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DIABETIC RETINOPATHYDiabetic Retinopathy is the leading cause of loss of vision in the 20-64 year old age range. This potentially blinding condition affects the small blood vessels of the retina, the inside lining of the inside back of the eye. The eye is like a miniature camera. The cornea and lens are like the lenses of a camera.
The retina is like the film in a camera (Fig. 1). The
retina captures the picture (the object the eye is
looking at) and transmits the picture through the optic
nerve to the brain. The brain interprets the transmitted
picture. |
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Non-Proliferative Diabetic Retinopathy eventually
weakens the walls of the blood vessels which are normally present
in the retina. The blood vessel is a fluid conduit (like a garden
hose carrying water) which carries blood. Blood i.e., blood
components, and the fluid that carries these components (red
blood cells, white blood cells, etc.) normally stay inside the
blood vessel.
However, in Non-Proliferative Diabetic Retinopathy, the blood
vessel wall weakens, leaks fluid, and causes the retinal tissue
to become edematous (wet) (Fig. 2). This can be compared to a dry
sponge (normal retina) and a wet sponge (edematous or soggy
retina). The wet retina produces blurred vision when it affects
the macula-the part of the retina responsible for reading vision
(as compared to side or peripheral vision).
When the small blood vessels of the retina begin to
close off and quit carrying blood, the eye makes new blood
vessels in an attempt to replace those vessels which are not
working. The new blood vessels are known as neovascularization
(Fig. 3). This is Proliferative Diabetic Retinopathy, the second
form of Diabetic Retinopathy. Unfortunately, these vessels only
cause trouble. They are very fragile, easily break open, and
bleed. The bleeding can then fill the clear vitreous gel cavity
of the eye.
This prevents the retina from seeing what the eye is looking at. These abnormal blood vessels can also grow scar tissue which can pull on the retina causing retinal detachment and blindness.
The most important way to either prevent or slow
down the sight threatening complications of Diabetes
Mellitus is to strictly control the blood sugar and blood
pressure to normal levels all the time. However, even with
excellent control, eventually Diabetic Retinopathy will occur in
most diabetics if they have had the disease long enough. National
eye research studies have clearly demonstrated that laser surgery
can help to stabilize these eye complications. Vision (or further
loss of vision) can be stabilized in 50% to 60% of patients who
eventually need laser surgery intervention.
Fluorescein Angiography, a photographic study of retinal blood
flow, is extremely helpful in guiding laser surgery. For the
retinal edema in Non-Proliferative Diabetic Retinopathy, Laser
surgical applications are made specifically to the leaking areas
with care to avoid the macula itself (the reading vision area of
the retina) (Fig. 4).
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To treat the abnormal new blood vessel growth of
Proliferative Diabetic Retinopathy, Laser surgery
destroys that part of the retina no longer getting proper
blood supply thus indirectly destroying the abnormal
blood vessel growth (Fig. 5). If too much bleeding in the eye prevents laser surgery or if retinal detachment threatens vision (Fig. 6), vitrectomy surgery is performed. |
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Under microscopic control small instruments
literally cut and suction blood and scar tissue from inside the
eye to restore vision (Fig. 7).
It is very important for patients with Diabetes Mellitus to
have regular eye exams. Type I insulin dependent diabetics (onset
before age 30) should have yearly eye exams at least by the 5th
year after diagnosis and yearly thereafter. In this group of
patients sight threatening Diabetic Retinopathy rarely occurs
before four to five years in their disease. Type II diabetics
should have yearly exams from time of diagnosis of Diabetes
Mellitus. Diabetic pregnant women should have an eye exam every
three months during their pregnancy.
With excellent control of the blood sugar, blood pressure, and
with proper eye exams, most diabetic patients can enjoy good
vision all their lives. Until we find a cure for Diabetes
Mellitus, a true partnership of the patient and doctor is
critical for preservation of vision.
Diabetes and Hormone Center of the Pacific 1329 Lusitana Street, #304 Honolulu, HI 96813-2411 Tel: (808) 531-6886 Fax: (808) 523-5115
Your comments are welcomed. For medical
questions consult your physician.