Diabetic Retinopathy

 

Diabetic Retinopathy

Definition

Diabetic retinopathy is a serious complication of diabetes, blood vessels swell and leak into the retina, which then damaged.

 

Organ

In case of diabetic retinopathy, lesions are present on the retina.

 

Symptoms

You can have diabetic retinopathy and not be aware of it, since the early stages of diabetic retinopathy often don't have symptoms.

As the disease progresses, diabetic retinopathy symptoms may include:

  • Spots, dots or cobweb-like dark strings floating in your vision (called floaters);
  • Blurred vision;
  • Vision that changes periodically from blurry to clear;
  • Blank or dark areas in your field of vision;
  • Poor night vision;
  • Colors appear washed out or different;
  • Vision loss.

Diabetic retinopathy symptoms usually affect both eyes.

Source : AAO 

 

Frequency

Diabetic retinopathy is the most common cause of vision loss among people with diabetes and a leading cause of blindness among working-age adults.

Source : National Eye Institute 

The most common and potentially most blinding of these complications, however, is diabetic retinopathy, which is, in fact, the leading cause of new blindness in persons aged 25-74 years in the United States. Approximately 700,000 persons in the United States have proliferative diabetic retinopathy, with an annual incidence of 65,000. An estimate of the prevalence of diabetic retinopathy in the United States showed a high prevalence of 28.5% among those with diabetes aged 40 years or older.

Source : Emedicine

 

Causes

Diabetes mellitus (DM) causes abnormal changes in the blood sugar (glucose) that your body ordinarily converts into energy to fuel different bodily functions.

Uncontrolled diabetes 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 generally is classified as two types:

Type 1 diabetes. 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, 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. When you are diagnosed with type 2 diabetes, you generally are considered non-insulin-dependent or insulin-resistant. With this type of diabetes, 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, 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.

Source : All About Vision

 

Evolution

Without prompt treatment, bleeding often recurs, increasing the risk of permanent vision loss. If DME occurs, it can cause blurred vision.

Source : National Eye Institute 

 

Prevention

There are steps you can take to reduce your chance of vision loss from diabetic retinopathy and its complications:

Control your blood sugar levels. Keep blood sugar levels in a target range by eating a healthful diet, frequently monitoring your blood sugar levels, getting regular physical exercise, and taking insulin or medicines for type 2 diabetes if prescribed.

Control your blood pressure. Retinopathy is more likely to progress to the severe form and macular edema is more likely to occur in people who have high blood pressure. It is not clear whether treating high blood pressure can directly affect long-term vision. But in general, keeping blood pressure levels in a target range can reduce the risk of many different complications of diabetes. For more information about how to control your blood pressure, see the topic High Blood Pressure.

Have your eyes examined by an eye specialist (ophthalmologist or optometrist) every year. Screening for diabetic retinopathy and other eye problems will not prevent diabetic eye disease. But it can help you avoid vision loss by allowing for early detection and treatment.

See an ophthalmologist if you have changes in your vision. Changes in vision-such as floaters, pain or pressure in the eye, blurry or double vision, or new vision loss-may be symptoms of serious damage to your retina. In most cases, the sooner the problem can be treated, the more effective the treatment will be.

 

The risk for severe retinopathy and vision loss may be even less if you:

Don't smoke. Although smoking has not been proved to increase the risk of retinopathy, smoking may aggravate many of the other health problems faced by people with diabetes, including disease of the small blood vessels.

Avoid hazardous activities. Certain physical activities, like weight lifting or some contact sports, may trigger bleeding in the eye through impact or increased pressure. Avoiding these activities when you have diabetic retinopathy can help reduce the risk of damage to your vision.

Get adequate exercise. Exercise helps keep blood sugar levels in a target range, which can reduce the risk of vision damage from diabetic retinopathy. Talk to your doctor about what kinds of exercise are safe for you.

