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Definition
of Cataract
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A cataract is a clouding of the normally
clear lens of the eye. A cataract decreases
the amount of light that is focused on the
retina, resulting in an overall blurriness
of images. Having a cataract disturbs vision
much like looking through a fogged windshield.
The lens is the part of the eye that helps
focus light on the retina.
The retina is the eye's light-sensitive
layer that sends visual signals to the brain.
In a normal eye, light passes through the
lens and gets focused
on the retina. To help produce a sharp image,
the lens must remain clear. The lens is
made |
Dense cataract
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up of mostly water and protein. The protein is
arranged to let light pass through and focus on
the retina. Sometimes some of the protein clumps
together. This can start to cloud small areas
of the lens, blocking some light from reaching
the retina and interfering with vision.
A cataract can occur in any part of the lens:
In the front, center, or the back part. The front
cataract causes problem in vision as well as causes
glare from the light. Central cataract causes
problem in far vision and may not affect reading.
Posterior cataract causes problem in reading.
A combination of all the 3 forms may also occur.
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Myths
& Facts about Cataract |
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There
are many misconceptions about cataract.
- Cataract is not a curtain
or film that grows over the eye.
- It is not caused by
over using your eyes.
- It does not spread from
one eye to other eye.
- It does not cause irreversible
blindness.
- Cataract does not develop
by use of computer.
- There are no medications,
no eye drops, no exercises, or no glasses
that will cause a cataract to disappear.
- Cataracts do not need
to be “ripe” before they can
be removed.
- Surgery is the only
remedy to remove a cataract.
- At present, laser is
not used to remove a cataract.
- In some people who have
had a cataract surgery, the natural capsule
that supports the intraocular lens becomes
cloudy. Laser
surgery is then used to open
this cloudy capsule, restoring the clear
vision.
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| Night
Time Vision with Normal Eye |
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Night
Time Vision with Cataract |
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Symptoms
of Cataract |
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The most common
symptoms of a cataract are:
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A painless blurring
of vision, as if your glasses are dirty
or scratched. This blurring of vision
is gradually progressive.
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Needing brighter
light to see and read clearly.
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Problems with light.
These can include headlights that seem
too bright at night; glare from lamps
or very bright sunlight; or a halo around
lights.
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Gradual loss of color
vision, or yellowing of colors. As the
cataract develops, its center becomes
more and more yellow, giving everything
a yellowish tinge.
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Appearance of dark
spots or shadows that seem to move when
the eye moves.
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Poor night vision.
Double or multiple visions. The cloudiness
in the lens may occur in more than one
place, so that the light rays that reach
the retina are split, causing double
or multiple images. This symptom often
goes away as the cataract grows.
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A stage where it
may be easier to read without glasses.
It is known as “second sight.” This
is a result of change in shape of lens
due to cataract.
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Frequent prescription
changes in your eyeglasses or contact
lenses.
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Detection
of Cataract |
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A
comprehensive
eye exam by your ophthalmologist
can detect the presence and extent of a cataract,
as well as any other conditions that may be causing
blurred vision or other symptoms. After diagnosis,
regular follow-up care is needed to assure the
best possible correction for the level of impairment.
Cataracts can be successfully treated. Working
together, you and your doctor can develop a plan
that will help you maintain the best possible
vision in spite of the gradual development of
cataracts.
There may be other reasons for visual loss in
addition to the cataract, particularly problems
involving the retina or optic nerve. If these
problems are present, removal of the cataract
may improve vision, but perfect sight may not
be possible.
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Possible
Causes of Cataract
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Age-related cataract:
Most cataracts are related to aging. More
than half of all Americans age 65 and older
have a cataract.
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Congenital cataract:
Some babies are born with cataracts or develop
them in childhood, often in both eyes. These
cataracts may not affect vision. If they do,
they may need to be removed.
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Secondary cataract:
Cataracts are more likely to develop in people
who have certain other health problems, such
as diabetes. Also, cataracts are sometimes
linked to medications such as steroid use
or previous eye surgery.
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Traumatic cataract:
Cataracts can develop soon after an eye injury,
or years later.
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Prevention
of Cataract |
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Cataracts
cannot be prevented because lens changes
occur as the eye ages, however precautions
may slow their development. Dark
glasses should always be worn
to protect from ultraviolet
light rays. Recently, some
researchers believe that antioxidants (vitamin
E, Lutein etc.) may delay the development
of cataract. Avoiding cigarette smoke, heavy
alcohol consumption, and air pollution may
also help. |
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Progression of Cataract |
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How
quickly the cataract develops varies among individuals,
and may vary even between the two eyes. Most age-related
cataracts progress gradually over a period of
years. Other cataracts, especially in younger
people and people with diabetes, may progress
rapidly over a few months. It is not possible
to predict exactly how fast cataracts will develop
in any given person.
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Treatment
of Cataract |
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When
a cataract is small (i.e. cloudiness affecting
only a small part of the lens), you may not notice
any changes in your vision and it may not cause
a problem. Stronger lighting, magnifying lenses,
and eye glasses may alleviate vision problems
caused by early-stage cataracts. However, over
time, the cataract may grow larger and cloud more
of the lens, making it harder to see. There are
no medications, no eye drops, no exercises, or
no glasses that will cause a cataract to disappear
once it is formed. Surgery is the only remedy
to remove a cataract. At a certain point surgery
is performed to improve vision. Today, cataract
surgery is very safe and very effective. At present
lasers cannot be used to remove a cataract. In
some people who have had a cataract surgery, the
natural capsule that supports the intraocular
lens becomes cloudy. Laser
surgery is then used to open this
cloudy capsule, restoring the clear vision.
