What is a cataract?
The lens inside the
human eye naturally undergoes compression, hardening, and certain
chemical modifications. As these changes occur, the lens takes on a
yellow or brownish hue and loses its clarity. Some degree of lens
hardening and discoloration is normal as a person ages and may not
interfere with visual function. Symptomatic cataracts are present
when the levels of hardening and discoloration significantly degrade
the original transparency and optical quality of the human
lens.
Who gets cataracts?
Cataracts are very
common in older adults. Visually significant cataracts develop in
approximately 50% of people between the age of 65 and 74. About 70%
of people over 75 have cataracts. While most cataracts develop in
older adults they can occur in younger people, including
newborns.
What causes
cataracts?
Cataract formation
depends upon several factors, and is not yet completely understood.
Cataract formation occurring in otherwise healthy adults occurs as a
result of compression and hardening of the center of the lens over
time. This compression causes a breakdown in the lens proteins and
decreases the transparency and clarity of the lens. Pediatric
cataracts result from genetic and metabolic diseases, maternal
infection, toxic or traumatic causes, as well as being hereditary.
Ultraviolet radiation in sunlight, cigarette smoking, and the use of
certain medications are among the risk factors for cataract
development. Cataracts usually develop in both eyes, but often at
different rates.
Can cataracts be
prevented?
Unfortunately there
is no proven medical treatment to prevent, delay, or reverse the
development of cataracts in adults. Many medical agents are under
investigation, but none have been proven absolutely effective. There
is evidence however that anti-oxidants, specifically vitamins A, C,
and E may delay the development of cataracts.
What are the symptoms of
cataracts?
Cataracts can cause
many different visual effects. Some types of cataracts can reduce
close vision more than far vision and visa versa. Some cataracts will
reduce distance and near vision. Cataracts often increase glare that
creates halos around headlights or street lights. Glare can also
significantly decrease vision on very bright days. Cataracts can also
change the power of the human lens and thus the lens power needed for
glasses. Some people find that as cataracts develop their need for
glasses or their spectacle prescription also changes. Occasionally,
the loss of optical quality due to cataract can also lead to double
vision in one eye.
How are cataracts
diagnosed?
A comprehensive
dilated eye examination by an optometric physician will determine if
you have cataracts. Specialized instrumentation is required to
properly evaluate the clarity and optical integrity of the lens
through a dilated pupil.
How are cataracts
treated?
If a diagnosed
cataract develops to a point that a person's daily activities become
effected, referral to a surgeon for cataract removal is made. Not all
eye surgeons are cataract surgeons. Most optometric physicians work
closely with cataract surgeons and participate in the preoperative
and postoperative care of the patient. Cataract surgery involves a
variety of techniques using ultrasound to break up the cataract and
remove it from the eye. Placed into the eye at the time of surgery is
an artificial plastic lens to restore vision. Many cataract surgeons
will not use any sutures after surgery. Cataract surgery performed by
a skilled surgeon carries a success rate of about 95%.
Is surgery the only way to
treat cataracts?
Your optometric
physician can prescribe changes in your eyewear that will help you
see more clearly until surgery is necessary. However surgery is the
only proven means of effectively treating cataracts that have
significantly degraded the quality of vision.
When will I need to have
cataracts removed?
The most common
indication for cataract surgery is the desire for improved visual
function. The patient and optometric physician together determine if
surgery will help when reduced visual function interferes
substantially with desired activities. Many agencies have vision
requirements for such activities as driving, flying aircraft, and
operating equipment. A person who does not meet certain vision
standards may be helped by cataract surgery.
What happens after cataract
surgery?
Immediately following
cataract surgery, an individual may return to their optometric
physician for the necessary after surgery care. The surgeon and
optometric physician communicate their examination findings with each
other to optimize the care of the patient. Years ago the recovery
time from cataract surgery may have lasted for many months. In the
hands of an optometric physician and a skilled surgeon the recovery
time from cataract surgery is now typically only weeks.