Cataract
A cataract is a loss of transparency, or clouding, of the normally clear lens of the eye. As one ages, chemical
changes occur in the lens that make it less transparent. The loss of transparency may be so mild vision is hardly
affected or so severe that no shapes or movements are seen, only light and dark. When the lens gets cloudy enough
to obstruct vision to any significant degree, it is called a cataract. Glasses or contact lenses cannot sharpen your
vision if a cataract is present.
The most common cause of cataract is aging. Other causes include trauma, medications such as steroids, systemic
diseases such as diabetes and prolonged exposure to ultraviolet light. Occasionally, babies are born with a cataract.
Reducing the amount of ultraviolet light exposure by wearing a wide-brim hat and sunglasses may reduce your risk for
developing a cataract but once developed there is no cure except to have the cataract surgically removed. Outpatient
surgical procedures can remove the cataract through either a small incision (phacoemulsification) or a large incision
(extracapsular extraction). The time to have the surgical procedure is when your vision is bad enough that it
interferes with your lifestyle.
Cataract surgery is a very successful operation. One and a half million people have this procedure every year and
95% have a successful result. As with any surgical procedure, complications can occur during or after surgery and
some are severe enough to limit vision. But in most cases, vision, as well as quality of life, improves.
Cataract Symptoms
Your eye works a lot like a camera. Light rays focus through your lens on the retina, a layer of light sensitive
cells at the back of the eye. Similar to film, the retina allows the image to be "seen" by the brain. But over
time the lens can become cloudy and prevent light rays from passing clearly through the lens. This cloudy lens
is called a cataract.
The typical symptom of cataract formation is a slow, progressive, and painless decrease in vision. Other changes
include: blurring of vision; glare, particularly at night; frequent eyeglass prescription change; a decrease in
color intensity; a yellowing of images; and in rare cases, double vision.
Ironically as the lens gets harder, farsighted or hyperopic people experience improved distance vision and are less
dependent on glasses. However, nearsighted or myopic people become more nearsighted or myopic, causing distance
vision to be worse. Some types of cataracts affect distance vision more than reading vision. Others affect reading
vision more than distance vision.
Intraocular Lenses (IOLs)
An intraocular lens (IOL) is a tiny, lightweight, clear plastic disk placed in the eye during cataract surgery. An
IOL replaces the focusing power of the eye's natural lens.
The lens of the eye plays an important role in focusing images on the retina. If the lens loses its clarity, as it
does when a cataract develops, light rays do not focus clearly and the image one sees is blurry. Glasses or contact
lenses cannot sharpen vision if a cataract is present.
The only treatment for a cataract is to remove the lens and implant an IOL. Intraocular lenses have many advantages.
Unlike contact lenses, which must be removed, cleaned, and reinserted, the IOL remains in the eye after surgery.
An IOL may be placed either in front of or behind the iris. Behind the iris is the most frequent placement site.
They can be hard plastic, soft plastic or soft silicone. Soft, foldable lenses can be inserted through a small
incision which shortens recovery time following surgery.
Rapid evolution of IOL designs, materials, and implant techniques have made them a safe and practical way to
restore normal vision after cataract surgery.
Phacoemulsification (Phaco)
Phacoemulsification is a surgical method used to remove a cataract, which is a clouding of the eye's naturally clear
lens. A cloudy lens interferes with light passing through to the retina, the light-sensing layer of cells at the
back of the eye. Having a cataract can be compared to looking at the world through a foggy window.
In phacoemulsification, an ultrasonic oscillating probe is inserted into the eye. The probe breaks up the center
of the lens. The fragments are suctioned from the eye at the same time. A small incision that often does not require
sutures to close can be used since the cataract is removed in tiny pieces. Most of the lens capsule is left behind
and a foldable intraocular lens implant, or IOL, is placed permanently inside to help focus light onto the retina.
Vision returns quickly and one can resume normal activities within a short period of time.
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