About Diabetic Retinopathy
Diabetic retinopathy is a complication of diabetes mellitus. Diabetes damages the normal circulation of the body. That is why diabetics have problems with the circulation to their legs, kidneys, heart, brain and eyes.
In the early stage of diabetic retinopathy called Non Proliferative Diabetic Retinopathy (NPDR), Diabetes causes the blood vessels in the retina to leak and form deposits called exudates.
These leaky blood vessels create a complication called Macular Edema or retinal swelling, and are the most common cause of vision loss in diabetics. Macular Edema is diagnosed using fluorescein Angiography (FA) and Ocular Coherence Tomography (OCT).
The fluorescein Angiogram is a specialized type of retinal photography performed by first instilling drops in your eyes to dilate the pupil, then injecting a fluorescent dye, called Sodium fluorescein into a vein in your arm or hand, followed by taking a series of photographs of your retina in rapid succession. By observing the circulation of the fluorescent dye in the retina and the retinal blood vessels, it is possible to detect and observe "leaky" blood vessels or damaged vessels as well as where circulation in the retina may be compromised.
Ocular Coherence Tomography (OCT) is a method of high resolution digital imaging that allows clear cross sections of the retina and its layers to be directly observed, in much the same way as a CT scan allows us to observe high resolution images of other tissues and organs of your body.
Once identified, it is often possible to treat the swelling from Macular Edema using an intravitreal injection of a corticosteroid medication called Triamcinolone Actinomide or Kenalog.
If actual leaking vessels are identified, these leaking vessels can be treated by sealing them with Laser Photocoagulation Treatment to further resolve the swelling and prevent further vision loss. In the future, it is expected that there will be oral medication that can be taken to prevent the progression of moderate to severe nonproliferative diabetic retinopathy which is hoped to stabilize the diabetic eye disease. The first such oral medication for nonproliferative diabetic retinopathy will likely be a drug called Ruboxistaurin Mesylate which is to be marketed under the name Arxxant after it receives Food and Drug Administration (FDA) approval.
As the Diabetic Retinopathy advances, the normal retinal blood vessels begin to close, resulting in a condition called Retinal Ischemia. In this condition, the retina is now being deprived of sufficient oxygen and nourishment to maintain its normal health. In an effort to compensate for this lack of normal circulation, the retina begins to grow new abnormal blood vessels called neovascularization resulting in a condition called Proliferative Diabetic Retinopathy (PDR).
In Proliferative Diabetic Retinopathy (PDR), the abnormal vessels of neovascularization are quite fragile and if not treated aggressively will often lead to a severe loss of vision due to vitreous hemorrhaging, scar tissue formation, and finally retinal detachment. The abnormal blood vessel growth, neovascularization, can often be stopped with laser treatment or intravitreal injection of drugs called "anti-VEGF " compounds.
VEGF stands for "vascular endothelial growth factor" which is a substance produced that cause the chemical stimulation necessary to form these new blood vessels. By using an "anti-VEGF" drug it is possible to stop and actually cause the neovascularization to regress and vanish. The anti-VEGF drugs Avastin and Lucentis are both used as intravitreal injections with good results in managing proliferative diabetic retinopathy often along with laser photocoagulation treatment. It is possible to have extensive neovascularization still have excellent vision for some time. Thus if the neovascularization is not caught early enough and there is a vitreous hemorrage it is necessary to perform an eye surgery procedure called Vitrectomy whereby the vitreous is surgically removed.
It is critically important for diabetics to have a comprehensive eye exam at least once a year to evaluate the presence of retinopathy. It may be necessary to retinal photographs or fluorescein angiography on a regular basis to carefully document subtle changes in the retinal circulation. Early and aggressive treatment of diabetic retinopathy has been proven to be extremely successful in prolonging vision and preventing severe vision loss.
The overall maintenance of your health is important in maintaining your retinal circulation, as well as the circulation to your heart and kidneys. There is now considerable research that supports that controlling these health factors is critical as diabetic retinopathy seems to be an indicator of patients at risk for stroke. Researchers at the University of Melbourne in Australia reported in the March 2007 edition of the journal Stroke, that patients with diabetic retinopathy appear to have an increased risk of developing a stroke. They identified that the same factors causing damage to blood vessels in the Retina and causing diabetic retinopathy, also can be associated with an increased risk of stroke suggesting that patients with diabetic retinopathy also should be carefully monitored for the possibility of developing strokes.
All diabetics should work to lower their vascular risk factors, including not smoking, controlling hypertension, exercise, lowering cholesterol, eating a low fat diet and following your family physician's instructions carefully.
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