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Right
Time for Cataract Surgery |
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If your vision cannot
be improved by changing the prescription
of eye glasses and you are limited in doing
your daily routine activities such as driving,
playing golf, watching television, or reading
due to cataract formation, you can consider
cataract surgery. It is not true that a
cataract needs to be “ripe”
before it can be removed. If you have cataracts
in both eyes, your ophthalmologist will
not remove them both at the same time. Each
will be removed separately with an interval
of at least two weeks. Sometimes, a cataract
should be removed even if it doesn't 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. |
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Cataract Surgery
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At
NeoVision, we first determine the presence of
a cataract and evaluate its effect on your vision.
Dr. Tandon
performs a comprehensive
eye exam including a series of sophisticated
tests. A visual
acuity test is performed to assess
your central vision. Refraction
determines how beneficial are your current eye
glasses and whether a change in your glasses will
be helpful. Additional tests include:
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- Tonometry:
It measures the pressure of the aqueous humor
within the eye. This test is helpful in detecting
glaucoma
and monitoring its treatment.
- Keratometry:
It measures the radius of curvature of the cornea.
- A-Scan
Test: It measures the length of
your eye. It helps in determining the refractive
power of the intraocular lens implant that is
used to replace your eye's cloudy lens in cataract
surgery.
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Intraocular
Lens |
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Cataract
surgery is a highly successful procedure. Over
95% of patients experience improved vision, unless
there is a problem with the cornea, retina, optic
nerve or other structures. Cataract surgery is
an outpatient procedure performed under local
or topical anesthesia. First, a small (only 2.8mm)
cut is made on the side of your cornea and a small
instrument, phacoemulsification probe is inserted
through this cut to emulsify and remove the cataract.
The focusing power of the natural lens is restored
by replacing it with a permanent intraocular lens
implant. The initial wound is self-sealing and
no stitches are required to close the wound. In
some people who have had a cataract surgery, the
natural capsule that supports the intraocular
lens becomes cloudy. Laser surgery is then used
to open this cloudy capsule, restoring the clear
vision. After cataract surgery, you will be asked
to avoid heavy lifting, bending or exercise for
2 weeks. You will be asked to use some eye drops
in the operated eye. Your eye will be examined
very frequently during the post-surgery period.
When your eye is healed, second eye can be operated
or a new prescription for eyeglasses is given.
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| After
Cataract / YAG Laser / Posterior Capsulotomy |
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Today,
nearly everyone having modern cataract
surgery will have a lens implant
placed inside their eye at the time
of surgery. These plastic implants,
or artificial lenses, permit rapid
return of vision and avoid the frustrations
associated with contact lenses and
thick aphakic glasses with strong
magnifications.
For removing an eye lens, surgeon
makes a small incision in the front
wall or capsule of the lens and
emulsifies the internal contents
of the lens. However, the back wall
or capsule of the lens is left |
YAG
Laser |
intact,
and the plastic artificial lens
is placed inside the capsule, sometimes
termed by the operating surgeon
"in-the-bag." Over the
next few months or year or two,
a cloudy film or membrane may form,
much like a sheet of wax paper,
across the capsule behind the artificial
lens implant. This cloudy film is
termed a "secondary membrane"
or an "after cataract."
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In past years, such membranes
needed to be cut with a very tiny surgical knife.
To ensure safety and sterility, the procedure
usually required another visit to the operating
room. This opening is necessary only for those
cataract surgery patients whose secondary membrane
becomes sufficiently cloudy to impair a clear
vision.
In recent years,
however, a laser technique has been developed
to cut open this secondary membrane in doctor’s
office. The laser is commonly called " Nd:YAG
laser" or simply “ YAG
laser”. Its real name is "Neodymium-YttriumAluminum-Garnet
laser". The YAG laser can cut the opaque
membranes by creating a series of tiny explosions
in a line or cross pattern. This procedure is
called posterior capsulotomy. Thus, if you experience
impaired vision after cataract surgery, the YAG
laser may promptly restore your vision without
a risk of bleeding or infection
inside the eye.
Some
people believe that the cataract surgery is done
by laser. It is not true. In USA, cataracts are
currently removed surgically by phacoemulsification
method, which is an ultrasound technology. The
YAG laser is used only to treat "after cataracts”
but not to remove the cataracts.
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Secondary
Lens Implants |
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A
few years ago, cataract surgery did not routinely
involve replacing the eye's cloudy lens with a
plastic one. After the lens was removed, people
had to use contact lenses or glasses with thick
lenses. Now, a synthetic lens can be implanted
into the eye, even years after a lens was removed. |
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Cataract
Surgery without
Lens Implant |
Cataract
Surgery after
Secondary Lens Implant |
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Secondary
intraocular lenses are used to improve vision
for people who have had cataract surgery and now
rely on thick glasses or contact lenses. Intraocular
secondary lens implants are small eye lenses (made
of plastic-like material, silicon, or acrylic)
that an eye surgeon can put in your eye. They
are usually 5-6.5mm in diameter, small enough
to be inserted through a self-sealing, no-stitch
incision. After the lens is implanted, you will
have a much clearer vision. Before the operation,
your surgeon will determine the type and power
of lens that is best for you. You probably won’t
be able to feel your new lens, and it never needs
to be handled, adjusted, or cleaned. If cost is
an issue, remember that Medicare and many insurance
plans often cover the costs of cataract surgery
as well as secondary lens implants.
NeoVision Eye Center offers you a vast experience
in diagnosis and management of cataract. You can
be assured that you will receive unsurpassed care.
If you suspect that you or your family member
may have a cataract, please call toll free at
510-431-5511
(Union
City) or 650-962-4626
(Mountain View)
to schedule a comprehensive
eye examination.
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