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normal eye vs cataract eye |
Cataracts
Overview
A cataract is a clouding of the normally clear
lens of the eye. For people who have cataracts, seeing through cloudy lenses is
a bit like looking through a frosty or fogged-up window. Clouded vision caused
by cataracts can make it more difficult to read, drive a car (especially at
night) or see the expression on a friend's face.
Most cataracts develop slowly and don't
disturb your eyesight early on. But with time, cataracts will eventually
interfere with your vision.
At first, stronger lighting and eyeglasses can
help you deal with cataracts. But if impaired vision interferes with your usual
activities, you might need cataract surgery. Fortunately, cataract surgery is
generally a safe, effective procedure.
Symptoms
Signs and symptoms of cataracts include:
·
Clouded, blurred or
dim vision
·
Increasing difficulty
with vision at night
·
Sensitivity to light
and glare
·
Need for brighter
light for reading and other activities
·
Seeing
"halos" around lights
·
Frequent changes in
eyeglass or contact lens prescription
·
Fading or yellowing of
colors
·
Double vision in a
single eye
At first, the cloudiness in your vision caused
by a cataract may affect only a small part of the eye's lens and you may be
unaware of any vision loss. As the cataract grows larger, it clouds more of
your lens and distorts the light passing through the lens. This may lead to
more-noticeable symptoms.
When to see a doctor
Make an appointment for an eye exam if you
notice any changes in your vision. If you develop sudden vision changes, such
as double vision or flashes of light, sudden eye pain, or sudden headache, see
your doctor right away.
Causes
Most cataracts develop when aging or injury
changes the tissue that makes up the eye's lens. Proteins and fibers in the
lens begin to break down, causing vision to become hazy or cloudy.
Some inherited genetic disorders that cause
other health problems can increase your risk of cataracts. Cataracts can also
be caused by other eye conditions, past eye surgery or medical conditions such
as diabetes. Long-term use of steroid medications, too, can cause cataracts to
develop.
How a cataract forms
A cataract is a cloudy lens. The lens is
positioned behind the colored part of your eye (iris). The lens focuses light
that passes into your eye, producing clear, sharp images on the retina — the
light-sensitive membrane in the eye that functions like the film in a camera.
As you age, the lenses in your eyes become
less flexible, less transparent and thicker. Age-related and other medical
conditions cause proteins and fibers within the lenses to break down and clump
together, clouding the lenses.
As the cataract continues to develop, the
clouding becomes denser. A cataract scatters and blocks the light as it passes
through the lens, preventing a sharply defined image from reaching your retina.
As a result, your vision becomes blurred.
Cataracts generally develop in both eyes, but
not always at the same rate. The cataract in one eye may be more advanced than
the other, causing a difference in vision between eyes.
Types of cataracts
Cataract types include:
·
Cataracts
affecting the center of the lens (nuclear cataracts). A nuclear cataract may at first cause
more nearsightedness or even a temporary improvement in your reading vision.
But with time, the lens gradually turns more densely yellow and further clouds
your vision.
As the cataract slowly progresses, the lens may even turn brown.
Advanced yellowing or browning of the lens can lead to difficulty
distinguishing between shades of color.
·
Cataracts
that affect the edges of the lens (cortical cataracts). A cortical cataract begins as whitish,
wedge-shaped opacities or streaks on the outer edge of the lens cortex. As it
slowly progresses, the streaks extend to the center and interfere with light
passing through the center of the lens.
·
Cataracts
that affect the back of the lens (posterior subcapsular cataracts). A posterior subcapsular cataract starts
as a small, opaque area that usually forms near the back of the lens, right in
the path of light. A posterior subcapsular cataract often interferes with your
reading vision, reduces your vision in bright light, and causes glare or halos
around lights at night. These types of cataracts tend to progress faster than
other types do.
·
Cataracts
you're born with (congenital cataracts). Some people are born with cataracts or develop them during
childhood. These cataracts may be genetic, or associated with an intrauterine
infection or trauma.
These cataracts may also be due to certain conditions, such as
myotonic dystrophy, galactosemia, neurofibromatosis type 2 or rubella.
