Diabetic Retinopathy is a complication of diabetes and is caused by
changes in the blood vessels of the retina that can bring about severe
loss of vision. Diabetic Retinopathy is the leading cause of new blindness
among adults in the United States, and people with untreated diabetes
are said to be 25 times more prone to blindness than the general population.
However, with improved methods of diagnosis and treatment only a small
percentage of those who develop Retinopathy experience serious problems
with vision. Therefore, it is important that individuals with diabetes
receive medical eye exams on an annual basis. In order to understand Diabetic
Retinopathy, it is helpful to first understand the basics of how the eye
How the eye works
The retina is a thin layer of tissue which covers
the back inside wall of the eye. The retina is like the film in a camera.
It is the seeing tissue of the eye. The cornea, pupil and lens of the
eye are clear and allow light to pass through. The light also passes through
the large space in the center of the eye called the vitreous cavity.
The vitreous cavity is filled with a clear, jelly-like substance called
vitreous or vitreous gel. The light is then focused on the retina. When
focused light hits the retina, a picture is taken. Messages about this
picture are sent to the brain through the optic nerve. This is how we
There are two kinds of Diabetic Retinopathy
In Diabetic Retinopathy the blood vessels of the retina become abnormal
and cause the problems that diabetic patients have with their eyesight.
Normally blood vessels in the retina do not leak. But with diabetes, the
retinal blood vessels can develop tiny leaks. These leaks cause fluid
or blood to seep into the retina. The retina then becomes wet and swollen
and cannot work properly. The form of Diabetic Retinopathy caused by leakage
of the retinal blood vessels is called Background Diabetic Retinopathy.
Another problem with the retinal blood vessels in diabetes is that they
can close. The retinal tissue, which depends on those vessels for nutrition,
will no longer work properly. The areas of the retina in which the blood
vessels have closed then foster the growth of abnormal new blood vessels
that can be very bad for the eye because they can cause bleeding and scar
tissue that can result in a total loss of vision. This form of Diabetic
Retinopathy is called Proliferative Diabetic Retinopathy.
Detection and Diagnosis
A comprehensive medical eye examination and appropriate treatment by an
Ophthalmologist is the best protection against eye damage due to Diabetic
Retinopathy. Serious Retinopathy can be present without symptoms and improve
with treatment. Therefore, people with diabetes should be aware of the
risks of developing visual problems and should have their eyes examined
regularly. Periodic eye examinations are also advisable for apparently
healthy people, because such examinations help detect the presence of
diabetes and other diseases. To detect Diabetic Retinopathy, the Ophthalmologist
dilates the pupils with eye drops and conducts a painless examination
of the inner part of the eye using an instrument called an ophthalmoscope.
If one or our doctors diagnoses Diabetic Retinopathy and feels that laser
treatment might be helpful, a special test called fluorescein angiography
may be done. To perform this test, dye is injected into a vein in the
patient's arm. The dye travels throughout the body, including the eyes.
With a special camera and a flash, a series of photographs of the retina
is taken as the dye passes through it. The photographs will show what
kinds of changes have occurred in the retina. Fluorescein angiography
is necessary for the doctor to establish the level of Retinopathy and
decide if the patient would benefit by laser treatment . The photographs
will provide a kind of map which the doctor will use as a guide to the
exact location and amount of laser treatment.
The best treatment for Diabetic Retinopathy is prevention by control of
diabetic disease. It is well known that patients whose A1C Hemoglobin
never exceeds 7.0 will seldom show any Retinopathy. When Diabetic Retinopathy
is diagnosed, the Ophthalmologist considers the patient's age, history,
lifestyle, and the degree of damage to the retina before deciding on the
most appropriate treatment or if further observation of the disease is
advised. In many cases treatment is not necessary; in others it is recommended
to halt the damage of Diabetic Retinopathy and improve sight wherever
Laser surgery can be very helpful for the treatment of the Diabetic Retinopathy.
The laser beam is a high-energy light that turns to heat when it is focused
on the parts of the retina to be treated. In Diabetic Retinopathy, the
laser heat either seals the leaking blood vessels of the macula or reduces
their leakage and allows the macula to dry. In Diabetic Retinopathy, the
laser destroys the diseased portions of the retina to stop the growth
of new blood vessels. In both cases, laser treatment may not always be
best or even possible. The decision to use laser depends mostly on the
type of Diabetic Retinopathy, its severity, and a judgment regarding how
well it may respond to such treatment. The doctor considers whether treating
an eye with laser is more likely to prevent further visual loss over no
treatment at all. Laser treatment may not always help. Even with laser
treatment, patients may continue to lose vision. Because diabetes is a
condition for which there is no cure, the diabetes may continue to damage
the retina unless excellent control of the disease is practiced by the