If you have diabetes mellitus, your body does not metabolize sugar properly. Diabetes can cause high blood-sugar levels which cause excessive thirst and urination. It can also damage the body's blood vessels, the veins and arteries that carry blood throughout your body. Since diabetes destroys the blood vessels to the eye, it can affect vision by causing cataracts, glaucoma and, most importantly, damaging to blood vessels to the retina, the nervous tissue of the eye.
What is diabetic retinopathy?
Diabetic retinopathy is caused by diabetic damage to the blood vessels of the eye. The retina is a nerve layer at the back of the eye that senses light and transmits images to your brain for you to see. When blood vessels in the retina are damaged, they may cause the retina to swell, or they may grow fragile, branches and scar tissue. This can cause permanant blindness by blurring or distorting the images that the retina sends to the brain. Diabetic retinopathy is the leading cause of treatable blindness among adults in the United States. People with untreated diabetes are said to be 25 times more at risk for blindness than people without diabetes.
Diabetes damages blood vessels in the retina, and can cause them to leak fluid or grow abnormally. The longer a person has diabetes, especially untreated diabetes, the more the risk of developing diabetic retinopathy increases. 80% of the people who have had diabetes for at least 15 years have some blood vessel damage to their retina. People with juvenile onset diabetes (Type I) are more likely to develop diabetic retinopathy at a younger age.
Fortunately, it's important for the diabetic to know that today, with improved methods of diagnosis and treatment, only a small percentage of people who develop retinopathy have serious vision problems.
Types of diabetic retinopathy
Background retinopathy is an early stage of diabetic retinopathy. In this stage, blood vessels within the retina become leaky. Leaking fluid causes the retina to swell and to form deposits called exudates. This leaking can affect your vision because it can distort the part of the retina that sees fine details, like letters or numbers. This problem is called macular edema. Reading and close work like cooking or sewing become more difficult because of this condition.
Proliferative diabetic retinopathy describes what occurs when new, abnormal blood vessels begin growing on the retina, into the vitreous (which is the clear, jelly-like substance that fills the center of the eye), or on the iris. The abnormal growth is called neovascularization. These new blood vessels have much weaker walls than normal blood vessels and often break and bleed. If they bleed into the vitreous, they can cause sudden blindness. Sometimes they grow scar tissue that can pull the retina away from the back of the eye. This is called a retinal detachment. If left untreated, a retinal detachment can cause severe permanant vision loss. Abnormal blood vessels may also grow around the pupil (on the iris) causing painful glaucoma by increasing pressure within the eye.
Proliferative diabetic retinopathy is the most serious form of diabetic eye disease. It affects up to 20% of diabetics and can cause severe permanant loss of sight, including permanant blindness, and severely painful glaucoma.
What are the symptoms of diabetic retinopathy?
There are usually no symptoms of background retinopathy, although gradual blurring of vision may occur if macular edema is present. You may never notice changes in your vision, even with severe diabetic retinopathy. A medical examination by an ophthalmologist (eye M.D.) is the only way to find changes inside your eye.
When bleeding occurs, your sight may become hazy, spotty or even disappear altogether. While it is usually painless, proliferative diabetic retinopathy is a severe form of the disease and often requires immediate medical attention. Pregnancy and high blood pressure may also cause a rapid progression of diabetic retinopathy.
How is diabetic retinopathy diagnosed?
The best protection against diabetic retinopathy is to have regular medical eye
examinations by your ophthal-
How is diabetic retinopathy treated?
Your ophthalmologist will examine your eyes and note how much of your retina is damaged. The mainstay of treatment of diabetic eye disease is to control your blood sugar. Your ophthalmologist will contact your internist who will help you keep you blood sugar under control, preventing many of the damaging effects of diabetes. In many cases patients with diabetic retinopathy do not require specific eye treatment, but you will need to continue having regular eye exams, ranging from yearly to every three months. In other cases, treatment is recommended to prevent the damage of diabetic retinopathy and help improve sight whenever possible.
Laser surgery: This procedure is often helpful in treating the leaking
forms of diabetic retinopathy. A powerful beam of laser light is focused on the damaged
blood vessels. Small bursts of the laser's beam seal leaking retinal vessels to reduce
macular edema. This is called focal laser photocoagulation. For abnormal blood vessel
growth (neovascularization), the laser beam bursts are placed throughout the side areas of
the retina. The small laser scars decrease the abnormal blood vessel growth potential and
help "glue" the retina to the back of the eye, preventing retinal detachment. If
diabetic retinopathy is detected early, laser treatment slows or stops vision loss. Even
in the more advanced stages of the disease (proliferative retinopathy), it significantly
reduces the chance of severe visual impairment.
Vitrectomy: In advanced proliferative diabetic retinopathy, the ophthalmologist may recommend a vitrectomy, or removal of the cloudy and diseased vitreous. This delicate surgical procedure is performed in the operating room. Vitrectomy removes the blood-filled vitreous and replaces it with a clear sterile saline solution, or silicone oil solution. The majority of vitrectomy patients notice an improvement in sight after surgery. Sometimes the ophthalmologist may wait from several months to see if the blood clears on its own, before going ahead with a vitrectomy.
Retinal repair: If the new blood vessels or scar tissue detaches the retina from the back of the eye, severe sight loss or permanant blindness can result unless surgery is performed to reattach the retina.
What is your part in treatment?
Diabetes is an illness that affects many body tissues, including the brain, the heart, the kidneys, and the eye. Successful care of diabetes and diabetic retinopathy depends on more than early treatment by your ophthalmologist and internist. Your attitude and attention to medications and diet are essential. You must maintain normal blood sugar levels, avoid smoking and watch your diet and blood pressure.Physical activity is usually no problem for people with background retinopathy. Occasionally, people with active proliferative retinopathy are advised to restrict physical activity.
Early detection and prevention of diabetic retinopathy is the best protection against loss of vision. All people with diabetes should schedule examinations by an ophthalmologist at least once a year for a dilated retinal eye exam. More frequent medical eye examinations may be necessary once some diabetic retinopathy has been diagnosed. With careful monitoring, the ophthalmologist can begin treatment before sight is affected. Laser and operative surgery are highly effective treatment for diabetic retinopathy.