Source : WebMD 

 

Diagnosis

Diabetic retinopathy and DME are detected during a comprehensive dilated eye exam that includes:

  • Visual acuity testing. This eye chart test measures a person’s ability to see at various distances.
  • Tonometry. This test measures pressure inside the eye.
  • Pupil dilation. Drops placed on the eye’s surface dilate (widen) the pupil, allowing a physician to examine the retina and optic nerve.
  • Optical coherence tomography (OCT). This technique is similar to ultrasound but uses light waves instead of sound waves to capture images of tissues inside the body. OCT provides detailed images of tissues that can be penetrated by light, such as the eye.

 

A comprehensive dilated eye exam allows the doctor to check the retina for:

  • Changes to blood vessels
  • Leaking blood vessels or warning signs of leaky blood vessels, such as fatty deposits
  • Swelling of the macula (DME)
  • Changes in the lens
  • Damage to nerve tissue

If DME or severe diabetic retinopathy is suspected, a fluorescein angiogram may be used to look for damaged or leaky blood vessels. In this test, a fluorescent dye is injected into the bloodstream, often into an arm vein. Pictures of the retinal blood vessels are taken as the dye reaches the eye.

Source : National Eye Institute

 

Treatment

DME can be treated with several therapies that may be used alone or in combination.

Anti-VEGF Injection Therapy. Anti-VEGF drugs are injected into the vitreous gel to block a protein called vascular endothelial growth factor (VEGF), which can stimulate abnormal blood vessels to grow and leak fluid. Blocking VEGF can reverse abnormal blood vessel growth and decrease fluid in the retina. Available anti-VEGF drugs include Avastin (bevacizumab), Lucentis (ranibizumab), and Eylea (aflibercept). Lucentis and Eylea are approved by the U.S. Food and Drug Administration (FDA) for treating DME. Avastin was approved by the FDA to treat cancer, but is commonly used to treat eye conditions, including DME.

The NEI-sponsored Diabetic Retinopathy Clinical Research Network compared Avastin, Lucentis, and Eylea in a clinical trial. The study found all three drugs to be safe and effective for treating most people with DME. Patients who started the trial with 20/40 or better vision experienced similar improvements in vision no matter which of the three drugs they were given. However, patients who started the trial with 20/50 or worse vision had greater improvements in vision with Eylea.

Most people require monthly anti-VEGF injections for the first six months of treatment. Thereafter, injections are needed less often: typically three to four during the second six months of treatment, about four during the second year of treatment, two in the third year, one in the fourth year, and none in the fifth year. Dilated eye exams may be needed less often as the disease stabilizes.

Avastin, Lucentis, and Eylea vary in cost and in how often they need to be injected, so patients may wish to discuss these issues with an eye care professional.

 

Focal/grid macular laser surgery. In focal/grid macular laser surgery, a few to hundreds of small laser burns are made to leaking blood vessels in areas of edema near the center of the macula. Laser burns for DME slow the leakage of fluid, reducing swelling in the retina. The procedure is usually completed in one session, but some people may need more than one treatment. Focal/grid laser is sometimes applied before anti-VEGF injections, sometimes on the same day or a few days after an anti-VEGF injection, and sometimes only when DME fails to improve adequately after six months of anti-VEGF therapy.

Corticosteroids. Corticosteroids, either injected or implanted into the eye, may be used alone or in combination with other drugs or laser surgery to treat DME. The Ozurdex (dexamethasone) implant is for short-term use, while the Iluvien (fluocinolone acetonide) implant is longer lasting. Both are biodegradable and release a sustained dose of corticosteroids to suppress DME. Corticosteroid use in the eye increases the risk of cataract and glaucoma. DME patients who use corticosteroids should be monitored for increased pressure in the eye and glaucoma.

Source : National Eye Institute

 

Images

  Normal vision

Eye disease simulation, normal vision

SourceBy National Eye Institute, National Institutes of Health [Public domain], via Wikimedia Commons

The same view with diabetic retinopathy

 Eye disease simulation, diabetic retinopathy

SourceBy National Eye Institute, National Institutes of Health [Public domain], via Wikimedia Commons

 

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