• Diabetic macular edema (DME) can be categorized as center-involved or non-center-involved.
• Center-involved DME affects central visio, whereas non-center-involved DME impacts peripheral or other areas of vision.
• 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 may raise questions about how they differ, how each one can affect you, and what types of treatment are available.

Here’s some information on the differences between center-involved and non-center-involved DME, along with their treatments, that you can discuss more with your doctor.

What Is 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 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 — the central part of the macula. “Macular edema” means “swelling of the macula,” which is what occurs in people with DME.

In individuals with type 2 diabetes, vision problems are relatively common. About 7 percent of people with diabetes develop DME. Even more common is 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 cause the retina’s capillaries (small blood vessels) to leak. This leakage includes lipids (fats) and naturally occurring proteins. A protein called vascular endothelial growth factor (VEGF) can lead to neovascularization (formation of new, abnormal blood vessels) and swelling in the area. Treatment of DME and diabetic retinopathy often includes anti-VEGF therapy — medicines that block VEGF activity.

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

Center-Involved vs. Non-Center-Involved Diabetic Macular Edema: What’s the Difference?

The terms “center-involved” and “non-center-involved” describe where swelling occurs in the macula for people with DME. An ophthalmologist (eye doctor) can diagnose both types using optical coherence tomography (OCT). This noninvasive procedure provided high-resolution images of your retina to detect retinal thickening. From OCT images, your eye doctor will be able to measure your macular thickness, which can indicate DME.

Center-Involved DME

As the name suggests, center-involved DME involves swelling in the fovea, which is in the center of the macula. This part of the macula 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 impairment.

Center-involved DME features swelling of the fovea, which is responsible for your sight that is in your direct line of focus.

For a diagnosis of center-involved DME, you need to have thickening in the fovea, known as central subfield thickness (CST). CST is a measurement of the center of the fovea, a circular area that’s 1 millimeter in diameter. Doctors use OCT imaging to measure CST in center-involved DME. However, some ophthalmology studies show that CST alone doesn’t correlate well with visual acuity, even though it’s a diagnostic tool for center-involved-DME. This suggests that other factors in the disease may contribute to vision loss.

Non-Center-Involved DME

This type of DME involves swelling in the macula but outside the fovea. Although this condition can still lead to vision loss, it doesn’t affect your ability to focus on an object directly in front of you. Non-center-involved 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
• Treatment and management regimens

Center-involved DME affects the fovea, the area most responsible for your focused sight, and swelling in this region needs immediate attention. It can affect your direct line of vision and make it hard to complete everyday tasks such as driving or reading. Non-center-involved DME doesn’t affect your direct line of sight as severely, so it can be more tolerable.

Center-involved DME can make it hard to complete everyday tasks such as driving or reading.

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 impact on quality of life than center-involved DME does, the two conditions are managed differently.

Managing Center-Involved vs. Non-Center-Involved Diabetic Macular Edema

The same types of treatments are available for both center-involved and non-center-involved DME. For center-involved DME, treatment is almost always recommended to help prevent central vision loss.

Managing Center-Involved DME

For center-involved DME, intravitreal injections are the standard of care. These are injections of medications into the eye. Most doctors usually first choose a type of anti-VEGF therapy, such as:

• Aflibercept (Eylea)
• Bevacizumab (Avastin)
• Faricimab-svoa (Vabysmo)
• Ranibizumab (Lucentis)

Steroids are another type of medication that can be delivered by intravitreal injection. These synthetic hormones counteract the effects of inflammation in the retina and are usually a doctor’s second choice for treatment. This is because they can have some negative side effects, such as causing cataracts and glaucoma.

Most individuals with non-center-involved DME never progress to center-involved DME.

Macular laser treatment — also known as laser photocoagulation — is another option. This treatment is used to close blood vessels in the retina that may be leaking. Doctors used laser therapy more often in the past, but it has certain risks compared with anti-VEGF agents. Now it’s sometimes recommended for individuals who can’t tolerate 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?” one member asked. “I’m nervous about the whole idea of injections into the eye.”

Other members who’ve had intravitreal injections shared reassuring words: “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 DME, on the other hand, a “wait-and-see” management strategy may be best. This plan entails regular checkups so your eye doctor can see if your condition has worsened and treatment is necessary.

A randomized 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 treatment, those in the second group underwent laser photocoagulation, and those in the third group didn’t receive any treatment — they were just observed. Over two years, there was no difference in visual acuity among each group. This suggests that observing non-center-involved DME may be just as effective as more invasive treatments.

Intravitreal corticosteroid injections also are not recommended for non-center-involved DME because the risks of cataracts and glaucoma may outweigh the benefits of the injection. This is especially true if non-center-involved DME doesn’t directly influence your focused sight.

Macular laser treatment isn’t recommended for center-involved DME due to the risks, and it hasn’t been shown to be particularly effective for non-center-involved DME. Anti-VEGF injections are often the best option for people who want to pursue treatment for center-involved DME.

Talk to Your Doctor

If you’re living with type 2 diabetes, be sure to talk with your health care provider about your risks of developing DME. Always report any new vision problems to your diabetes care team. Having regular eye exams can help protect your vision by detecting eye changes in the early stages. If you develop DME, your doctor can help you manage it with appropriate treatment and follow-up monitoring.

Find Your Team

DiabetesTeam is the social network for people with diabetes and their loved ones. On DiabetesTeam, more than 158,000 members come together to ask questions, give advice, and share their stories with others who understand life with diabetes.

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