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More About Diabetic Retinopathy
Diabetic Retinopathy is one of the scariest (to me) health risks we have as a diabetic.
The thought of losing my eyesight doesn't bear thinking about, which is why I am so
careful about getting an in-depth eye-check every year.
Knowing as much as possible about diabetic eye disease gives us the armour we
need to protect ourselves. The information below is extracted from a very informative
website (with their permission). I've included it here for your convenience, but
you can visit the original website if you wish - the link is at the bottom of this page.
Diabetic eye disease refers
to a group of eye problems that people with diabetes may face as a complication
of diabetes. All can cause severe vision loss or even blindness.
Diabetic eye disease may include:
- Diabetic retinopathy — damage to the blood vessels in the retina.
- Cataract — clouding of the eye's lens.
Cataracts develop at an earlier age in people with diabetes.
- Glaucoma — increase in fluid pressure inside
the eye that leads to optic nerve damage and loss of vision. A person with
diabetes is nearly twice as likely to get glaucoma as other adults.
Diabetic retinopathy is the
most common diabetic eye disease and a leading cause of blindness in American
adults. It is caused by changes in the blood vessels of the retina. In some
people with diabetic retinopathy, blood vessels may swell and leak fluid. In
other people, abnormal new blood vessels grow on the surface of the retina. The
retina is the light-sensitive tissue at the back of the eye. A healthy retina is
necessary for good vision. If you have diabetic retinopathy, at first you may
not notice changes to your vision. But over time, diabetic retinopathy can get
worse and cause vision loss. Diabetic retinopathy usually affects both eyes.
Diabetic
retinopathy has four stages:
- Mild Nonproliferative Retinopathy. At this earliest stage, microaneurysms occur. They are small
areas of balloon-like swelling in the retina's tiny blood vessels.
- Moderate Nonproliferative Retinopathy. As the disease progresses, some blood vessels that nourish
the retina are blocked.
- Severe Nonproliferative Retinopathy. Many more blood vessels are blocked, depriving several areas
of the retina with their blood supply. These areas of the retina send signals
to the body to grow new blood vessels for nourishment.
- Proliferative Retinopathy. At this advanced stage, the signals sent by the retina for
nourishment trigger the growth of new blood vessels. This condition is called
proliferative retinopathy. These new blood vessels are abnormal and fragile.
They grow along the retina and along the surface of the clear, vitreous gel
that fills the inside of the eye. By themselves, these blood vessels do not
cause symptoms or vision loss. However, they have thin, fragile walls. If they
leak blood, severe vision loss and even blindness can result.
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Blood
vessels damaged from diabetic retinopathy can cause vision loss in two ways:
- Fragile, abnormal blood vessels can develop and leak blood into the center
of the eye, blurring vision. This is proliferative retinopathy and is the fourth and most
advanced stage of the disease.
- Fluid can leak into the center of the macula, the part of the eye where
sharp, straight-ahead vision occurs. The fluid makes the macula swell,
blurring vision. This condition is called macular edema. It can occur
at any stage of diabetic retinopathy, although it is more likely to occur as
the disease progresses. About half of the people with proliferative
retinopathy also have macular edema.
 Normal vision
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 Same scene viewed by a person with
diabetic retinopathy
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All people with diabetes--both type 1 and type 2--are at risk.
That's why everyone with diabetes should get a comprehensive dilated eye exam at
least once a year. The longer someone has diabetes, the more likely he or she
will get diabetic retinopathy. Between 40 to 45 percent of Americans diagnosed
with diabetes have some stage of diabetic retinopathy.
If you have diabetic retinopathy, your doctor can
recommend treatment to help prevent its progression. During pregnancy, diabetic
retinopathy may be a problem for women with diabetes. To protect vision, every
pregnant woman with diabetes should have a comprehensive dilated eye exam as
soon as possible. Your doctor may recommend additional exams during your
pregnancy.
If you have diabetes
get a comprehensive dilated eye exam at least once a year and remember:
- Proliferative retinopathy can develop
without symptoms. At this advanced stage, you are at high risk for vision
loss.
- Macular edema can develop
without symptoms at any of the four stages of diabetic retinopathy.
- You can develop both proliferative retinopathy and
macular edema and still see fine. However, you are at high risk for vision
loss.
