Diabetic Macular Edema

Definition

Macular edema is swelling in part of the retina (the light-sensitive layer of tissue at the back of your eye). People with macular edema may have blurry vision, but treatment can help reduce the swelling and prevent vision loss.

Symptoms

Blurry vision and vision that gets worse over time are the main symptoms of macular edema. You may also notice that:

• Objects look wavy, especially when you look straight ahead
• Objects look like they’re different sizes if you look out of one eye and then the other
• Colors look dull or faded

If you only have macular edema in one eye, it may take longer for you to notice changes to your vision.

For some people, macular edema only causes mild blurry vision. For others, it causes more severe central vision loss, which can make it hard to do everyday activities like reading and driving.

Causes

Macular edema happens when blood vessels leak into a part of the retina called the macula. This makes the macula swell, causing blurry vision.

There are many different conditions that can cause macular edema. The most common one is diabetic retinopathy — an eye condition that causes vision loss in people with diabetes. When diabetic retinopathy causes macular edema, it’s called diabetic macular edema (DME).

If you have diabetic retinopathy, managing your diabetes can help prevent or delay vision loss. It’s also important to get a dilated eye exam at least once a year.

Other causes of macular edema include:

• Age-related macular degeneration (AMD). In a certain type of AMD called wet (or neovascular) AMD, abnormal blood vessels in the macula leak fluid into or under the retina, which can cause swelling in the macula. Learn more about AMD.
• Retinitis pigmentosa (RP). RP is a genetic disease. Some people with RP can also have swelling in the macula. Learn more about RP.
• Uveitis. Uveitis is inflammation inside the eye that happens when the immune system attacks eye tissue. It can cause swelling in any part of the eye, including the macula. Learn more about uveitis.
• Blocked veins in the retina (retinal vein occlusion). When veins in the retina are blocked, blood can’t drain the way it should and it leaks into the macula — which can cause swelling. Learn more about central retinal vein occlusion.
• Eye surgery. Some people develop macular edema after having surgery to treat another eye condition, like cataracts. This swelling is often mild, but it’s still important to get treatment right away to help prevent future vision loss.
• Certain medicines. Some medicines, like medicines to treat glaucoma, can cause macular edema as a side effect.

Diagnosis

Eye doctors can check for macular edema as part of a dilated eye exam. The exam is simple and painless. Your doctor will give you some eye drops to dilate (widen) your pupil and take a look at the retina.

If your doctor thinks you have macular edema, they may do more tests to find out for sure. For example:

• Fluorescein angiogram. This test lets the doctor see pictures of the blood vessels in your retina. Your doctor will inject a special dye into your arm. The dye travels through your bloodstream from your arm to your eye. Then the doctor will use a camera to take photos as the dye flows through the blood vessels in your retina.
• Optical coherence tomography (OCT). This test lets the doctor see the back of your eye by taking pictures of the retina and other parts of the eye with a special machine. This can help your doctor see how much swelling there is.
• Amsler grid. This test tells the doctor if you’ve lost any of your central vision. Your doctor will ask you to look at a picture of a grid. If part of the grid looks wavy or dark, you may have central vision loss.

Treatment

If you have macular edema, finding the cause and treating that condition can help with your macular edema symptoms. For example, if you have diabetic macular edema (DME), taking steps to manage your diabetes can help prevent vision loss. Your doctor may also recommend one of the following treatment options:

Injections. Medicines called anti-VEGF drugs can slow down or reverse macular edema. Medicines called steroids can also help with swelling in the retina. Your doctor will usually inject these medicines into — or very close to — your eye.

Eye drops. Your doctor may recommend a type of eye drops called nonsteroidal anti-inflammatories (NSAIDs). These can help prevent or treat macular edema caused by surgery. Your doctor may recommend you use these eye drops by themselves or along with steroid eye drops.

Laser treatment. Certain types of laser treatment can be used to treat macular edema when it’s caused by another condition, like diabetes or retinal vein occlusion. Your doctor might recommend laser treatment if injections haven’t worked to treat your macular edema.

Eye surgery. Your doctor may recommend a type of surgery called a vitrectomy if other treatments haven’t worked. During a vitrectomy, your doctor will make very small openings in your eye wall and remove most of the vitreous (gel-like fluid that fills your eye) from your eye with a suction tool. Your doctor may also recommend a surgery to implant a device that makes it easier to get regular injections.