Retinopathy is the medical term for
damage to the tiny blood vessels (capillaries) that
nourish the retina, the tissue at the back of your
eye that captures light and relays information to
your brain. These blood vessels are often affected
by the high blood sugar levels associated with
Nearly half of people with known
some degree of diabetic retinopathy. The longer you
have diabetes, the more likely it is you'll develop
diabetic retinopathy. Initially, most people with
diabetic retinopathy experience only mild vision
problems. But the condition can worsen and threaten
your vision. Diabetic retinopathy is a leading cause
of legal blindness.
The threat of blindness is scary. But with early
detection and treatment, the risk of severe vision
loss from diabetic retinopathy is small. You can
take steps to protect your sight if you have
diabetes. These include a yearly eye examination and
steps to keep your blood sugar, blood pressure and
blood cholesterol under the best possible control.
Signs and symptoms
In the early, most treatable stages of diabetic retinopathy, you usually
experience no visual symptoms or pain. The disease can even progress to
an advanced stage without any noticeable change in your vision.
Symptoms of diabetic retinopathy may include:
"cobwebs" or tiny specks floating in your vision
Dark streaks or a
red film that blocks vision
Vision loss or
A dark or empty
spot in the center of your vision
Poor night vision
adjusting from bright light to dim light
If you have diabetes, your body doesn't use sugar (glucose) properly.
Sugar in your blood is vital to your health because it's a main source
of energy for your body's cells. But too much sugar in your blood can
cause damage throughout your body, including your kidneys, nerves, heart
and eyes. Damage to the capillaries in your eyes occurs in diabetic
Diabetic retinopathy occurs in two types, usually affecting both eyes
Nonproliferative diabetic retinopathy (NPDR).
This type, also called background diabetic retinopathy, is an early
stage of the disease. It's the most common type of retinopathy, and
symptoms are often mild or nonexistent.
In NPDR the walls
of blood vessels in the retina weaken. Tiny bulges called
microaneurysms (mi-kro-AN-u-riz-umz) protrude from the vessel walls.
Another term for these microaneurysms is outpouching. The
microaneurysms may begin to leak, oozing fluid and blood into the
retina. As NPDR progresses, other signs of damage appear. These
include patches of swollen nerve fibers, which are called
cotton-wool spots because they look like fluffy wisps of cotton.
Mild NPDR may not
affect your ability to see clearly. Vision problems from more severe
NPDR are usually the result of swelling (edema) of the central part
of the retina (macula) or the closing of capillaries, which reduces
blood flow to the macula (macular ischemia). When the macula can't
function properly, your central vision decreases.
diabetic retinopathy (PDR).
This is the more advanced form of the disease. Retinopathy becomes
proliferative when abnormal new blood vessels grow (proliferate) in
the retina or the optic nerve. The blood vessels also can grow into
the vitreous, the clear, jelly-like substance that fills the center
of your eye.
growth follows the widespread closing of capillaries in the retina
due to high blood sugar levels. The condition can cause vision loss
affecting both your central and peripheral vision. The new blood
vessels may leak blood into the vitreous, which clouds or even
blocks your vision. Other complications include detachment of the
retina due to scar tissue formation (traction retinal detachment)
and a form of glaucoma associated with the growth of abnormal blood
vessels on the iris, the pigmented portion of the eye surrounding
the pupil (neovascular glaucoma).
Blurred vision in diabetes
Blurred vision can be brought on by rapid fluctuations in blood sugar.
Prolonged periods of elevated blood sugar cause sugar and its breakdown
products to accumulate in the lens. This accumulation sucks up water and
makes the lens swell, resulting in nearsightedness — meaning distant
objects appear blurry. The nearsightedness subsides once your blood
sugar is brought under steady control.
Blurred vision can also be caused by macular swelling (edema),
regardless of your blood sugar level. This is cause for greater concern
because macular edema often develops in people with diabetic
retinopathy. The swelling may fluctuate during the day, making your
vision get better or worse. If blood vessels in your eye are
hemorrhaging, you might notice spots floating in your field of vision.
These small spots are often followed within a few days or weeks by
larger spots or clouds, which are caused by more marked hemorrhaging.
Having diabetes puts you at risk of retinopathy, whether you have type 1
diabetes or type 2 diabetes. Your risk increases the longer you have the
Other risk factors for diabetic retinopathy include: