What is diabetic retinopathy?
Diabetic retinopathy is the most common
diabetic eye disease and a leading cause of blindness. It occurs due to changes
in the blood vessels of the retina. Retina is a thin layer of light sensitive
tissue at the back of the eye.
In
diabetes high blood glucose over a period of years causes damage to the small
blood vessels of the retina. These blood vessels develop microscopic cracks in
the vessel wall leading to outpouchings termed as microaneurysms. These
microaneurysms leak fluid into the retina.
Diabetes
also leads to closure of small blood vessels of the retina leading to reduced
blood supply to the retina. This leads to reduced vision as well as growth of
abnormal new vessels over the retina.
Normal view
View with diabetic retinopathy
What are the stages of diabetic retinopathy?
Two
stages have been noted.
Nonproliferative stage- In this stage there is damage
to the small blood vessels causing leakage of fluid into the retina. As a
result there can be swelling of the retinal tissue in places accompanied by
small dot like or flame shaped hemorrhages. There is also collection of protein
causing yellow spots in the retina called as hard exudates. This stage goes
through mild, moderate and severe stages. When these changes are seen in the
center of the retina known as the macula, it is termed as macular edema.
Macular edema can cause severe impairment of central vision.
Proliferative stage – In this stage there is growth
of abnormal new vessels on the retinal surface due to progressive blockage of
small blood vessels causing lack of blood supply and nutrition to the retina.
These new vessels can bleed into the cavity of the eye called as vitreous
cavity leading to vitreous hemorrhage. Severe vitreous hemorrhage can totally
block the vision. Eventually the new vessels develop into fibrotic membranes
which pull on the retina , distorting it and lifting it. This leads to severe
vision loss. This stage can also be accompanied by macular edema.
Macular edema
Nonprolifeartive retinopathy Proliferative retinopathy
Who is at risk for diabetic retinopathy?
All people with diabetes--both type
1 and type 2--are at risk. That's why everyone with diabetes should get a
comprehensive dilated eye exam at least once a year. The longer someone has
diabetes, the more likely he or she will get diabetic retinopathy. Between 40
to 45 percent of patients diagnosed with diabetes have some stage of diabetic
retinopathy. If you have diabetic retinopathy, your doctor can recommend
treatment to help prevent its progression.
During pregnancy, diabetic
retinopathy may be a problem for women with diabetes. To protect vision, every
pregnant woman with diabetes should have a comprehensive dilated eye exam as
soon as possible. Your doctor may recommend additional exams during your
pregnancy.
If you have diabetes get a
comprehensive dilated eye exam at least once a year and remember:
- Proliferative retinopathy can develop without symptoms. At this advanced stage, you are at high risk for vision loss.
- Macular edema can develop without symptoms at any stage of diabetic retinopathy.
- You can develop both proliferative retinopathy and macular edema and still see fine. However, you are at high risk for vision loss.
- Early detection and timely treatment can prevent vision loss.
If you have diabetic retinopathy,
you may need an eye exam more often. Regular follow up exams can preserve your
vision.
Keep your HbA1C levels below 7%.
This is a test that shows how good the diabetic control has been for the past
2-3 months in a patient. For most people, if your A1C is under 7%, it means
you’re doing a good job keeping the amount of sugar in your blood in your
target range.
The Diabetes Control and
Complications Trial (DCCT) showed that better control of blood sugar levels
slows the onset and progression of retinopathy. The people with diabetes who
kept their blood sugar levels as close to normal as possible also had much less
kidney and nerve disease. Better control also reduces the need for sight-saving
laser surgery.
Other studies have shown that
controlling elevated blood pressure and cholesterol can reduce the risk of
vision loss. Controlling these will help your overall health as well as help
protect your vision.
