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Causes,
Incidence and Risk Factors
Diabetes is characterized by excessively high levels of glucose (blood
sugar) in the blood, resulting from the body's inability to properly utilize
certain food elements like sugar and starches
Diabetes
manifests itself throughout the body and can cause kidney failure, heart
disease, and blindness. While diabetes can affect many parts of the eye,
its mostcommon manifestation takes the form of diabetic retinopathy.
Diabetic
retinopathy affects the retina, the light-sensitive tissue that lines
the eye's back wall. There are two forms of the disease; nonproliferative
(or background) retinopathy and proliferative retinopathy. Background
retinopathy can be a precursor to the more serious proliferative retinopathy.
With background retinopathy, the blood vessels in the retina change in
diameter -- some shrink and others swell. This disturbs blood flow in
the retina; it may lead to hemorrhaging or to restriction of vital blood
supply in other areas. This condition is usually not sight-threatening,
but it can be a warning sign of further damage and should be monitored
carefully. Fortunately, in about 60% of diabetic patients with background
retinopathy, the condition does not worsen.
Proliferative
retinopathy begins when areas of the retina no longer receive sufficient
blood supply. The blood-starved tissue then produces molecules that stimulate
the growth of new vessels near the surface of the retina. These delicate
vessels can break and leak blood into the vitreous, the clear fluid that
fills the eye's main chamber. When the vitreous is clouded, light cannot
pass through to the retina and images become either distorted or blocked.
Retinal detachment may occur if the scar tissue that forms around the
leaking blood vessels pulls the retina away from the back wall of the
eye. In addition, other eye problems like glaucoma can occur with severe
cases of diabetic retinopathy.
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