can form after surgery for other
eye problems, such as glaucoma. Cataracts also can develop in people who
have other health problems, such as diabetes. Cataracts are sometimes linked
to steroid use.
- Traumatic cataract. Cataracts can develop after an eye injury,
sometimes years later.
- Congenital cataract. Some babies are born with cataracts or develop
them in childhood, often in both eyes. These cataracts may be so small that
they do not affect vision. If they do, the lenses may need to be removed.
- Radiation cataract. Cataracts can develop after exposure to some
types of radiation.
Normal vision |
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The same scene as viewed by a person with cataract |
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- Visual acuity test. This eye chart test measures how well you see
at various distances.
- Dilated eye exam. Drops are placed in your eyes to widen, or dilate,
the pupils. Your eye care professional uses a special magnifying lens to
examine your retina and optic nerve for signs of damage and other eye problems.
After the exam, your close-up vision may remain blurred for several hours.
- Tonometry. An instrument measures the pressure inside the eye.
Numbing drops may be applied to your eye for this test.
Your eye care professional also may do other tests to learn more about the
structure and health of your eye.
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The symptoms of early cataract may be improved with new eyeglasses, brighter
lighting, anti-glare sunglasses, or magnifying lenses. If these measures do not
help, surgery is the only effective treatment. Surgery involves removing the
cloudy lens and replacing it with an artificial lens.
A cataract needs to be removed only when vision loss interferes with
your
everyday activities, such as driving, reading, or watching TV. You and your
eye care professional can make this decision together. Once you understand the
benefits and risks of surgery, you can make an informed decision about whether
cataract surgery is right for you. In most cases, delaying cataract surgery will
not cause long-term damage to your eye or make the surgery more difficult. You
do not have to rush into surgery.
Sometimes a cataract should be removed even if it does not cause problems
with your vision. For example, a cataract should be removed if it prevents
examination or treatment of another eye problem, such as age-related macular
degeneration or diabetic retinopathy.
If you choose surgery, your eye care professional may refer you to a
specialist to remove the cataract.
If you have cataracts in both eyes that require surgery, the surgery will be
performed on each eye at separate times, usually four to eight weeks apart.
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Cataract removal is one of the most common operations performed in the United
States. It also is one of the safest and most effective types of surgery. In
about 90 percent of cases, people who have cataract surgery have better vision
afterward.
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There are two types of cataract surgery. Your doctor can explain the
differences and help determine which is better for you:
- Phacoemulsification, or phaco. A small incision is made on
the side of the cornea, the clear, dome-shaped surface that covers the front
of the eye. Your doctor inserts a tiny probe into the eye. This device emits
ultrasound waves that soften and break up the lens so that it can be removed
by suction. Most cataract surgery today is done by phacoemulsification, also
called "small incision cataract surgery."
- Extracapsular surgery. Your doctor makes a longer incision on the
side of the cornea and removes the cloudy core of the lens in one piece. The
rest of the lens is removed by suction.
After the natural lens has been removed, it often is replaced by an
artificial lens, called an intraocular lens (IOL). An IOL is a clear, plastic
lens that requires no care and becomes a permanent part of your eye. Light is
focused clearly by the IOL onto the retina, improving your vision. You will not
feel or see the new lens.
Some people cannot have an IOL. They may have another eye disease or have
problems during surgery. For these patients, a soft contact lens, or glasses
that provide high magnification, may be suggested.
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As with any surgery, cataract surgery poses risks, such as infection and
bleeding. Before cataract surgery, your doctor may ask you to temporarily stop
taking certain medications that increase the risk of bleeding during surgery.
After surgery, you must keep your eye clean, wash your hands before touching
your eye, and use the prescribed medications to help minimize the risk of
infection. Serious infection can result in loss of vision.
Cataract surgery slightly increases your risk of retinal detachment. Other
eye disorders, such as high myopia (nearsightedness), can further increase your
risk of retinal detachment after cataract surgery. One sign of a retinal
detachment is a sudden increase in flashes or floaters. Floaters are little
"cobwebs" or specks that seem to float about in your field of vision. If you
notice a sudden increase in floaters or flashes, see an eye care professional
immediately. A retinal detachment is a medical emergency. If necessary,
go to an emergency service or hospital. Your eye must be examined by an eye
surgeon as soon as possible. A retinal detachment causes no pain. Early
treatment for retinal detachment often can prevent permanent loss of vision. The
longer the retina stays detached, the less likely you will regain good vision
once you are treated. Even if you are treated promptly, some vision may be
lost.
Talk to your eye care professional about these risks. Make sure cataract
surgery is right for you.
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Many people who need cataract surgery also have other eye conditions, such as
age-related macular degeneration or glaucoma. If you have other eye conditions
in addition to cataract, talk with your doctor. Learn about the risks, benefits,
alternatives, and expected results of cataract surgery.
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A week or two before surgery, your doctor will do some tests. These tests may
include measuring the curve of the cornea and the size and shape of your eye.
This information helps your doctor choose the right type of IOL.
You may be asked not to eat or drink anything 12 hours before your
surgery.
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At the hospital or eye clinic, drops will be put into your eye to dilate the
pupil. The area around your eye will be washed and cleansed.
