What is diabetes and what is diabetic retinopathy?
Who is at risk for diabetic retinopathy?
What are the symptoms of diabetic retinopathy?
What can be done to prevent or mitigate diabetic retinopathy?
What is the treatment for diabetic retinopathy?
Where can I get more information about diabetic retinopathy?
What
is diabetes and what is diabetic retinopathy?
Diabetes is a chronic, systemic disease in which the body does not use
and store sugar properly. It results in many serious health problems;
diabetic retinopathy is one of them. In this complication of diabetes,
the eye’s light-sensitive retina is damaged because the system
of blood vessels nourishing the retina is weakened. Fragile, new blood
vessels form in the retina; these can then leak fluid into the retina,
and bleed into the vitreous (the jellied, middle part of the eyeball).
Both of these processes can be disastrous for vision. Diabetic retinopathy
is now the leading cause of blindness among America’s working-age
population and is rampant in the Hispanic population.
There are two types of diabetes: Type-1 (insulin-dependent) is an autoimmune disease that usually begins suddenly in late childhood or in adolescence. Type-2 (non-insulin dependent) accounts for over 90 percent of diabetes cases in this country. Type-2 is no longer called “adult-onset diabetes,” because this disease now affects increasing numbers of children. The reason for this is that type-2 diabetes is usually triggered by obesity, and all age groups in our population are becoming heavier. Nearly two-thirds of Americans are now overweight or obese, and a similar epidemic of diabetes is following in the wake of this condition. About 16 million Americans now have diabetes, and it is estimated that one-third of these people are not aware of their illness and do not seek treatment for this life-threatening disease.
Who is at risk for
diabetic retinopathy?
The short answer is that anyone with diabetes (either type) is at great
risk of acquiring diabetic retinopathy. Nearly all diabetics who are
treated with conventional methods of blood-sugar control get some early
changes (called non-proliferative retinopathy) in their retinal blood
vessels after several years. Many diabetics then proceed to symptomatic,
proliferative diabetic retinopathy, in which abnormal, new blood vessels
cause trouble. After living 40 years with the disease, about 60 percent
of all diabetics have this potentially blinding complication.
What are the
symptoms of diabetic retinopathy?
In the early, non-proliferative stage of diabetic retinopathy, the normal
retinal blood vessels become weakened, as some of their cells sicken
and die. This stage may not be noticed by the patient. However, in time,
the new, abnormal blood vessels that form take over and spread (proliferate).
These vessels can leak; this is called macular edema or swelling, and
can cause blurred central vision. In addition, the vessels may bleed,
causing you to see dark spots that won't go away. These spots can be
anywhere in your visual field. Another common eye complication of diabetes
is cataracts.
What can be done
to prevent or mitigate diabetic retinopathy?
No one can now prevent the start of type-1 diabetes (although there
is lots of research in this field). However, there is a nearly sure-fire
way to prevent yourself from suffering from type-2, and that is to maintain
a healthy weight. Being overweight (having a body-mass index over 25)
is a huge risk factor for diabetes, and being obese (BMI over 30) nearly
ensures your getting the disease eventually. If you weigh too much,
then losing even one-tenth of your weight, and keeping it off, can significantly
lower your chance of getting diabetes.
If you are overweight or obese, your doctor should test you periodically for a pre-diabetic condition called glucose intolerance. If this test is positive, then you should be under close supervision by a diabetes specialist and follow the doctor's instructions.
If you already have diabetes, the best way to prevent its complications, including diabetic retinopathy, is to keep your blood-sugar level in the normal range. Take your prescribed medicines and stick to your diet as instructed, even if you feel well, get enough exercise, keep your blood pressure from getting high, and don’t smoke. A recent study, conducted by the National Institute of Diabetes and Digestive and Kidney Diseases, found that very tight control of blood-glucose levels can greatly reduce all the long-term complications associated with diabetes, which affect the eyes, kidney, heart, and nerves.
It is important to have your eyes examined regularly by an eye-care professional, who will get a good view of your retinas after dilating your pupils. Frequent exams are especially valuable if you are a diabetic or a close relative of one. Diabetics should see their eye doctors for a thorough examination through dilated pupils at least once a year, starting when they are first diagnosed with the disease. This is because the doctor can see any retinopathy early enough to treat it, before there is vision loss. Pregnant women with diabetes should schedule an appointment in each trimester, as retinopathy can progress very quickly during pregnancy.
What is the
treatment for diabetic retinopathy?
The treatment of diabetic retinopathy is a success story for clinical
research. A simple laser treatment is effective in sealing off the new
vessels that form in proliferative diabetic retinopathy. In the most
common treatment for proliferative retinopathy, called panretinal photocoagulation,
the laser beam is focused on all parts of the retina except for the
center (the macula). To treat macular edema, the laser is aimed directly
on the damaged blood vessels (as determined by an imaging method called
angiography). So, anyone with diabetes (either type) should have frequent
visits to an eye-care professional, in order to catch new blood vessels
as they form, and seal them off before devastating leakage or bleeding
occurs into the eye. Several laser treatments may be necessary, over
time. Laser surgery cannot cure diabetic retinopathy and cannot always
prevent further vision loss. In advanced cases of retinopathy, a vitrectomy
to remove the blood-filled vitreous may be necessary. The treatment
of diabetic cataracts is surgical removal, as in the case of age-related
cataracts.
If an older person has already been diagnosed with diabetic retinopathy (even in the early, non-proliferative stage), Medicare will pay for future visits.
Much current research is directed at learning the biochemical pathways by which high blood sugar triggers the early pathological changes in the blood vessels of the retina, kidney, heart, and other essential organs. Hopefully, in the future, new, specific treatments can be targeted toward the biological signaling molecules and growth factors involved. There is also progress in developing anti-angiogenesis drugs aimed at inhibiting blood vessel growth.
Where can I get more
information about diabetic retinopathy?
The National Eye Institute (NEI ), a branch of the National Institutes of Health, has lots of reliable, easily understood information available on its web site. For example, you can see what the world looks like with cataracts. Or, find out if free or low-cost eye screenings by eye care professionals are available to qualifying individuals in your area.
All of the NEI information is available, free, by writing to: National Eye Health Education Program, 2020 Vision Place, Bethesda, MD 20892-3655.
Schepens Eye Research Institute, American Diabetes Association and Prevent Blindness America have fact sheets available on diabetic retinopathy and other eye problems.
