Eye disorder
that can occur with little warning is a cataract, which is
clouding of the lens within the eye. The lens is composed of
water and protein. The protein is arranged so that light can
pass through and focus on the retina. If the protein clumps
together, however, it starts to cloud over a small area of the
lens. In time, this cloudy mass of protein — called a cataract
— can grow larger, making it hard to see. That's when it
becomes a problem.
Cataracts are painless. Often people with
cataracts begin to complain about glare. "When these people
have bright lights shined on them, their vision may drop
rather dramatically." Colors may seem faded, and eyeglasses or
contact lenses may need frequent changing. People with
cataracts may need increased light to read.
If the cataract worsens surgery may be
necessary to remove the cloudy lens and replace it with a new
lens.
By the year 2020, there will be more than
12 million individuals in the 65 or older age group who
will probably need treatment for cataracts.
Besides age, other factors that scientists
believe may put individuals at greater risk for developing a
cataract include heredity, alcohol use, smoking, long-term
exposure to high levels of the sun's ultraviolet rays, some
medications and systemic disorders such as diabetes.
The lens of eye is an important part of seeing
clearly. It focuses light onto the retina. In cataract
surgery, the affected lens is removed and, therefore usually
needs to be replaced. Currently, there are three types of
substitute lenses: an intraocular lens (IOL), a contact lens
or cataract glasses. About 90 percent of people who need to
replace their lens choose an IOL. Of them, about 90 percent
achieve 20/40 vision or better.
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Intraocular lens:
An IOL is a clear synthetic lens that is placed in the eye
during cataract surgery. It requires no care. With an IOL,
patients have better vision and won't feel or see the new
lens. A few people cannot have an IOL because they're
sensitive to the material the lens is made of, their eye
structure isn't suitable, or they have certain other eye
diseases.