The operation usually lasts less than one hour and is almost painless. Many
people choose to stay awake during surgery. Others may need to be put to sleep
for a short time. If you are awake, you will have an anesthetic to numb the
nerves in and around your eye.
After the operation, a patch may be placed over your eye. You will rest for a
while. Your medical team will watch for any problems, such as bleeding. Most
people who have cataract surgery can go home the same day. You will need someone
to drive you home.
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Itching and mild discomfort are normal after cataract surgery. Some fluid
discharge is also common. Your eye may be sensitive to light and touch. If you
have discomfort, your doctor can suggest treatment. After one or two days,
moderate discomfort should disappear.
For a few days after surgery, your doctor may ask you to use eyedrops to help
healing and decrease the risk of infection. Ask your doctor about how to use
your eyedrops, how often to use them, and what effects they can have. You will
need to wear an eye shield or eyeglasses to help protect your eye. Avoid rubbing
or pressing on your eye.
When you are home, try not to bend from the waist to pick up objects on the
floor. Do not lift any heavy objects. You can walk, climb stairs, and do light
household chores.
In most cases, healing will be complete within eight weeks. Your doctor will
schedule exams to check on your progress.
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Problems after surgery are rare, but they can occur. These problems can
include infection, bleeding, inflammation (pain, redness, swelling), loss of
vision, double vision, and high or low eye pressure. With prompt medical
attention, these problems usually can be treated successfully.
Sometimes the eye tissue that encloses the IOL becomes cloudy and may blur
your vision. This condition is called an after-cataract. An
after-cataract can develop months or years after cataract surgery.
An after-cataract is treated with a laser. Your doctor uses a laser to make
a tiny hole in the eye tissue behind the lens to let light pass through. This
outpatient procedure is called a YAG laser capsulotomy. It is painless
and rarely results in increased eye pressure or other eye problems. As a
precaution, your doctor may give you eyedrops to lower your eye pressure before
or after the procedure.
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You can return quickly to many everyday activities, but your vision may be
blurry. The healing eye needs time to adjust so that it can focus properly with
the other eye, especially if the other eye has a cataract. Ask your doctor when
you can resume driving.
If you received an IOL, you may notice that colors are very bright. The IOL
is clear, unlike your natural lens that may have had a yellowish/brownish tint.
Within a few months after receiving an IOL, you will become used to improved
color vision. Also, when your eye heals, you may need new glasses or contact
lenses.
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If you have lost some sight from cataract or cataract surgery, ask your eye
care professional about low vision services and devices that may help you make
the most of your remaining vision. Ask for a referral to a specialist in low
vision. Many community organizations and agencies offer information about low
vision counseling, training, and other special services for people with visual
impairments. A nearby school of medicine or optometry may provide low vision
services.
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The National Eye Institute is conducting and supporting a number of studies
focusing on factors associated with the development of age-related cataract.
These studies include:
- The effect of sunlight exposure, which may be associated with an increased
risk of cataract.
- Vitamin supplements, which have shown varying results in delaying the
progression of cataract.
- Genetic studies, which show promise for better understanding cataract
development.
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Wearing sunglasses and a hat with a brim to block ultraviolet sunlight may
help to delay cataract. If you smoke, stop. Researchers also believe good
nutrition can help reduce the risk of age-related cataract. They recommend
eating green leafy vegetables, fruit, and other foods with antioxidants.
If you are age 60 or older, you should have a comprehensive dilated eye exam
at least once every two years. In addition to cataract, your eye care
professional can check for signs of age-related macular degeneration, glaucoma,
and other vision disorders. Early treatment for many eye diseases may save your
sight.
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You can protect yourself against vision loss by working in partnership with
your eye care professional. Ask questions and get the information you need to
take care of yourself and your family.
- What is my diagnosis?
- What caused my condition?
- Can my condition be treated?
- How will this condition affect my vision now and in the future?
- Should I watch for any particular symptoms and notify you if they occur?
- Should I make any lifestyle changes?
- What is the treatment for my condition?
- When will the treatment start and how long will it last?
- What are the benefits of this treatment and how successful is it?
- What are the risks and side effects associated with this treatment?
- Are there foods, drugs, or activities I should avoid while I'm on this
treatment?
- If my treatment includes taking medicine, what should I do if I miss a
dose?
- Are other treatments available?
- What kinds of tests will I have?
- What can I expect to find out from these tests?
- When will I know the results?
- Do I have to do anything special to prepare for any of the tests?
- Do these tests have any side effects or risks?
- Will I need more tests later?
- If you don't understand your eye care professional's responses, ask questions
until you do understand.
- Take notes or get a friend or family member to take notes for you. Or,
bring a tape recorder to help you remember the discussion.
- Ask your eye care professional to write down his or her instructions to
you.
- Ask your eye care professional for printed material about your condition.
- If you still have trouble understanding your eye care professional's answers,
ask where you can go for more information.
- Other members of your health care team, such as nurses and pharmacists,
can be good sources of information. Talk to them, too.
Today, patients take an active role in their health care. Be an active
patient about your eye care.
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National Eye Institute (NEI)
National Marfan Foundation
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