http://www.stlukeseye.com/Conditions/Cataracts.asp
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What is a cataract? When cataracts are mentioned, people often think of a
film that grows on their eyes causing them to see double or blurred images.
However, a cataract does not form on the eye, but rather within the eye.
A cataract is a clouding of the natural lens, the part
of the eye responsible for focusing light and producing clear, sharp images.
The lens is contained in a sealed bag or capsule. As old cells die they
become trapped within the capsule. Over time, the cells accumulate causing
the lens to cloud, making images look blurred or fuzzy. For most people,
cataracts are a natural result of aging. In fact, they are the leading cause of visual loss among
adults 55 and older. Eye injuries, certain medications, and diseases such as
diabetes and alcoholism have also been known to cause cataracts.
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The Self-Sealing Incision
hanks to medical and surgical
advancements in recent years, cataract surgery has become one of the
most gentle medical procedures performed today. The restoration of precious
eyesight is accomplished every day at St. Luke's through tiny incisions that do
not even require stitches. The chances of developing astigmatism
(distorted vision) after surgery are significantly decreased by eliminating
stitches, which tend to pull the eye's surface slightly out of its natural
shape. Most patients are now able to enjoy their best possible vision with
minimal recovery time.
This is possible thanks
to a tiny, beveled incision commonly called the "self-sealing"
incision. It is called "self-sealing" because the eye's natural
internal pressure holds the incision tightly closed allowing the eye to heal
without stitches. The self-sealing is made at the edge of the "clear
cornea," and is less than 2.5 mm in length. The clear cornea is the
transparent covering of the front of the eye.
The
cataract is situated inside the lens capsule, which is like an elastic bag that
holds the lens in place. To remove the cataract, the front portion of the lens
capsule is carefully opened. The cataract is gently broken apart using
ultrasonic vibrations and vacuumed out of the lens capsule. This technique is
called phacoemulsification. The lens capsule is left undisturbed so a tiny lens
implant can be inserted in place of the original lens.
Many
types of lenses are used; most are made of either hard plastic or soft, foldable
silicone. Patients will receive the lens best suited for them.
Selecting the Best Implant
For Your Needs
After the cataract is
removed, an intraocular lens is required to replace the focusing power of
the natural lens. The implant provides clearest vision at a single focal
distance. This means that an eye focused for distance will have sharpest vision
for distance activities such as driving, but would still require glasses for
reading. Conversely, an eye focused for close range activities such as reading,
will see best close-up rather than at a distance.
Most patients undergoing
cataract surgery on their first eye receive an implant that provides distance
to intermediate vision. If surgery is required on the second eye, the patient
can elect to have better distance or near vision in that eye depending on their
needs. Patients can reduce their need for glasses by electing to have what is
called "monovision". With monovision, one eye is focused for
near vision and the other for distance to intermediate vision. Over time, the
brain gets used to "looking through" whichever eye is necessary, and
therefore eliminates the need for glasses.