Diabetes
a Risk Factor for Cataracts
Individuals with
diabetes are at 60 percent greater risk for developing cataracts
than persons who do not have diabetes, experts say. And, diabetics
develop cataracts at an earlier age and more quickly than most
persons without diabetes.
In the month of January,
the American Academy of Ophthalmology is alerting
persons with cataracts about new advances in treatment during
Cataract Awareness Month.
In all, nearly 20
million people in the US suffer from cataracts, a condition
where the lens of the eye clouds over, making it difficult or
nearly impossible to see. In fact, blurry vision is one symptom
of diabetes.
Cataracts are a common
symptom of growing old. By age 80, more than half of all Americans
either have a cataract or have had cataract surgery, according
to the National Eye Institute.
Surgical
Advances Improve Treatment
Surgical advances
utilizing ultrasonic devices have made it easier than ever to
remove and replace a cataract-clouded lens, medical experts
say.
Other breakthroughs
involving replacement lenses mean patients often end up with
better vision than they had before surgery.
Most age-related cataracts
develop when protein in the eye's lens begins to clump up, clouding
the lens and reducing the light that reaches the retina.
The lens is a clear
part of the eye that helps to focus light, or an image, on the
retina, the light-sensitive tissue at the back of the eye.
For some people, their
clear lens will slowly change to a yellow-brown color, adding
a brownish tint to vision. This tint can make it more difficult
to read or perform other routine activities.
"Cataract surgery
has been one of the areas of medicine that has seen the most
tremendous advances," says Dr. Donald Schwartz, an ophthalmologist
in Long Beach, Calif., and a spokesman for the American
Academy of Ophthalmology.
One of the biggest
advances has been the perfection of phacoemulsification, the
surgical procedure in which ultrasound waves break up a cataract-ridden
lens, Dr. Schwartz says.
In the procedure,
a small incision is made on the side of the cornea, the clear,
dome-shaped surface that covers the front of the eye. A tiny
probe then is inserted into the eye that emits ultrasound waves
that soften and break up the lens.
"Then those little
tiny pieces are vacuumed out of the eye," says Dr. Thomas Steinemann,
an ophthalmologist and associate professor at Case Western Reserve
University. "Within a few minutes, the cataract is gone."
After the natural
lens has been removed, it often is replaced by an artificial
lens, also called an intraocular lens. The lens requires no
care and becomes a permanent part of the patient's eye.
Surgery also has been
made easier by the creation of synthetic replacement lenses
that can be folded, Dr. Steinemann says. These lenses, often
made of acrylic or solid silicone, can be placed into the eye
through a self-sealing incision as small as an eighth of an
inch.
"You can make your
incision into the eye very tiny," he says. "It's less invasive,
and makes recovery time much shorter." Because the incision
is so tiny, sutures usually aren't needed.
Better
Vision with New Lenses
Improvements in the
lenses also have meant better vision for the people who receive
them.
"We want to replace
the lens with a lens that acts more and more like our own human
lens," Dr. Schwartz notes. "Lenses that will better and better
allow people to see at different distances."
Older lens implants
provided clear vision for people only at one specific distance.
But new so-called multifocal lens implants come closer to mimicking
the sight provided by the human eye.
Formed with concentric
circles resembling a practice target, the lens allows a patient
to shift his or her focus through slight eye movements.
Testing is under way
on a further refinement involving a device called a wavefront
analyzer. The device measures the way light travels through
a cataract patient's entire optical pathway, then compares it
to the way light travels through an optically perfect eye.
The information from
this device can be used to create lenses crafted to address
the specific irregularities of a person's visual system.
"That's still in the
testing stages, but it could eliminate some of the distortion
that patients complain of," Dr. Steinemann remarks.
Cataract
Prevention a Goal
While the advances
are reassuring, no one wants to get cataracts in the first place.
For those individuals
without the risk diabetes poses, "It's almost inevitable that
if you live long enough, you will get cataracts," Dr. Schwartz
says. "A common risk for everyone is sun damage from ultraviolet
light."
"Cataracts are caused
in most people by a lifetime of damage caused by ultraviolet
radiation," Dr. Steinemann says. He recommends that everyone
- even children - wear good sunglasses with ultraviolet protection
when they're out in the sun.