- Your eye care professional can tell if you have macular edema or any stage
of diabetic retinopathy. Whether or not you have symptoms, early detection and
timely treatment can prevent vision loss.
If you have diabetic retinopathy, you may need an eye exam more often.
People with proliferative retinopathy can reduce their risk of blindness by 95
percent with timely treatment and appropriate follow-up care.
The
Diabetes Control and Complications Trial (DCCT) showed that better control of
blood sugar levels slows the onset and progression of retinopathy. The people
with diabetes who kept their blood sugar levels as close to normal as possible
also had much less kidney and nerve disease. Better control also reduces the
need for sight-saving laser surgery. This level of blood sugar control may not
be best for everyone, including some elderly patients, children under age 13, or
people with heart disease.
Be sure
to ask your doctor if such a control program is right for you. Other studies
have shown that controlling elevated blood pressure and cholesterol can reduce
the risk of vision loss. Controlling these will help your overall health as well
as help protect your vision.
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Often there
are no symptoms in the early stages of the disease, nor is there any pain.
Don't wait for symptoms. Be sure to have a comprehensive dilated eye exam
at least once a year. Blurred vision may occur when the macula—the part of the
retina that provides sharp central vision—swells from leaking fluid. This
condition is called macular edema. If new blood vessels grow on the surface of
the retina, they can bleed into the eye and block vision.
At first, you will see a few specks of
blood, or spots, "floating" in your vision. If spots occur, see your eye care
professional as soon as possible. You may need treatment before more serious
bleeding occurs. Hemorrhages tend to happen more than once, often during sleep.
Sometimes, without treatment, the spots clear, and you will see better. However,
bleeding can reoccur and cause severely blurred vision. You need to be examined
by your eye care professional at the first sign of blurred vision, before more
bleeding occurs.
If left untreated, proliferative retinopathy can cause severe vision
loss and even blindness. Also, the earlier you receive treatment, the more
likely treatment will be effective.
Diabetic retinopathy and macular edema are detected during a
comprehensive eye exam that includes:
- Visual acuity test. This
eye chart test measures how well you see at various distances.
- Dilated eye exam. Drops
are placed in your eyes to widen, or dilate, the pupils. This allows the eye
care professional to see more of the inside of your eyes to check for signs of
the disease. Your eye care professional uses a special magnifying lens to
examine your retina and optic nerve for signs of damage and other eye
problems. After the exam, your close-up vision may remain blurred for several
hours.
- Tonometry. An instrument measures the pressure inside the eye.
Numbing drops may be applied to your eye for this test.
Your eye care
professional checks your retina for early signs of the disease, including:
- Leaking blood vessels.
- Retinal swelling (macular edema).
- Pale, fatty deposits on the retina--signs of leaking blood vessels.
- Damaged nerve tissue.
- Any changes to the blood vessels.
If your eye care professional
believes you need treatment for macular edema, he or she may suggest a
fluorescein angiogram. In this test, a special dye is injected into your
arm. Pictures are taken as the dye passes through the blood vessels in your
retina. The test allows your eye care professional to identify any leaking blood
vessels and recommend treatment.
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During the first three stages of diabetic retinopathy, no treatment
is needed, unless you have macular edema. To prevent progression of diabetic
retinopathy, people with diabetes should control their levels of blood sugar,
blood pressure, and blood cholesterol. Proliferative retinopathy is treated with
laser surgery. This procedure is called scatter laser treatment. Scatter laser
treatment helps to shrink the abnormal blood vessels.
Your doctor places
1,000 to 2,000 laser burns in the areas of the retina away from the macula,
causing the abnormal blood vessels to shrink. Because a high number of laser
burns are necessary, two or more sessions usually are required to complete
treatment. Although you may notice some loss of your side vision, scatter laser
treatment can save the rest of your sight.
Scatter laser treatment may slightly reduce your color vision and
night vision. Scatter laser treatment works better before the fragile, new blood
vessels have started to bleed. That is why it is important to have regular,
comprehensive dilated eye exams. Even if bleeding has started, scatter laser
treatment may still be possible, depending on the amount of bleeding. If the
bleeding is severe, you may need a surgical procedure called a vitrectomy.
