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Diabetes
Diabetes mellitus
results when blood sugar levels stay too high due to an abnormal
decrease in insulin production, or when the insulin produced is
ineffective.
Ten percent of
diabetics are Type I (juvenile onset, insulin dependent), which begins
before age 35 and is caused by a destruction of the beta cells that
produce insulin. This can be caused by genetic factors, viral
infection of the pancreas, or an immune system gone awry. These
patients have to take insulin.
Type II diabetes (adult
onset) generally begins after age 35. Insulin levels may be normal but
the body does not use the insulin to maintain proper blood sugar
levels. The pancreas eventually decreases insulin production, making
the situation worse. Genetics and obesity are major factors. Treatment
involves diet control, exercise, and oral medications.
Types of diabetic eye disease
Cataracts
— Diabetics are twice as likely to develop cataracts and
they develop cataracts at an earlier age than non-diabetics.
Glaucoma
— Diabetics are twice as likely to develop glaucoma as the general
population.
Diabetic retinopathy —
This is a disease of the retinal blood vessels. It is thought
that hyperglycemia (increased levels of sugar in the blood) alters
retinal blood vessel metabolism. Blood platelets become
abnormally sticky and retinal blood vessels narrow. Diabetic retinopathy is
a leading cause of blindness.
According to the
National Institute of Health, the U.S. has 16 million diabetics, and
half of them have some stage of diabetic retinopathy. About 8%
of those with diabetic retinopathy have retinopathy at a vision loss
stage. Advanced diabetic retinopathy is the leading cause of
blindness among working age Americans, with 25,000 patients developing
blindness each year from the disease.
There are three
important risk factors for the development of vision threatening
diabetic retinopathy:
Type of diabetes —
Type I diabetics are more likely to develop diabetic retinopathy
than Type II diabetics.
Duration of diabetes —
The longer you have diabetes, the more likely you are to
develop serious diabetic retinopathy.
Blood sugar control —
Diabetics with poor control of their blood sugar levels are more
likely to develop significant diabetic retinopathy.
Almost all Type I
diabetics with diabetes for more than 15 years have diabetic
retinopathy. Type II diabetics who are on insulin and have had
diabetes for more than 20 years have a 50% chance of developing
proliferative diabetic retinopathy.
Once a diagnosis of diabetic retinopathy has been
made, the ophthalmologist may use the results and guidelines of
various studies to guide the treatment of the disease with laser
photocoagulation of the retina.
Most patients will
volunteer whether or not they are diabetic, but some do not. Ask
patients specifically if they are diabetic, or if their doctor
considers them to be a "borderline" diabetic.
The following are some
common non-insulin anti-diabetic drugs. Some patients who take
some of these drugs do not consider themselves to be diabetic.
Being aware of these drugs will tip you off to a patient with blood
sugar problems if they do not volunteer the information. Most of
these are common medications, and some are available in generic
form. Pay attention to the spelling of the generic as well as
the trade name so that you can spell the names correctly in the chart.
Amaryl
(glimepiride)
Diabeta
(glyburide)
Glucophage
(metformin)
Glucotrol
(glipizide)
Glynase
(glyburide)
Prandin
(repaglinide)
Precose
(acarbose)
Rezulin
(troglitazone)
The type of diabetes,
the duration of the disease, and blood sugar control are major risk
factors in the development of vision-threatening diabetic retinopathy.
The ophthalmologist will want to know the answer to the following
questions:
At what age were you
diagnosed with diabetes?
Do you take insulin?
How long have you been on insulin?
If the patient
doesn't take insulin: What medication do you take, or are you diet
controlled?
Is your blood sugar
under good control?
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