Dr. Steinemann points
out that diabetes is a major risk, especially if it is left
uncontrolled. According to the American Diabetes Association
(ADA), the Diabetes Prevention Program showed that
some medications may delay the development of diabetes, but
that diet and exercise worked better.
ADA
experts say that just 30 minutes a day of moderate physical
activity, coupled with a 5 percent to 10 percent reduction in
body weight, produced a 58 percent reduction in diabetes.
You also should protect
your eyes when necessary, because trauma can spur the early
onset of cataracts.
"Wearing eye protection
is an easy thing to do, and it's critical," Dr. Steinemann says.
He suggests wearing safety glasses or goggles while at work,
playing sports, participating in hobbies, or indulging in any
activity that causes risk to your eyes.
Finally, smoking also
puts you at risk for cataracts, Schwartz said.
"In the center core
of the lens, the nucleus becomes harder and more yellow with
people who smoke," he says.
Always consult your
physician for more information. |
January
2005
Diabetes
a Risk Factor for Cataracts
Surgical
Advances Improve Treatment
Better
Vision with New Lenses
Cataract
Prevention a Goal
Antioxidants
in Leafy, Green Veggies Help
Online
Resources
Antioxidants
in Leafy, Green Veggies Help
A new study from Ohio
State University provides the first lab evidence that certain
antioxidants found in dark, leafy green vegetables can indeed
help prevent cataracts, according to a study in the Journal
of Nutrition.
Vitamin manufacturers
often add the antioxidants lutein and zeaxanthin to their products,
but until now there has been no biochemical evidence to support
the claim that these substances help protect the eyes, says
Joshua Bomser, a study co-author and an assistant professor
of nutrition at Ohio State University.
Some studies have
suggested that these antioxidants boost eye health.
Results from lab experiments
on human lens cells showed that lutein and zeaxanthin, antioxidants
found in plants such as kale, spinach, and collard greens, helped
to protect the cells from exposure to ultraviolet light, a leading
cause of cataract formation.
The researchers compared
the effects of these antioxidants to vitamin E, an antioxidant
also thought to reduce the onset of eye diseases.
Lutein and zeaxanthin
were nearly 10 times more powerful than vitamin E in protecting
the cells from UV-induced damage.
"Along with the many
environmental, lifestyle, and genetic risk factors associated
with cataracts, exposure to ultraviolet radiation from sunlight
and oxidative stress appear to be the most relevant in this
disease," Bomser says. "Our results are the first to provide
physical evidence suggesting that lutein and zeaxanthin decrease
damage caused by ultraviolet radiation."
The researchers treated
human eye lens cells with varying concentrations of lutein,
zeaxanthin, or vitamin E. They then exposed these cells, along
with a batch of untreated cells, to doses of ultraviolet-beta
radiation for 10 seconds.
Adding lutein and
zeaxanthin to the cell cultures provided double the protection
from UVB damage. These antioxidants reduced signs of damage
by 50 to 60 percent, compared to vitamin E, which reduced the
same signs of damage by 25 percent to 32 percent.
The researchers also
found that it took far less lutein and zeaxanthin as vitamin
E, about 10 times less, to get this protective effect.
"The lens is equipped
with antioxidant defense mechanisms designed to guard against
the harmful effects of ultraviolet radiation and oxidative stress,"
Bomser says. "In addition to protective enzymes and compounds
like vitamins C and E, we think that low concentrations of lutein
and zeaxanthin in the eye lens help shield the eye from the
harmful effects of UVB radiation."
What researchers don't
know, however, is how these two antioxidants get into the eye.
It's what Bomser hopes to learn next.
Always consult your
physician for more information.
Online
Resources
(Our Organization
is not responsible for the content of Internet sites.)
American
Diabetes Association
Centers
for Disease Control and Prevention (CDC)
Everyday
Choices, ADA, AHA, and ACS
HealthierUS.Gov
National
Diabetes Education Program
National
Diabetes Information Clearinghouse
National
Institute of Diabetes & Digestive & Kidney Diseases
National
Institutes of Health (NIH)
National
Library of Medicine
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