Diabetic retinopathy is retinopathy (damage to the retina) caused by complications of diabetes mellitus, which can eventually lead to blindness. It is an ocular manifestation of systemic disease which affects up to 80% of all patients who have had diabetes mellitus for 10 years or more. Despite these intimidating statistics, research indicates that at least 90% of these new cases could be reduced if there was proper and vigilant treatment and monitoring of the eyes. The longer a person has diabetes mellitus, the higher his or her chances of developing diabetic retinopathy.
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.
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.
Often there are no visual symptoms in the early stages of diabetic retinopathy. That is why the American Optometric Association recommends that everyone with diabetes mellitus have a comprehensive dilated eye examination once a year. Early detection and treatment can limit the potential for significant vision loss from diabetic retinopathy.
Diabetes mellitus causes abnormal changes in the blood sugar (glucose) that your body ordinarily converts into energy to fuel different bodily functions.
Uncontrolled diabetes mellitus allows unusually high levels of blood sugar (hyperglycemia) to accumulate in blood vessels, causing damage that hampers or alters blood flow to your body's organs — including your eyes.
Diabetes mellitus generally is classified as two types:
Type 1 diabetes mellitus. Insulin is a natural hormone that helps regulate the levels of blood sugar needed to help "feed" your body. When you are diagnosed with type 1 diabetes mellitus, you are considered insulin-dependent because you will need injections or other medications to supply the insulin your body is unable to produce on its own. When you don't produce enough of your own insulin, your blood sugar is unregulated and levels are too high.
Type 2 diabetes mellitus. When you are diagnosed with type 2 diabetes mellitus, you generally are considered non-insulin-dependent or insulin-resistant. With this type of diabetes mellitus, you produce enough insulin but your body is unable to make proper use of it. Your body then compensates by producing even more insulin, which can cause an accompanying abnormal increase in blood sugar levels.
With both types of diabetes mellitus, abnormal spikes in blood sugar increase your risk of diabetic retinopathy.
Eye damage occurs when chronically high amounts of blood sugar begin to clog or damage blood vessels within the eye's retina, which contains light-sensitive cells (photoreceptors) necessary for good vision.
Prior studies had also assumed a clear glycemic threshold between people at high and low risk of diabetic retinopathy. However, it has been shown that the widely accepted WHO and American Diabetes Association diagnostic cutoff for diabetes mellitus of a fasting plasma glucose = 7.0 mmol/l (126 mg/dl) does not accurately identify diabetic retinopathy among patients. The cohort study included a multi-ethnic, cross-sectional adult population sample in the US, as well as two cross-sectional adult populations in Australia. For the US-based component of the study, the sensitivity was 34.7% and specificity was 86.6%. For patients at similar risk to those in this study (15.8% had diabetic retinopathy), this leads to a positive predictive value of 32.7% and negative predictive value of 87.6%.
Published rates vary between trials, the proposed explanation being differences in study methods and reporting of prevalence rather than incidence values.
During pregnancy, diabetic retinopathy may also be a problem for women with diabetes mellitus. It is recommended that all pregnant women with diabetes mellitus have dilated eye examinations each trimester to protect their vision.
People with Down's syndrome, who have three copies of chromosome 21, almost never acquire diabetic retinopathy. This protection appears to be due to the elevated levels of endostatin,[12] an anti-angiogenic protein, derived from collagen XVIII. The collagen XVIII gene is located on chromosome 21.
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:
Although these treatments are very successful (in slowing or stopping further vision loss), they do not cure diabetic retinopathy. Caution should be exercised in treatment with laser surgery since it causes a loss of retinal tissue. It is often more prudent to inject triamcinolone or Anti-VEGF. In some patients it results in a marked increase of vision, especially if there is an edema of the macula.
Avoiding tobacco use and correction of associated hypertension are important therapeutic measures in the management of diabetic retinopathy.
The best way of addressing diabetic retinopathy is to monitor it vigilantly and achieve euglycemia.
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 mellitus 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. During a vitrectomy, blood is removed from the center of your eye.
