What is Macular Edema?

Macular edema develops when damaged blood vessels leak fluid into the macula, causing swelling and blurred vision. The macula is the thin layer of tissue at the back of the eye responsible for sharp, straight-ahead vision. Vision loss may be mild to severe, but in many cases, peripheral vision remains. Macular edema is often a complication of diabetic retinopathy, and is the most common form of vision loss for people with diabetes.

What Causes Macular Edema?

With diabetic retinopathy, blood vessels can swell or become blocked. A blockage signals the body to create new blood vessels. The new vessels are often fragile and can leak.

Eye surgery, including cataract surgery, can increase the risk of macular edema due to blood vessels becoming irritated. Macular edema that develops after cataract surgery is called cystoid macular edema (CME).

Other causes include:

  • Age-related macular degeneration
  • Uveitis
  • Retinal vein occlusion
  • Blockage in the small veins of the retina, due to radiation, macular telangiectasis
  • Side effects of certain medications
  • Certain genetic disorders, such as retinoschisis or retinitis pigmentosa

Symptoms of Macular Edema

Symptoms may include blurred or wavy central vision and/or colors that appear “washed out” or changed. Macular edema is often painless and may display few symptoms when it first develops.

Treatment of Macular Edema

Focal laser treatment can be used to reduce swelling of the macula. Tiny laser pulses are applied to areas of leakage. The pulses stabilize vision by sealing off leaking blood vessels. In some cases, vision loss may be improved.

Medication injection therapy is also used. Two drugs —steroids and anti-VEGF agents — have shown promise. Anti-VEGF drugs target a specific chemical in the eye that encourages abnormal blood vessel growth. Injections are given in the doctor’s office. An anesthetic numbs the eye, then a tiny needle is inserted to deliver the medication near the retina.

For people with diabetes, controlling blood sugar and blood pressure is another method of macular edema treatment. It may take several months for macular edema to resolve.