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Cataract surgery removes the
cloudy defective natural lens of the eye and
replaces it with a clear artificial intraocular lens. |
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A cataract is when the normally clear crystalline
lens within the eye becomes cloudy. A cataract can occur in either
one or both
eyes. It cannot spread from one eye to the other. Cataracts
are the leading cause of correctible blindness in the world,
affecting millions each year.
The crystalline lens is a clear part of
the eye that helps to focus light, or an image, onto 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 will
be
blurred, distorted, and/or discolored.
By far the best method to reduce the
risk of cataract formation is the use of 100% UVa and UVb
blocking sunglasses whenever in the sun. Nutritional
supplements and healthy eating may also reduce the
probability of developing cataracts. Click to see an article
from the American Optometric Association about
Cataract Prevention With Nutrition.
The most common form of cataracts are
associated with aging. By age 80, more than half of
all Americans have either a cataract or have had cataract
surgery.
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.
Age related cataracts start small and
affect only a portion of the lens. A cataract may initially
not cause vision difficulties. Over time, the cloudy area in
the lens may get larger and decrease vision clarity.
To the left of this page is an animated
image of a child and the Eiffel Tower. This animation shows
what can occur from the gradual change of a combination of
multiple vision limitations caused by advancing cataracts.
Cataract symptoms may include:
These symptoms also can be a sign of
other eye problems. Any of these symptoms are cause to be
examined by an eye doctor.
Risk factors
for cataracts include:
-
Age (over about age 60)
-
Certain diseases (diabetes, glaucoma).
-
Personal behavior (smoking,
steroids, alcohol
use).
-
The environment (prolonged exposure
to ultraviolet sunlight).
Initial response to cataracts may be to
add more light to the working environment, change glasses,
add anti-glare coating to glasses, use a magnifying glass,
or change lifestyle. The permanent technique to resolve the most common form of cataracts
is to surgically remove the defective natural lens and replace
it with a clear artificial lens. See
Cataract Surgery Process.
A laser may be used to resolve secondary
subcapsular cataracts.
The cataract will be permanently
eliminated by removal of the defective natural lens and
replacement with a clear artificial lens.
Cataract symptoms and vision
limitations caused by the cataract will be eliminated.
Myopia (nearsighted, shortsighted) vision, hyperopia
(farsighted, longsighted) vision may be eliminated, reducing
the need for glasses.
Monovision,
multifocal artificial lenses,
or accommodating
lenses may increase the ability to see
distant and near objects without reading glasses.
Mobility due to improved vision quality,
ability to maintain a driver's license, reading, social
interaction, hobbies, safety, self-confidence, and
independence all will likely be increased or maintained
after cataract surgery.
Vision and eye health problems due to
conditions other than cataracts, such as glaucoma, macular
degeneration, diabetic retinopathy related damage, etc. will
likely remain after cataract surgery.
A cataract needs to be removed only when
vision loss
interferes with the patient's everyday activities, such as driving,
reading, flying, golf, watching TV, etc. Only the patient can make this decision
after considering the
benefits and risks of cataract surgery.
In most
cases,
delaying cataract surgery for a short while will not cause long-term damage to
the eye or make the surgery more difficult. It would be rare
to need urgent cataract surgery.
A cataract may need to be removed even if it does not
cause vision problems. Cataract removal may be appropriate
if the cataract prevents examination or treatment of
a different eye
problem, such as age-related macular degeneration or
diabetic
retinopathy.
About 46% of cataract patients are 20/20
after cataract surgery without the need for glasses or
contact lenses. About 90% are 20/40 or better without
glasses, which is the
minimum requirement to maintain a driver's license. If the
patients have other ocular health issues such as diabetes,
glaucoma, high myopia, etc., then about 30% are 20/20
without glasses and 80% are 20/40 or better. See
Cataract Surgery Results for more details.
In addition to age related cataracts due
to protein clumping, cataracts may be caused by disease,
medications, trauma to the eyes, exposure to radiation,
steroid use, or diabetes. Congenital cataracts are when a
child is born with a cataract, often in both eyes.
Congenital cataracts are often too small to cause vision
problems and do not progress.
Nuclear cataracts
form in the center of
the natural crystalline lens and affect central vision
first.
Cortical cataracts
form in the outer
edges of the natural crystalline lens and often do not cause
any vision difficulties until they progress toward the
center of the lens.
Subcapsular cataract is when the
outermost tissue of the natural crystalline lens becomes
clouded due to trauma or cell density buildup.
Cataract surgery for extraction with
artificial lens implantation
Cataract surgery for extraction without
lens implant
Laser cataract surgery
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