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There are two types of Diabetic
Retinopathy: Nonproliferative Diabetic
Retinopathy (NPDR) and Proliferative Diabetic
Retinopathy (PDR). NPDR, commonly known
as "Background Retinopathy," is an early
stage of Diabetic Retinopathy. In this
stage, tiny blood vessels within the retina
leak blood or fluid. The leaking fluid
causes the retina to swell or to form
deposits called exudates. Many people
with diabetes have mild NPDR, which usually
does not affect their vision. When vision
is affected it is the result of Macular
Edema and/or Macular Ischemia.
- Macular Edema is swelling,
or thickening, of the macula, a small
area in the center of the retina that
allows us to see fine details clearly.
The swelling is caused by fluid leaking
from retinal blood vessels. It is the
most common cease of visual loss in
diabetes. Vision loss may be mild to
severe, but even in the worst cases,
peripheral vision continue to function.
- Macular Ischemia occurs
when small blood vessels (capillaries)
close. Vision blurs because the macula
no longer receives sufficient blood
supply to work properly.
PDR is present when
abnormal new vessels (neovascularization)
begin growing on the surface of the retina
or optic nerve. The main cause of PDR
is widespread closure of retinal blood
vessels, preventing adequate blood flow.
The retina responds by growing new blood
vessels in an attempt to supply blood
to the area where the original vessels
closed. Unfortunately, the new, abnormal
blood vessels do not resupply the retina
with normal blood flow. The new vessels
are often accompanied by scar tissue that
may cause wrinkling or detachment of the
retina. PDR may cause more sever vision
loss than NPDR because it can affect both
central and peripheral vision. Proliferative
Diabetic Retinopathy causes visual loss
in the following ways: Vitreous Hemorrhage:
The fragile new vessels may bleed into
the vitreous, a clear jelly-like substance
that fills the center of the eye. If the
Vitreous Hemorrhage is small, a person
might see only a few new dark floaters.
A very large hemorrhage might block out
all vision. Vitreous Hemorrhage alone
does not cause permanent vision loss.
When the blood clears, visual acuity may
return to its former level unless the
macula is damaged. Traction Retinal Detachment:
When PDR is present, scar tissue associated
with neocavascularization can shrink,
wrinkling and pulling the retina from
its normal position. Macular wrinkling
can cause visual distortion. More severe
vision loss can occur if the macula or
large areas of the retina are detached.
Neovascular Glaucoma: Occasionally, extensive
retinal vessel closure will cause new,
abnormal blood vessels to grow on the
iris (colored part of the eye) and block
the normal flow of fluid out of the eye.
Pressure in the eye builds up, resulting
in Neovascular Glaucoma, a sever eye disease
that causes damage to the optic nerve.
How Is Diabetic Retinopathy
Treated?
The best treatment is to
prevent the development or retinopathy
as much as possible. Strict control of
your blood sugar will significantly reduce
the long-term risk of vision loss from
Diabetic Retinopathy. If high blood pressure
and kidney problems are present, they
need to be treated. Laser surgery is often
recommended for people with Macular Edema,
PDR and Neovascular Glaucoma.
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