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.
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.
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.
Are scatter laser treatment and vitrectomy effective in treating proliferative retinopathy?
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.
What can I do if I already have lost some vision from diabetic retinopathy?
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.
Non-proliferative diabetic retinopathy (NPDR). This early stage of DR — identified by deposits forming in the retina — can occur at any time after the onset of diabetes mellitus.
Often no visual symptoms are present, but examination of the retina can reveal tiny dot and blot hemorrhages known as microaneurysms, which are a type of out-pouching of tiny blood vessels.
In type 1 diabetes mellitus, these early symptoms rarely are present earlier than three to four years after diagnosis. In type 2 diabetes mellitus, NPDR can be present even upon diagnosis.
Proliferative diabetic retinopathy (PDR). Of the diabetic eye diseases, proliferative diabetic retinopathy has the greatest risk of visual loss.
The condition is characterized by these signs:
These abnormal blood vessels formed from neovascularization tend to break and bleed into the vitreous humor of the eye. Besides sudden vision loss, more permanent complications can include tractional retinal detachment and neovascular glaucoma.
Macular edema may occur separately from or in addition to NPDR or PDR.
You should be monitored regularly, but you typically don't require laser treatment for diabetic eye disease until the condition is advanced.
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.
Stages of diabetic retinopathy
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.
Symptoms of diabetic retinopathy
- Seeing spots or floaters in your field of vision
- Blurred vision
- Having a dark or empty spot in the center of your vision
- Difficulty seeing well at night
Often there are no visual symptoms in the early stages of diabetic retinopathy. That is why the American Optometric Association recommends that everyone with diabetes mellitus have a comprehensive dilated eye examination once a year. Early detection and treatment can limit the potential for significant vision loss from diabetic retinopathy.
Causes of Diabetic Retinopathy
Diabetes mellitus causes abnormal changes in the blood sugar (glucose) that your body ordinarily converts into energy to fuel different bodily functions.
Uncontrolled diabetes mellitus allows unusually high levels of blood sugar (hyperglycemia) to accumulate in blood vessels, causing damage that hampers or alters blood flow to your body's organs — including your eyes.
Diabetes mellitus generally is classified as two types:
Type 1 diabetes mellitus. Insulin is a natural hormone that helps regulate the levels of blood sugar needed to help "feed" your body. When you are diagnosed with type 1 diabetes mellitus, you are considered insulin-dependent because you will need injections or other medications to supply the insulin your body is unable to produce on its own. When you don't produce enough of your own insulin, your blood sugar is unregulated and levels are too high.
Type 2 diabetes mellitus. When you are diagnosed with type 2 diabetes mellitus, you generally are considered non-insulin-dependent or insulin-resistant. With this type of diabetes mellitus, you produce enough insulin but your body is unable to make proper use of it. Your body then compensates by producing even more insulin, which can cause an accompanying abnormal increase in blood sugar levels.
With both types of diabetes mellitus, abnormal spikes in blood sugar increase your risk of diabetic retinopathy.
Eye damage occurs when chronically high amounts of blood sugar begin to clog or damage blood vessels within the eye's retina, which contains light-sensitive cells (photoreceptors) necessary for good vision.
Risk factors of diabetic retinopathy
All people with diabetes mellitus are at risk – those with Type 1diabetes mellitus(juvenile onset) and those with Type 2 diabetes mellitus (adult onset). The longer a person has diabetes mellitus, the higher the risk of developing some ocular problem. Between 40 to 45 percent of Americans diagnosed with diabetes mellitus have some stage of diabetic retinopathy. After 20 years of diabetes mellitus, nearly all patients with Type I diabetes mellitus and >60% of patients with Type II diabetes mellitus have some degree of retinopathy; however, these statistics were published in 2002Prior studies had also assumed a clear glycemic threshold between people at high and low risk of diabetic retinopathy. However, it has been shown that the widely accepted WHO and American Diabetes Association diagnostic cutoff for diabetes mellitus of a fasting plasma glucose = 7.0 mmol/l (126 mg/dl) does not accurately identify diabetic retinopathy among patients. The cohort study included a multi-ethnic, cross-sectional adult population sample in the US, as well as two cross-sectional adult populations in Australia. For the US-based component of the study, the sensitivity was 34.7% and specificity was 86.6%. For patients at similar risk to those in this study (15.8% had diabetic retinopathy), this leads to a positive predictive value of 32.7% and negative predictive value of 87.6%.
