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What
is a cataract?
A cataract is a clouding of the eye's lens, which lies
behind the iris and the pupil. It works much like a camera lens, focusing light onto the retina at the back of the eye. The
lens also adjusts the eye's focus, letting us see things clearly both up close and far away. A cataract at first has little effect on your vision. You may notice that your vision is blurred a little, like looking
through a cloudy piece of glass. A cataract may cause glare. You may notice when you drive at night that the oncoming lights
cause glare or starursts. Colors may not appear as bright as they once did. No one
knows for sure why the eye's lens changes as we age, forming cataracts. Researchers are gradually identifying factors
that may increase risk of developing cataracts, such as ultraviolet light, steroids, diabetes, and cigarette smoke. What will happen during cataract surgery? Many poeple
consider poor vision an inevitable fact of aging, but cataract surgery is a simple, relatively painless procedure to regain
vision. Cataract surgery is very successful in restoring vision; in fact, it is one of the most frequently performed surgeries
in the United States, with over 1.5 million cataract surgeries done every year. Nine out of ten people who have cataract surgery
regain very good vision, somewhere between 20/20 and 20/40. Once you and your eyecare
practitioner have decided that you will have cataract surgery, the eye surgeon will examine you. Ask the surgeon if you should
continue your usual medications. Your eye will be measured to determine the proper power of the intraocular lens that will
be placed in your eye during surgery. Cataract surgery is usually done on an outpatient basis. You may be asked to skip breakfast,
depening on the time of your surgery. Upon arrival for surgery, you will be given eye drops and perhaps medications to help
you relax. A local anesthetic will make the operation painless. The skin around your
eye will be thoroughly cleansed, and sterile coverings will be placed around your head. Under an operating microscope, a small
incision will be made into the eye. Microsurgical instruments will be used to fragment and suction the cloudy lens from the
eye. The black membrane of the lens (called the posterior capsule) will be left in place. A plastic IOL will be placed inside the eye to replace the natural lens that was removed. The incision will then
be closed. When stitches are used, they rarely need to be removed. When the operation is over, the surgeon will usually place
a shield over your eye. After a short stay in the recovery area, you will be ready to go home. You should plan to have someone
else drive you home.
What is nearsightedness (myopia)? Nearsightedness, or
myopia, is a vision problem experienced by up to one-third of the population. Nearsighted people have difficulty reading highway
signs and seeing other objects at distance, but can see for up-close tasks such as reading or sewing. Myopic people often
have headaches or eyestrain, and might squint or feel fatigued when driving or playing sports. If you experience these symptoms
while wearing your glasses or contact lens, you may need a comprehensive eye examination. Myopia occurs when the eyeball is slightly longer than usual from front to back. This causes light rays to focus
at a point in front of the retina, rather than directly on its surface. Myopia is not a disease, nor does it mean that you
have "bad eyes". It simply means that you have a normal variation in the shape of your eyeball. The degree of variation
determines the need for corrective wear. Myopia usually begins between the ages of
8 and 12 years and nearly always before the age of 20. Often the degree of myopia increases as the body grows rapidly, then
levels off in adulthood. During the years of rapid growth, frequent changes in prescription eyewear may be needed to maintain
clear vision.
What is farsightedness
(hyperopia)? Farsightedness, or hyperopia, is a common vision problem, affecting
about a fourth of the population. People with hyperopia can see distant objects very well, but have difficulty seeing objects
that are up close. This vision problem occurs when light rays entering the eye focus behind the retina, rather than directly
on it. The eyeball of a farsighted person is shorter than normal. Many children are
born with hyperopia, and some of them outgrow it as the eyeball lengthens with normal growth. Farsighted people sometimes
have headaches or eyestrain, and may squint or feel fatigued when performing work at close range. If you get these symptoms
while wearing your glasses or contact lenses, you may need an eye exam and a new prescription.
What is presbyopia? During middle
age, usually beginning in the 40s people experience blurred vision at near points, such as when reading, sewing, or working
at the computer. There's no getting around it - this happens to everyone at some point in their life, even if they never
had a vision problem before. When people develop presbyopia, they find they need to hold books, magazines, newspapers, menus,
and other reading materials at arm's length in order to focus properly. When they perform near work, they may have headaches
or eyestrain, or feel fatigued. Presbyopia is caused by an age-related process, rather
than the way light is refracted, or bent, by the eye (which causes astigmatism, nearsightedness, and farsightedness). Presbyopia
is caused by a slow loss of flexibility within the lens inside your eye. These age-related
changes occur within the proteins in the lens, making the lens harder and less elastic as you age. Age-related changes also
take place in the muscle fibers surrounding the lens. Glasses with bifocal or progressive addition lenses (PALs) are the most
common correction for presbyopia. Bifocal means two points of focus: the main part of the spectacle lens contains
a prescription for nearsightedness or farsightedness, while the lower portion of the lens holds the stronger near prescription
for close work. Progressive Addition Lenses are similar to bifocal lenses,
but they offer a more gradual visual transition between the two prescriptions. Reading
glasses are another choice. They may be worn just while doing close work, and may even be prescribed to wear over the top
of contact lenses (usually worn for distance correction). These glasses may be purchased over-the-counter at a retail store,
or higher-quality versions may be prescribed by your eyecare professional. There
are contact lenses for presbyopes, called multifocal lenses. You can obtain multifocal contact lenses in gas permeable
or soft lens materials. Another type of contact lens correction for presbyopia is monovision, in which one eye wears
a distance prescription, and the other wears a prescription for near vision. The brain learns to favor one eye or the other
for different tasks. Some people are delighted with this solution, while others miss the depth perception they once had. Because the human lens continues to change as you grow older, your presbyopic prescription will
change over time as well. You can expect your eyecare practitioner to prescribe a stronger correction for near work as you
need it. Read more about presbyopia at http://www.varilux.com/.
What is astigmatism? Astigmatism is the most common
vision problem. Sometimes incorrectly called a "stigmatism", astigmatism may accompany nearsightedness or farsightedness.
It is caused by an irregularly shaped cornea and is corrected with glasses or contact lenses. If you have only a small amount
of astigmatism, you may not notice it or have just slightly blurred vision. Sometimes uncorrected astigmatism can give you
headaches or eyestrain, and distort or blur your vision. If your eyeglass or contact
lens prescription contains three parts rather than one, you have some amount of astigmatism. A prescription with three parts
looks like this: -2.75 +1.25 x180 The first
part contains your main spherical correction, while parts two and three show the extent and location of your astigmatism. Astigmatism occurs when the cornea is shaped more like an oblong football than a spherical baseball,
which is the normal shape. The oblong shape causes light rays to focus on two points at the back of your eye, instead of just
one. Astigmatism can be corrected with glasses or contact lenses. Many people with
astigmatism believe that they cannot wear contact lenses, or that only rigid lenses can correct astigmatism, but this is no
longer true. Now there are soft lens designs that correct astigmatism; they are called toric lenses. Toric lenses
have a special correction built into them and may also contain a prescription for nearsightedness or farsightedness if you
need it.
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