Congenital cataracts don't always affect vision, but if they do, they're
usually removed soon after detection.
Risk factors
Factors that increase your risk of cataracts
include:
·
Increasing age
·
Diabetes
·
Excessive exposure to
sunlight
·
Smoking
·
Obesity
·
High blood pressure
·
Previous eye injury or
inflammation
·
Previous eye surgery
·
Prolonged use of
corticosteroid medications
·
Drinking excessive
amounts of alcohol
Prevention
No studies have proved how to prevent
cataracts or slow the progression of cataracts. But doctors think several
strategies may be helpful, including:
·
Have
regular eye examinations. Eye
examinations can help detect cataracts and other eye problems at their earliest
stages. Ask your doctor how often you should have an eye examination.
·
Quit
smoking. Ask your doctor
for suggestions about how to stop smoking. Medications, counseling and other
strategies are available to help you.
·
Manage
other health problems. Follow
your treatment plan if you have diabetes or other medical conditions that can
increase your risk of cataracts.
·
Choose
a healthy diet that includes plenty of fruits and vegetables. Adding a variety of colorful fruits and
vegetables to your diet ensures that you're getting many vitamins and
nutrients. Fruits and vegetables have many antioxidants, which help maintain
the health of your eyes.
Studies haven't proved that antioxidants in pill form can
prevent cataracts. But a large population study recently showed that a healthy
diet rich in vitamins and minerals was associated with a reduced risk of
developing cataracts. Fruits and vegetables have many proven health benefits
and are a safe way to increase the amount of minerals and vitamins in your
diet.
·
Wear
sunglasses. Ultraviolet
light from the sun may contribute to the development of cataracts. Wear
sunglasses that block ultraviolet B (UVB) rays when you're outdoors.
·
Reduce
alcohol use. Excessive
alcohol use can increase the risk of cataracts.
Diagnosis
To determine whether you have a cataract, your
doctor will review your medical history and symptoms, and perform an eye
examination. Your doctor may conduct several tests, including:
·
Visual
acuity test. A visual acuity
test uses an eye chart to measure how well you can read a series of letters.
Your eyes are tested one at a time, while the other eye is covered. Using a
chart or a viewing device with progressively smaller letters, your eye doctor
determines if you have 20/20 vision or if your vision shows signs of
impairment.
·
Slit-lamp
examination. A slit lamp
allows your eye doctor to see the structures at the front of your eye under
magnification. The microscope is called a slit lamp because it uses an intense
line of light, a slit, to illuminate your cornea, iris, lens, and the space
between your iris and cornea. The slit allows your doctor to view these
structures in small sections, which makes it easier to detect any tiny
abnormalities.
·
Retinal
exam. To prepare for a
retinal exam, your eye doctor puts drops in your eyes to open your pupils wide
(dilate). This makes it easier to examine the back of your eyes (retina). Using
a slit lamp or a special device called an ophthalmoscope, your eye doctor can
examine your lens for signs of a cataract.
·
Applanation
tonometry. This test
measures fluid pressure in your eye. There are multiple different devices
available to do this.
Treatment
When your prescription glasses can't clear
your vision, the only effective treatment for cataracts is surgery.
When to consider
cataract surgery
Talk with your eye doctor about whether
surgery is right for you. Most eye doctors suggest considering cataract surgery
when your cataracts begin to affect your quality of life or interfere with your
ability to perform normal daily activities, such as reading or driving at
night.
It's up to you and your doctor to decide when
cataract surgery is right for you. For most people, there is no rush to remove
cataracts because they usually don't harm the eyes. But cataracts can worsen
faster in people with certain conditions, including diabetes, high blood
pressure or obesity.
Delaying the procedure generally won't affect
how well your vision recovers if you later decide to have cataract surgery.
Take time to consider the benefits and risks of cataract surgery with your
doctor.
If you choose not to undergo cataract surgery
now, your eye doctor may recommend periodic follow-up exams to see if your
cataracts are progressing. How often you'll see your eye doctor depends on your
situation.