(hyperlink to question What is a vitrectomy?) During a vitrectomy, blood is
removed from the center of your eye.
Macular edema is treated with laser surgery. This procedure is
called focal laser treatment. Your doctor places up to several hundred small
laser burns in the areas of retinal leakage surrounding the macula. These burns
slow the leakage of fluid and reduce the amount of fluid in the retina.
The surgery is usually completed in one session.
Further treatment may be needed. A patient may need focal laser surgery more
than once to control the leaking fluid. If you have macular edema in both eyes
and require laser surgery, generally only one eye will be treated at a time,
usually several weeks apart. Focal laser treatment stabilizes vision. In fact,
focal laser treatment reduces the risk of vision loss by 50 percent. In a small
number of cases, if vision is lost, it can be improved. Contact your eye care
professional if you have vision loss.
Both focal and scatter laser treatment are performed in your
doctor's office or eye clinic. Before the surgery, your doctor will dilate your
pupil and apply drops to numb the eye. The area behind your eye also may be
numbed to prevent discomfort. The lights in the office will be dim. As you sit
facing the laser machine, your doctor will hold a special lens to your eye.
During the procedure, you may see flashes of light. These flashes eventually may
create a stinging sensation that can be uncomfortable.
You will need someone to drive you home after surgery.
Because your pupil will remain dilated for a few hours, you should bring a pair
of sunglasses. For the rest of the day, your vision will probably be a little
blurry. If your eye hurts, your doctor can suggest treatment. Laser surgery and
appropriate follow-up care can reduce the risk of blindness by 90 percent.
However, laser surgery often cannot restore vision that has already been lost.
That is why finding diabetic retinopathy early is the best way to prevent vision
loss.
If you have a
lot of blood in the center of the eye (vitreous gel), you may need a vitrectomy
to restore your sight. If you need vitrectomies in both eyes, they are usually
done several weeks apart. A vitrectomy is performed under either local or
general anesthesia. Your doctor makes a tiny incision in your eye. Next, a small
instrument is used to remove the vitreous gel that is clouded with blood. The
vitreous gel is replaced with a salt solution. Because the vitreous gel is
mostly water, you will notice no change between the salt solution and the
original vitreous gel.
You will probably be able to return home after the vitrectomy. Some people stay
in the hospital overnight. Your eye will be red and sensitive. You will need to
wear an eye patch for a few days or weeks to protect your eye. You also will
need to use medicated eyedrops to protect against infection.
Yes. Both treatments are very effective
in reducing vision loss. People with proliferative retinopathy have less than a
five percent chance of becoming blind within five years when they get timely and
appropriate treatment. Although both treatments have high success rates, they do
not cure diabetic retinopathy. Once you have proliferative retinopathy,
you always will be at risk for new bleeding. You may need treatment more than
once to protect your sight.
If you have lost some sight from diabetic retinopathy, ask your
eye care professional about low vision services and devices that may help you
make the most of your remaining vision. Ask for a referral to a specialist in
low vision. Many community organizations and agencies offer information about
low vision counseling, training, and other special services for people with
visual impairments. A nearby school of medicine or optometry may provide low
vision services.
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The National Eye Institute
(NEI) is conducting and supporting research that seeks better ways to detect,
treat, and prevent vision loss in people with diabetes. This research is
conducted through studies in the laboratory and with patients. For example,
researchers are studying drugs that may stop the retina from sending signals to
the body to grow new blood vessels. Someday, these drugs may help people control
their diabetic retinopathy and reduce the need for laser surgery.
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Content last reviewed April 2006
This online resource guide provides information about diabetic eye disease.
(Visit http://www.nei.nih.gov/health/diabetic/ for more useful
information)
It answers questions about causes and symptoms, and discusses diagnosis
and types of treatment. It was adapted from Don't Lose Sight of Diabetic Eye
Disease (NIH Publication No. 04-3252) and Diabetic Retinopathy: What You
Should Know (NIH Publication No. 03-2171). The National Eye Institute (NEI)
conducts and supports research that leads to sight-saving treatments and plays a
key role in reducing visual impairment and blindness. The NEI is part of the
National Institutes of Health (NIH), an agency of the U.S. Department of Health
and Human Services.
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