Diabetic Macular Edema
Diabetes is the most common cause of blindness among working-aged people, and all people living with the disease should monitor their eye health carefully. Over time, diabetes can lead to diabetic retinopathy, which is damage to the blood vessels in the retina. As this damage continues, blood vessels in the retina begin to leak fluid.
This, in turn, can lead to a condition known as diabetic macular
edema, or DME, where fluid accumulates in the macula. Patients with DME
typically experience blurred vision which may progress to blindness.
- Diabetic Macular Edema (DME) affects up to 10% of all patients with diabetes1
- Up to 75,000 new cases occur every year1
- Up to 30% of patients with DME will experience moderate visual loss (doubling of the visual angle)1
There are two kinds of DME:
Focal DME is caused by tiny abnormalities in blood vessels, known as microaneurysms. These leaking microaneurysms can lead to vision loss.
Diffuse DME is caused by widening (dilation) of retinal capillaries (extremely thin, narrow blood vessels) throughout the back of the eye.
What are the symptoms?
All patients who suffer from diabetes have a risk of developing DME. The symptoms of DME can include:
- Blurred vision
- Double vision
- Floaters (small black dots or lines made up of cellular debris seen "floating" across the front of the eye) These floaters may temporarily interfere with vision. They are also linked with other eye diseases.
What are the causes?
DME is linked with the following:
- The degree of diabetic retinopathy (problems with blood vessels in the retina related to diabetes)
- The length of time a patient has had diabetes
- The type of diabetes each patient has (the milder the diabetes, the lower the incidence of DME)
- Severe hypertension (high blood pressure)
- Fluid retention
- Hypoalbuminemia (low protein in body fluids)
- Hyperlipidemia (high levels of fats in the blood)
Many of these conditions can make DME worse, but when they are treated and controlled, DME may get better.
How can it be treated?
Laser treatment for focal DME:
- Focal laser treatment may be used to treat focal DME.
- The goal of treatment is to close leaking microaneurysms to help maintain current vision and reduce progressive visual loss.
- The laser light is absorbed by the blood inside the microaneurysms using green and yellow wavelengths.
- Confirm closure at the end of the treatment session, and retreat if
Laser treatment for diffuse DME
- Grid laser treatment is used to treat diffuse DME.
- The goal of treatment is to produce a mild to moderately intense retinal burn to help maintain current vision and reduce progressive visual loss.
- A fluorescein angiogram may guide treatment.
- Three months after treatment the patient should be rechecked to make sure that the DME is responding to therapy.
- In 3-6 months, expect retinal thickening and hard exudates (concentrated areas of protein) to start to improve.
- The excess fluid that leads to edema (swelling) will begin to reabsorb into
the surrounding tissues.
- Eventually the bodily substances that create the hard exudates will be reabsorbed as well. Be aware that as the swelling begins to improve, hard exudates may increase temporarily in the eye. This is a sign of improvement, and the exudates will soon disappear.
- The reality is: even after successful treatment, some people do not
experience improved vision. However, if vision remains stable, continued
treatment could be beneficial.
1 Ali FA. A review of diabetic macular edema. http://www.djo.harvard.edu/meeei/OA/ME/ME.html. Accessed on the web on 7/26/02, 8:57 am.