What happens during
cataract surgery
Cataract surgery involves removing the clouded
lens and replacing it with a clear artificial lens. The artificial lens, called
an intraocular lens, is positioned in the same place as your natural lens. It
remains a permanent part of your eye.
For some people, other eye problems prohibit
the use of an artificial lens. In these situations, once the cataract is
removed, vision may be corrected with eyeglasses or contact lenses.
Cataract surgery is generally done on an
outpatient basis, which means you won't need to stay in a hospital after the
surgery. During cataract surgery, your eye doctor uses a local anesthetic to
numb the area around your eye, but you usually stay awake during the procedure.
Cataract surgery is generally safe, but it
carries a risk of infection and bleeding. Cataract surgery increases the risk
of retinal detachment.
After the procedure, you'll have some
discomfort for a few days. Healing generally occurs within a few weeks.
If you need cataract surgery in both eyes,
your doctor will schedule surgery to remove the cataract in the second eye
after you've healed from the first surgery.
Lifestyle and home
remedies
To deal with symptoms of cataracts until you
decide to have surgery, try to:
·
Make sure your
eyeglasses or contact lenses are the most accurate prescription possible
·
Use a magnifying glass
to read if you need additional help reading
·
Improve the lighting
in your home with more or brighter lamps
·
When you go outside
during the day, wear sunglasses or a broad-brimmed hat to reduce glare
·
Limit your night
driving
Self-care measures may help for a while, but
as the cataract progresses, your vision may deteriorate further. When vision
loss starts to interfere with your everyday activities, consider cataract
surgery.
Preparing for your
appointment
Make an appointment with your usual eye care
provider if you notice changes in your vision. If your doctor determines that
you have cataracts, then you may be referred to an eye specialist who can
perform cataract surgery.
Because there's often a lot to talk about,
it's a good idea to be well prepared for your appointment so that you can make
the most of your time with your doctor. Here's some information to help you get
ready.
What you can do
·
List
any symptoms you're experiencing, including any that may seem unrelated to the reason for
which you scheduled the appointment.
·
Make
a list of all medications, vitamins
or supplements that you're taking.
·
Take
a family member or friend along. Sometimes it can be difficult to absorb all the
information provided during an appointment. Someone who accompanies you may
remember something that you missed or forgot.
·
List
questions to ask your doctor.
For cataracts, some basic questions to ask
your doctor include:
·
Are cataracts causing
my vision problems?
·
What kinds of tests do
I need?
·
Will cataract surgery
correct my vision problems?
·
What are the potential
risks of cataract surgery? Are there risks in delaying surgery?
·
What will cataract
surgery cost, and will my insurance cover it?
·
How much time will I
need to recover from cataract surgery?
·
Will any usual
activities be restricted after cataract surgery? For how long?
·
After cataract
surgery, how long should I wait before getting new glasses?
·
If I use Medicare,
will it cover the cost of cataract surgery? Does Medicare cover the cost of new
glasses after surgery?
·
If I don't want
surgery right now, what else can I do to cope with my vision changes?
·
How will I know if my
cataracts are getting worse?
·
I have these other
health conditions. How can I best manage these conditions together?
·
Are there any
brochures or other printed material that I can take with me? What websites do
you recommend?
In addition to the questions that you've
prepared to ask your doctor, don't hesitate to ask questions at any time that
you don't understand something.
What to expect from
your doctor
Your doctor is likely to ask you a number of
questions. Being ready to answer them may allow more time later to cover other
points you want to address. Your doctor may ask:
·
When did you begin
experiencing symptoms?
·
Do you have your
symptoms all the time or do they come and go?
·
Do you experience
vision problems in bright light?
·
Have your symptoms
gotten worse?
·
Do your vision
problems make it difficult for you to drive?
·
Do your vision
problems make it difficult to read?
·
Do your vision
problems make it difficult to do your job?
·
Have you ever had an
eye injury or eye surgery?
·
Have you ever been
diagnosed with an eye problem, such as inflammation of your iris (iritis)?
·
Have you ever received
radiation therapy to your head or neck?
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