Macular Edema – What Is It, What Causes it and How Does it Affect Vision?

Macular Edema – What Is It, What Causes it and How Does it Affect Vision?

Posted under Low Vision Info

Macular edema (ME) refers to the swelling or fluid accumulation under a specific area of the retina, known as the macula.  A healthy macula is needed for sharp vision and to see details in clear focus. This tiny portion of the retina is rich in photoreceptor cells called cones which are responsible for not only clarity but for our central or straight ahead vision.  When fragile blood vessels grow in an abnormal way they leak or ooze fluid and blood.  If this leaking occurs under or near the macula, you get macular edema.  The accumulated fluid has nowhere to go and no way of being absorbed.


What Causes Macular Edema

What causes this swelling or fluid build up to occur?  ME in and of itself is not an eye disease but rather it develops as a result of other health or eye problems. There are several different diseases or eye conditions  that can lead to ME.  Some of the common causes are:

1. Diabetes

Diabetes can affect and change the integrity of blood vessel walls of the retina causing them to weaken in a way that allows fluid to leak out wreaking havoc with one’s vision.

2. Age related macular degeneration

The wet form of age related macular degeneration is given its name because fragile blood vessels grow up from the the choroid layer, the layer of blood vessels that feed the retina. Fluid leaks out of them causing the macula to swell.

3. Eye Surgery

ME can also develop after eye surgery for cataracts, glaucoma or a retinal detachment.

4. Retinal Vein Occlusion

The veins of the retina can become blocked. When a vein is blocked the blood is unable to drain and the excess fluid leaks into the retina sometimes reaching the macula.

5. Inflammatory Eye Diseases

Uveitis, sarcoidosis, and toxoplasmosis are linked to inflammation and can lead to swelling in the macula.

6. Genetic Disorders

ME can be a complication of retinitis pigmentosa, a genetic disorder that affects peripheral and side vision.


How Does Macular Edema Affect Vision

There is no pain involved with ME. The severity of vision changes can be mild to moderate to severe.  Usually peripheral vision is not affected.  The five most common symptoms are:

1. Blurred Vision

The most noticeable blurred vision occurs right in the center of one’s vision.

2. Wavy Vision

Lines that should appear straight are slanted, distorted or wavy.

3. Faded Color Vision

Colors appear dim, less vibrant or less vivid.

4. Loss of Contrast Sensitivity

Distinguishing between similar colors, like navy blue and black, becomes difficult.

5. Blank Spots

Blank, gray or black spots appear in one’s field of vision.  These “blank spots” are called scotomas.


Learning to maximize your useable vision becomes more important as the symptoms of macular edema may be temporary or they may become permanent depending on what the cause is and how one responds to treatment.

For more information visit: Macular Edema


Leslie Degner, RN, BSN