What Is Diabetic Macular Edema?

Diabetic macular edema (DME) is a form of diabetic retinopathy where high blood glucose levels can cause leakage and swelling of the macula, a part of the eye responsible for sharp and detailed vision. Over time, damaged blood vessels leak fluid into the macula and cause blurry vision that could eventually lead to blindness. DME affects people with type 1 and type 2 diabetes.

Unfortunately, up to 75,000 new cases of DME develop each year in people with diabetes, and it is the leading cause of blindness among working-age Americans. However, there are now several treatment options available and everyone can take simple steps to help prevent or delay DME.

Often, the central vision of people with DME slowly declines over time, and there may be warning signs or symptoms (i.e., blurred vision, floaters, vision loss). Detecting DME early during a retina eye exam and before symptoms develop is the best way to prevent visual loss.

How can DME be prevented?

Although there are now more treatments available for DME, the best treatment is always prevention and close monitoring of blood pressure, blood sugars, and weight, although unfortunately this is not always a guarantee. Dr. Cooney illustrated the importance of lifestyle changes together with medical treatment by saying, “[if] you’re stepping on the gas pedal as I’m stepping on the brake, then we’re not going to get very far.”

Another issue has been the lack of awareness and education about DME among patients and providers. A recent survey of people with type 1 and type 2 diabetes from diabetic connect found that almost one in four people do not receive the recommended annual retina eye exam. More than half of those surveyed didn’t know DME is a leading cause of vision loss for people with diabetes, and many said they did not know they needed an exam or never talked to their health care provider about vision loss from diabetes.

Dr. Cooney pointed out that there is little communication between primary care physicians, endocrinologists, and ophthalmologists, and the current system must improve education and awareness of DME among providers as well as patients. Patients can request doctors to talk to each other, ask questions, be informed, and check on the status of their health and eye condition.

Three Key Tips for Preventing DME


Know the vital numbers: blood sugars, blood pressure, and weight.

2. Talk to a health care professional before there is a problem. The best way of preventing complications is being proactive about your risks and having a conversation with your provider before you experience symptoms.

3. Remember to have an annual retina (dilated) eye exam. The exam to check for DME is simple and involves checking vision, eye pressure, and dilating your eyes (which usually wears off after 4 hours). Dr. Cooney recommends everyone with diabetes get a dilated eye exam at least once a year.

What treatments are available for DME?

The standard treatment for diabetic macular edema for the past 25 years has been laser surgery, which seals up the leaking blood vessels to reduce the fluid around the macula.

The procedure can stop the progression of vision loss but cannot reverse damage that has already been done. In studies, laser surgery reduced the risk of moderate vision loss by 50% over three years, but the surgery can also be expensive and cause side effects.

Lucentis (ranibizumab) was approved by the FDA in August 2012, making it the first drug approved for diabetic macular edema. Lucentis is made by Roche’s Genentech and consists of once-monthly microinjections into the eye. The injection helps to decrease the leakiness of blood vessels, and clinical trials show that over two years, treatment with Lucentis allows individuals to read two additional lines on average on an eye chart – a significant improvement.

Avastin is a similar drug to Lucentis that has been approved for cancer treatment and is sometimes used “off-label” to treat DME if Lucentis is not available.

Over the past few years, research has started to focus on the use of anti-vascular endothelial growth factor (VEGF) therapy to treat DME. As new and promising treatment options emerge, these treatments will need to be reevaluated.

The benefits of individualized ranibizumab treatment for diabetic macular edema (DME) persist for at least three years, according to results from the RESTORE extension study.

The original RESTORE study showed that ranibizumab alone or combined with laser provided superior visual acuity gains when compared with laser monotherapy over 12 months in patients with visual impairment due to DME.
Source: American Society of Retina Specialists 2014
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