People with diabetes have a risk of diabetic macular edema (DME) which affects vision and can lead to blindness. Managing blood glucose and getting regular eye exams are essential to prevent this condition or catch it early.

Doctors can treat DME symptoms, and having a healthy lifestyle can reduce some risk factors.

This article explores what causes DME and what a person can do to prevent it.

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DME is a complication of diabetes that affects the eyes. It affects 1 in 15 people with diabetes, resulting in more than 20 million cases worldwide.

Both type 1 and type 2 diabetes can lead to DME, which may develop gradually.

Elevated levels of sugar in the blood can cause someone with diabetes to develop diabetic retinopathy. This damages the blood vessels in the eyes.

As a result of this damage, fluid can leak from the blood vessels into an area in the center of the retina. The retina is a thin layer of tissue that lines the back of the inside of the eye. The area in the center is called the macula.

The leaked fluid builds up in the macula, causing swelling, also known as edema. When a doctor detects this, they diagnose DME.

In the early stages, this swelling may cause no symptoms.

Experts say that the location of the swelling, or edema, in the retina determines when the symptoms develop.

If the edema begins outside the central area of the retina, a person usually has no symptoms. As it spreads toward the center, a person may experience:

  • blurred or wavy central vision
  • colors that seem washed out or different
  • difficulty reading

Research confirms that without effective treatment, DME can lead to vision loss and blindness.

An ophthalmologist can examine the retina to determine if someone has DME. They sometimes use eye drops to dilate the pupils in order to see a detailed image.

A 2018 review notes that one sign of DME is the retina becoming thick and hardened.

The American Academy of Ophthalmology (AAO) explains that an ophthalmologist can perform a test called optical coherence tomography. It involves a machine scanning the retina to provide a detailed image of its thickness. This allows the doctor to measure any swelling.

They may also perform fluorescein angiography, which involves injecting yellow dye into a vein in the arm. As this dye travels up through the blood vessels in the retina, a camera takes photos and helps the doctor see how much leakage there is.

The American Diabetes Association notes that treating DME involves controlling levels of blood glucose and taking other steps to manage diabetes better.

In addition, an ophthalmologist may recommend the following treatments.

Anti-vascular endothelial growth factor

An ophthalmologist may treat DME with a drug called an anti-vascular endothelial growth factor (VEGF). This growth factor is a protein that the body uses to produce new blood vessels.

The anti-VEGF drug blocks the protein to slow or stop abnormal blood vessels from forming and to avoid damaging vision.

The AAO says that anti-VEGF treatment improves vision in 1 out of 3 people who take it and stabilizes vision in 9 out of 10 people.

There are three main anti-VEGF medicines:

  • bevacizumab (Avastin)
  • ranibizumab (Lucentis)
  • aflibercept (Eylea)

An ophthalmologist injects the anti-VEGF treatment into the eye using a very thin needle after they have numbed the area. A person may need several treatments.

Laser treatment

The AAO notes that while doctors increasingly recommend anti-VEGF treatment first, in some cases, laser treatment is more appropriate. This is because some people do not respond to anti-VEGF treatment or require too many injections for it to be effective.

However, doctors are unable to use laser therapy when DME is centrally located because of the risk that it could impair vision. Laser therapy can lead to scarring and sco­tomata, a blind spot.


An ophthalmologist may decide that steroids are the best approach if anti-VEGF treatment either reduces the swelling in the the macula inadequately or wears off too quickly.

Steroids may also be appropriate when frequent injections are not suitable for the person.

Doctors either inject the steroids into the eye or administer them with an implant. However, this treatment can lead to a long-term risk of developing cataracts and elevated pressure within the eye.

According to a cross-sectional study in 2014 among adults aged 40 and over in the United States, risk factors for DME were:

  • being Black and non-Hispanic
  • having elevated levels of hemoglobin A1C
  • having had diabetes for longer than 10 years

Other research indicates that the prevalence of DME is substantially higher in people with type 1 diabetes, compared with people who have type 2 diabetes: 14% compared with 6%, respectively, based on worldwide pooled data.

According to a 2018 review, higher systolic blood pressure is a risk factor for DME and increased cholesterol levels are associated with the severity and risk of hardness in the retina.

The American Diabetes Association recommends having annual dilated eye exam to catch DME early.

The 2018 review reports that an ophthalmologist may under emphasize certain factors that are linked to retinal changes. It calls for a more multifactorial approach that aims to reduce hemoglobin A1C, elevated blood pressure, and elevated serum lipids. The researchers say that this can produce measurable effects on macular thickness in as little as 6 weeks.

DME is a serious eye complication that can cause vision problems and vision loss without effective treatment.

Managing blood glucose and having regular dilated eye examinations are key for preventing DME.

In addition, some research suggests that monitoring hemoglobin A1C, blood pressure, and cholesterol levels can help a doctor better understand a person’s risk, and that keeping these factors within healthy ranges provides a good foundation for an ophthalmologist to provide further treatment.