Published rates vary between trials, the proposed explanation being differences in study methods and reporting of prevalence rather than incidence values.
During pregnancy, diabetic retinopathy may also be a problem for women with diabetes mellitus. It is recommended that all pregnant women with diabetes mellitus have dilated eye examinations each trimester to protect their vision.
People with Down's syndrome, who have three copies of chromosome 21, almost never acquire diabetic retinopathy. This protection appears to be due to the elevated levels of endostatin,[12] an anti-angiogenic protein, derived from collagen XVIII. The collagen XVIII gene is located on chromosome 21.
Diagnosis of diabetic retinopathy
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.
Management of Diabetic Retinopathy
There are three major treatments for diabetic retinopathy, which are very effective[citation in reducing vision loss from this disease. In fact, even people with advanced retinopathy have a 90 percent chance of keeping their vision when they get treatment before the retina is severely damaged. These three treatments are laser surgery, injection of corticosteroids or Anti-VEGF into the eye, and vitrectomy.Although these treatments are very successful (in slowing or stopping further vision loss), they do not cure diabetic retinopathy. Caution should be exercised in treatment with laser surgery since it causes a loss of retinal tissue. It is often more prudent to inject triamcinolone or Anti-VEGF. In some patients it results in a marked increase of vision, especially if there is an edema of the macula.
Avoiding tobacco use and correction of associated hypertension are important therapeutic measures in the management of diabetic retinopathy.
The best way of addressing diabetic retinopathy is to monitor it vigilantly and achieve euglycemia.
Treatment for Diabetic Retinopathy
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 mellitus 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. During a vitrectomy, blood is removed from the center of your eye.
Treatment of macular edema
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.
What happens during laser treatment?
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.
What is a vitrectomy?
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.
Are scatter laser treatment and vitrectomy effective in treating proliferative retinopathy?
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.
What can I do if I already have lost some vision from diabetic retinopathy?
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.
Preventing Diabetic Retinopathy
If you want to avoid diabetic retinopathy or control its progress, try these tips:- Keep blood sugar within normal limits.
- Monitor blood pressure and keep it under good control.
- Maintain a healthy diet.
- Exercise regularly.
- Don't smoke.
- Follow your doctor's instructions to the letter.
- Above all, make sure you have regular eye exams!
Non-proliferative diabetic retinopathy (NPDR). This early stage of DR — identified by deposits forming in the retina — can occur at any time after the onset of diabetes mellitus.
Often no visual symptoms are present, but examination of the retina can reveal tiny dot and blot hemorrhages known as microaneurysms, which are a type of out-pouching of tiny blood vessels.
In type 1 diabetes mellitus, these early symptoms rarely are present earlier than three to four years after diagnosis. In type 2 diabetes mellitus, NPDR can be present even upon diagnosis.
Proliferative diabetic retinopathy (PDR). Of the diabetic eye diseases, proliferative diabetic retinopathy has the greatest risk of visual loss.
The condition is characterized by these signs:
- Development of abnormal blood vessels (neovascularization) on or adjacent to the optic nerve and vitreous.
- Pre-retinal hemorrhage, which occurs in the vitreous humor or front of the retina.
- Ischemia from decreased or blocked blood flow, with accompanying lack of oxygen needed for a healthy retina.
These abnormal blood vessels formed from neovascularization tend to break and bleed into the vitreous humor of the eye. Besides sudden vision loss, more permanent complications can include tractional retinal detachment and neovascular glaucoma.
Macular edema may occur separately from or in addition to NPDR or PDR.
You should be monitored regularly, but you typically don't require laser treatment for diabetic eye disease until the condition is advanced.
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