Diabetes, eye surgeries, and aging — what do these all have in common? They’re three of the 10 causes of macular edema, which is fluid buildup and swelling in the central part of your retina. Left untreated, macular edema can lead to vision problems and eventually, vision loss.

In this article, we’ll cover the 10 main causes of macular edema to be aware of if you’re living with diabetes. With this knowledge, you can be better prepared to talk with your doctor if you begin experiencing new vision symptoms.

What Is Macular Edema?

The retina is the light-sensitive tissue in your eyes that sends what you see to your brain. It’s found at the very back of your eye, connected to the optic nerve. Damage to this important tissue can lead to vision impairment or loss.

Macular edema occurs when leaky blood vessels let blood and fluid build up in the macula of your eye. This is the central part of the retina needed to see colors and fine details. Pressure from the fluid buildup causes edema (swelling) and thickening in your retina.

Symptoms of macular edema include:

• Blurry vision that continues getting worse over time
• Wavy vision, especially when looking straight ahead
• Colors looking faded or dull
• Objects appearing to be different sizes when looked at with one eye vs. the other

So, what causes macular edema? Here, we’ll break down the 10 causes, including underlying health conditions, surgery, and injuries.

1. High Blood Sugar Levels From Diabetes

People with both type 1 and type 2 diabetes are at increased risk for developing eye problems. This is because high blood sugar levels can damage the delicate blood vessels that bring oxygen and nutrients to the retina. These vessels then leak fluid into the eye, causing a condition known as diabetic retinopathy. When there’s fluid buildup in the macula specifically, it’s known as diabetic macular edema (DME).

Elevated blood glucose (sugar) levels also tell the cells in your eyes to make vascular endothelial growth factor (VEGF) proteins. These proteins are responsible for creating new blood vessels. However, in DME, new vessels are also leaky and don’t work properly. Without proper treatment, DME can lead to vision loss.

Because high blood sugar is responsible for causing leaky blood vessels, the first step in treating DME is getting your levels under control. Other treatment options include:

• Anti-VEGF injections that block VEGF proteins
• Corticosteroids or nonsteroidal anti-inflammatory drugs (NSAIDs), which reduce inflammation
• Laser treatments
• Eye surgery

2. Age-Related Changes in Your Eyes

As we age, the tissues in our eyes begin to change. You may develop age-related macular degeneration (AMD) or changes to your macula. There are two types of AMD — wet and dry.

Wet AMD is the more serious form that causes new, abnormal blood vessels to form beneath the retina. As with DME, VEGF proteins create these vessels that leak fluid and blood into the macula. This leads to swelling and scar tissue formation that interferes with your vision. People with wet AMD lose their vision faster than those with dry AMD.

Risk factors that increase your chances of developing AMD include:

• Being 50 or older
• Smoking
• Eating a diet with too much saturated fat
• Having untreated hypertension (high blood pressure)

Anti-VEGF injections can treat wet AMD and related macular edema by stopping new, leaky blood vessel formation. Photodynamic therapy — a combination of laser therapy and medications — can also prevent further vision loss.

3. Blockages in Your Eyes’ Veins

Your veins are responsible for carrying blood from your body back toward your heart. Blockages in these blood vessels can have damaging consequences. Central retinal vein occlusion (CRVO) occurs when the vein carrying blood from your retina becomes clogged or blocked by a blood clot. Pressure builds up in the eye behind the blockage, causing blood and fluid to leak into the retina. Macular edema can also develop from this leakage, leading to central vision loss. Central vision is your field of view as you look straight ahead and is integral to seeing shapes, colors, and details.

If CRVO is left untreated, the nerve cells in your eyes can’t get enough oxygen and nutrients and they die.

4. Genetic Eye Diseases

“Retinitis pigmentosa” refers to a group of rare genetic eye diseases in which the cells in the retina break down slowly over time. Researchers estimate that between 10 percent and 50 percent of people with retinitis pigmentosa are affected by cystoid macular edema. Doctors and researchers aren’t quite sure why this is the case, but they have some theories. One theory is, the breakdown of the blood-retinal barrier — which lets fluid leak out into the eyes — causes fluid-filled cysts to form on the macula, leading to swelling and vision loss.

5. Macular Pucker

Macular pucker is a rare eye condition that causes bulges, creases, or wrinkles on your macula. Aging is the most common risk factor for the condition, as the vitreous or gel-like substance in your eyes shrinks with age. If it gets stuck on the macula, scar tissue forms and makes the macula pucker. When your macula isn’t lying flat against your eye, you’ll have wavy, blurry, or dull vision. This also leaves space underneath the macula for fluid to collect, leading to macular edema.

6. Inflammation of the Eye

Uveitis is an inflammatory eye condition that causes inflammation of the uvea — the middle layer of the eye (including the iris and the layer just under the retina). In intermediate uveitis, your immune system attacks your eyes and damages your retina’s blood vessels. If it’s left untreated, uveitis can eventually lead to macular edema and vision loss. Symptoms of uveitis to look out for include red, painful eyes, floaters (dark spots in your vision), and sensitivity to light.

7. Eye Tumors

Both malignant (cancerous) and benign (noncancerous) eye tumors can cause macular edema. Most benign tumors don’t cause vision loss — however, if they develop in the macula, they may cause central vision loss. Choroidal tumors are cancerous tumors that can cause cystoid macular edema. This is likely due to inflammation and leaky blood vessels around the tumor.

8. Eye Surgeries

Although not as common, some people develop macular edema after eye surgery to treat glaucoma, cataracts, or problems with their retina. Your eye’s sensitive tissues can become inflamed after a procedure, leading to swelling in the macula. For example, you have a higher risk for developing cystoid macular edema after cataract surgery. It tends to go away within three to four months of surgery.

9. Certain Medications

When prescribing your medications, your doctor will weigh the benefits of the drug and its potential side effects. Some medications for cancer, autoimmune diseases like multiple sclerosis, and diabetes — including rosiglitazone (Avandia) and pioglitazone (Actos) — have been found to cause cystoid macular edema. Fortunately, most cases resolve on their own after a person stops taking the medication. If your symptoms continue, your doctor can prescribe anti-inflammatory drugs to help.

10. Eye Injuries

Injury or trauma to the eye can also cause macular edema. Common causes of eye injuries include falling or playing sports. Commotio retinae, or Berlin’s edema, is caused by retinal damage from trauma. It can affect your macula or the outer edges of your retina. Be sure to talk to your eye specialist if you were recently hit in the eye and are experiencing vision changes.

Talk to Your Doctor About Macular Edema

If you’re experiencing any new changes in your vision or signs of macular edema, talk with your doctor. They can refer you to an ophthalmologist (a physician who specializes in eye diseases) to diagnose and treat you. Your treatment plan will be based on what’s causing your macular edema and how severe your symptoms are.

The overall goal of treating this condition is to control swelling, inflammation, and leaky blood vessels. Examples of treatments include:

• Injections into the eye
• Prescription eye drops
• Surgical or laser treatments

If you’re living with diabetes and other chronic health conditions, it’s important to visit your eye specialist annually. They can check your eye health and look for any signs of macular edema or other damage. This is the best way to preserve your vision for years to come.

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