Diabetic Macular Edema: Everything You Need To Know
Key takeaways:
- Diabetic macular edema is a diabetes-related eye complication caused by prolonged high blood sugar levels over a long period of time.
- DME can affect anyone with diabetes and cause symptoms like blurry vision and vision loss.
- Regular screening through dilated eye exams is critical for prevention and early treatment.
People with diabetes are at higher risk for diabetic macular edema (DME), a common complication of diabetic retinopathy, another diabetes-related eye condition. DME happens when damaged blood vessels in the eye start to leak into the part of the retina called the macula, causing blurry vision and even vision loss.
The good news is that regular screenings and early detection can help reduce your risk. For people already living with DME, there are multiple treatment options to help manage DME and even improve vision.
What causes diabetic macular edema?
High blood sugar levels over time can damage blood vessels in the retina, located at the back of the eye. These damaged vessels may cause fluid to leak into the retina, resulting in swelling. In DME, the swelling affects a central part of the retina, the macula, which is responsible for the sharp, central vision we use for reading, driving, and recognizing faces.
DME is a complication of diabetic retinopathy that can occur in people with any type of diabetes. Other risk factors include duration of diabetes, your A1C, and whether you have other health conditions, such as high blood pressure or high cholesterol and lipids.
Symptoms of DME may include:
- Blurry vision
- Vision loss
- Double vision
- Eye floaters (specks or dots in your vision)
- Loss of color
- Poor dark-light adaptation
It’s important to note that DME often may have no symptoms, which is why it’s crucial for people with diabetes to get regular eye exams.
How to prevent diabetic macular edema
The main approach to preventing DME is by treating the underlying cause, which is high blood sugar. A single high blood sugar event will not cause DME. Instead, DME is a result of prolonged high blood sugar levels over time.
The first steps your healthcare provider will recommend are ways to help improve blood sugar management. This may involve aiming to increase time in range, lower your A1C, change your diet, exercise regularly, and adjust medications. It may also be helpful to monitor other factors that might influence diabetes management, such as blood pressure, cholesterol, and lipids. It is also very important to get annual dilated eye exams to catch DME early – an early diagnosis can lead to better treatment outcomes.
Screening for diabetic retinopathy
In the early stages of DME, it’s common not to have symptoms, which is why regular eye exams are crucial. Early detection and treatment of DME can help prevent vision loss. Regular dilated eye exams may allow your optometrist or ophthalmologist to identify DME early and get treatment started right away.
There are a few different exams that look for DME:
- Slit-lamp biomicroscopy: This is a non-invasive test that requires pupil dilation. This routine exam involves resting your chin on a support while your doctor adjusts the light and looks through a microscope to see different structures in your eye.
- Optical coherence tomography (OCT): OCT is the gold standard for testing for DME and works best with pupil dilation. OCT is a non-invasive imaging test where you rest your chin on a support and look at images while the instrument scans your eye. It measures retinal thickness, which can show how much fluid is present if DME is present.
- Fluorescein angiography: This test requires pupil dilation and what’s called a fluorescein injection. This imaging technique looks at fluorescein (a dye) that is injected into a vein (typically in your arm) to look at the blood vessels in your eye. Your doctor will use a special camera to detect the dye in your eye and be able to identify where to focus treatment. This is not a typical screening method, but it can be helpful once DME has already been identified.
Treatment options for diabetic macular edema
In addition to general glucose management strategies, there are several treatments and procedures currently used to heal the retina and repair vision for people with DME.
Anti-VEGF injections
People with DME produce too much of a protein called VEGF, which is responsible for blood vessels growing too quickly and eventually leaking fluid into the macula. Anti-VEGF injections block the VEGF protein to stop this from happening.
Currently, anti-VEGF injections are the first line of therapy for DME. These injections may be administered once a month for the first three to six months, with fewer injections needed as treatment goes on. A specialist will use numbing eye drops before the procedure, so you won’t feel the injection. Once the blood vessels stop leaking, your vision should begin to improve.
Common anti-VEGF medications:
- Ranibizumab (Lucentis)
- Aflibercept (Eylea)
- Bevacizumab (Avastin)
- Faricimab-svoa (Vabysmo)
- Brolucizumab (Beovu)
- Pegaptanib sodium (Macugen)
Steroids
In roughly 40% of people with chronic DME, anti-VEGF therapy is not enough to improve symptoms. Corticosteroids (steroids) are medications that target inflammation and swelling in the retina and can be administered as either an injection or a slow-release implant in the eye. The implant eliminates the need for multiple injections and naturally dissolves at the end, so a separate procedure to remove it is not needed.
Steroid treatment can speed up cataract progression, so it should not be the first line of therapy. Common steroids used to treat DME include:
- Dexamethasone (Ozurdex): A dissolvable implant
- Fluocinolone (Iluvien, Retisert): A non-dissolvable implant
- Triamcinolone (Xipere, Triesence, Trivaris): Injected directly into the eye
NSAID eye drops
Nonsteroidal anti-inflammatory drugs (NSAIDs) function similarly to steroids by targeting inflammation and swelling, but without some of the side effects of steroids, such as eye pain and dry eye.
As a milder solution, NSAIDs could be helpful for people who are unable to tolerate steroids. Common NSAID eye drops include bromfenac (Bromsite) and ketorolac (Acular).
Laser therapy
Also known as laser photocoagulation or focal-grid macular laser surgery, this advanced procedure is helpful for people who have not responded well to anti-VEGF medications or other treatments. This procedure uses a laser to seal the retina’s damaged and leaky blood vessels, which can bring down the swelling. This 15-minute laser surgery might be done once or multiple times, depending on how the retina responds.
Treatment options on the horizon
Research on future DME treatments is focused on repairing or replacing the damaged retina. With gene therapy, genetic material is introduced into the eye so the body can produce proteins like anti-VEGF that protect the retina from the effects of DME. There’s also a new oral compound currently being studied in clinical trials that, if successful, would be the first-in-class oral treatment for DME.
Multiple ongoing studies are testing a promising new injectable treatment called Restoret (MK-3000, formerly EYE103), which is designed to repair blood vessels in the eye rather than only treat symptoms, to see how effective it is compared to current anti-VEGF medications like Lucentis.
Another treatment being studied is retinal transplantation, which replaces damaged retinas. This could be done by either directly transplanting a healthy retina or injecting stem cells that transform into healthy retinal cells.
The bottom line
DME is a complication of diabetic retinopathy that happens when high blood sugar damages vessels in the eye over time. DME can result in blurry vision and eventually vision loss. It can affect people with any type of diabetes and may not have symptoms at first, which is why annual eye exams are key for early therapeutic intervention.
There are several treatment options for DME, with anti-VEGF injections being the first line of therapy. If anti-VEGF treatment does not work, steroids and laser therapy are other options. Managing blood sugar levels and getting regular eye screenings are the best ways to keep up with your eye health and prevent DME or catch it early.
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