• Diabetic macular edema (DME) can be categorized as center-involved or non-center-involved
• Center-involved DME affects your direct line of focus
• Center-involved DME is treated more actively than non-center-involved DME

If you’ve been diagnosed with diabetic macular edema — fluid buildup and swelling in the central part of your retina — your doctor has likely told you whether you have center-involved or non-center-involved DME. Being diagnosed with one of these conditions will likely bring up questions about how they differ, how each one can affect you, and what types of treatment are available.

This article will cover differences and treatments for center-involved and non-center-involved DME.

Diabetic Macular Edema

DME is a condition that affects the retina, the tissue in the back of the eye responsible for your sight. The retina contains specialized cells that respond to light and send those signals to your brain. These specialized cells are highly concentrated in an area of the retina called the macula. Within the macula, the highest concentration of cells responsible for visual acuity (sharpness) is in the fovea area — the central part of the macula. “Macular edema” means swelling of the macula.

In individuals with type 2 diabetes, vision problems are relatively common. Up to 7 percent of people with diabetes develop DME. Even more common is a condition called diabetic retinopathy, a condition that causes damage to the retina. Diabetic retinopathy can lead to macular edema, so catching it early is essential.

Diabetic retinopathy develops when high blood glucose (sugar) levels lead to leakage in the capillaries (small blood vessels) of the retina. This leakage includes lipids (fats) and chemicals. One of the chemicals is called vascular endothelial growth factor (VEGF), which can lead to the formation of new, abnormal blood vessels and more swelling in the area. Treatments for diabetic retinopathy and DME often include medicines that block VEGF activity. This is called anti-VEGF therapy.

The retina can also release inflammatory chemicals due to an overactive immune response. Some treatments target these chemicals.

Center-Involved vs. Non-Center-Involved DME: What’s the Difference?

The terms “center-involved” and “non-center-involved” refer to where in the macula swelling is occurring in DME. An ophthalmologist (eye doctor) can diagnose both using optical coherence tomography (OCT). This is a noninvasive procedure that can provide high-resolution, 3D images of your retina. From OCT images, your eye doctor will be able to determine your retinal thickness and macular thickness in different areas.

Center-Involved DME

As the name suggests, center-involved DME involves swelling in the fovea. This area of the retina has the highest number of cells that send signals to the brain. The fovea is responsible for your sight that is in your direct line of focus. Swelling here will result in noticeable vision loss.

For a diagnosis of center-involved DME, you need to have increased foveal thickness. This is also sometimes called central subfield thickness.

Non-Center-Involved DME

This type of DME involves swelling in the macula but outside of the fovea. While this condition can still lead to vision loss — especially in the periphery — it does not affect your ability to focus on an object. This type of DME tends to have less effect on quality of life compared to center-involved DME.

Key Differences

The major differences between center-involved and non-center-involved DME are:

• Symptoms
• Quality of life
• Progression of condition
• Treatment and management regimens

Center-involved DME affects the fovea — the area most responsible for your focused sight. Therefore, swelling in this region needs immediate attention. This can affect your direct line of vision and make it hard to complete everyday tasks such as driving. Non-center-involved DME does not affect your direct line of sight as severely. This can make it more tolerable.

Most individuals with non-center-involved DME never progress to center-involved DME. People with non-center-involved DME may still have good visual acuity. Given that non-center-involved DME has less of an impact on quality of life than center-involved DME, the two conditions are managed and treated differently.

Managing Center-Involved vs. Non-Center-Involved DME

The same types of treatments are available for both center-involved and non-center-involved DME. In the case of center-involved DME, regular treatment is almost always recommended.

Managing Center-Involved DME

For center-involved DME, intravitreal injections are the standard of care. These are injections of medications into the eye. Several different medications can be delivered in this way, but the first choice of most doctors is some type of anti-VEGF therapy.

Steroids are another type of medication that can be delivered by intravitreal injection. These are synthetic hormones that counteract the effects of the inflammatory chemicals released into the retina. These medications are usually a doctor’s second choice for treatment. This is because they can have some negative side effects, such as causing cataracts — when the outside of the eye becomes cloudy.

Lastly, macular laser treatment — also known as laser photocoagulation — is another treatment option. This is used to close up blood vessels in the retina that may be leaking. Doctors used this treatment more commonly in the past, but it has more risks compared to anti-VEGF therapies. Now, it is recommended at low intensities for individuals who can’t take the other medications.

Many DiabetesTeam members have expressed worry about getting injections and laser treatments in the eye. “Does anyone have experience with laser/injections in the eyes for damage to the retina caused by weak and leaking blood vessels?” asked one member. “I’m nervous about the whole idea of injections into the eye.”

Other members who’ve had intravitreal injections have shared reassuring words about their experiences: “The injections were not a problem,” a member wrote. “They squirt a freezing drop in the eyeball. The injection is just a mere poke and doesn’t hurt. There were some side effects that I had to get used to, but they were gone after about two days.”

Managing Non-Center-Involved DME

For non-center involved, on the other hand, a “wait-and-see” management strategy may be the best course of action. This plan entails having regular checkups during which your eye doctor can see whether your condition has worsened and if treatment is necessary.

A clinical trial looked at vision deterioration in three groups of people with non-center-involved DME, all of whom had 20/25 vision or better. Members of one group were treated with anti-VEGF therapies, those in the second group underwent laser photocoagulation, and those in the third group didn’t receive any type of treatment — they were just observed. Over two years, there was no difference in visual acuity among each group. This means that observing was just as effective as the more invasive methods.

Intravitreal steroid injections are also not recommended for non-center-involved DME because the risk of cataracts may be greater than the benefit from the injection. This is especially true if your non-center-involved DME doesn’t directly influence your focused sight.

Macular laser treatment is not recommended for non-center-involved DME due to the risks. It has not shown to be particularly effective for non-center-involved DME.

If individuals wish to pursue treatment for non-center-involved DME, anti-VEGF treatment is often the best option for them.

Talk to Your Doctor

The best way to determine what type of DME you have is by talking to your doctor. Getting your eyes checked regularly and making your care team aware of new symptoms is important to detect eye changes in the early stages. With your unique health circumstances in mind, your doctor will be able to help you manage your DME effectively, thereby preventing further vision loss or maybe even repairing some you’ve already had.

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Have you been diagnosed with center-involved or non-center-involved DME? What type of treatment have you had? Share your experience in the comments below, or start a conversation by posting on your Activities page.