Diabetic retinopathy is damage to the retina. This is the light-sensitive lining at the back of the eyeball. The condition
starts quietly and slowly. The only way to see changes is with a careful eye examination by an experienced ophthalmologist,
or by taking photographs of the retina. In its early and even late stages, retinopathy does not usually affect a person’s
ability to see. Once the vision starts to be affected, it suggests that the retinopathy is far advanced.
There are different stages of change.
Early changes
The earliest changes are called background retinopathy (non-proliferative retinopathy). This consists of little swellings of the blood vessels, called microaneurysms. They may start to leak or burst causing
leaking (exudates) and bleeding (hemorrhage). In cases where this is extensive, there may be a problem with vision in two
cases:
-
if the bleeding affects the part of the eye that focuses on an object (
macula)
-
if that area swells (
macular edema).
Almost everyone with type 1 diabetes will develop at least a small amount of background retinopathy after having the disease
for 15 to 20 years.
Later changes
The early stage of retinopathy may progress to proliferative retinopathy. In this stage, the eye begins to make new blood
vessels to provide better blood flow. These new vessels are fragile. They may cause bleeding and scarring in the fluid chambers
(vitreous body) in front of the retina. This bleeding is called vitreous hemorrhage. The scarring can cause the retina to
separate from the eye. Proliferative retinopathy and its effects are a major cause of partial or complete loss of sight.
In developed countries, diabetic retinopathy is the most common cause of adults becoming blind. However, this does not mean
that all or even most people with diabetes will lose their vision.
What can be done?
Researchers have made great strides in repairing vision and reducing the risk of blindness in people with diabetes. Photocoagulation
is a laser therapy technique that prevents blindness. It destroys abnormal blood vessels, repairs leaking ones, and stops
new ones from forming. This should reduce the risk of blindness by more than 75 to 80 percent. Occasionally, if the retina
has bled too much or has become detached, surgery may be needed.
Cataracts
A cataract is a thickening in the lens of the eye. Cataracts cause a blurring of vision. They are very rarely found in young
people with type 1 diabetes, but can develop at any time.
Cataracts can be removed in surgery. Any remaining sight problems can be corrected with glasses or contact lenses.
Glasses
Children with diabetes are no more likely than their non-diabetic friends to need glasses. Diabetes does not cause permanent
problems with sight unless retinopathy has become severe. This is very rare during childhood and adolescence. Sometimes,
rapid changes in blood sugar can cause changes to the lens of the eye. There can be swelling (if the sugar is very high) or
contraction (if the sugar is very low). This can cause temporary blurring of vision. Balancing the blood sugar will correct
this. Still, a child who complains of problems seeing the chalkboard, or who has to sit close to the television, should have
an eye exam to see if glasses are required.
