What is macular edema?
Macular edema is swelling and thickening of the macula (the central portion of the retina). If we think of the eye as a camera and the macula is the film in the camera, then fluid leaking in the macula is like taking a picture with wet, warped film. Images can look blurry, wavy, or warped. Macular edema can occur for several reasons and can produce mild to severe central vision loss. Below are some of the most common reasons people may develop macular edema:
1. Inflammation: The eye can become inflamed after routine eye surgery or because of an underlying inflammatory condition. Just as inflammation causes swelling in any part of the body, it can cause the macula to swell and thicken. This type of macular edema is usually treated with anti-inflammatory eye drops, but severe or prolonged cases may require injections of molecular agents or anti-inflammatory medications such as steroids into or around the eye.
2. Fluid leakage inside the retina: Damaged blood vessels, as in diabetic retinopathy or vascular occlusions, can leak clear fluid from the bloodstream. This fluid is retained in the macula and causes swelling. Depending on the source and amount of leakage, focal laser and/or medication injections may be required to reduce the swelling.
3. Fluid leakage under the retina: Abnormal blood vessels invade the space under the retina in wet macular degeneration. When this happens, fluid can leak out of these blood vessels and cause the retina to swell. Treatments for wet macular degeneration are aimed at stopping the leakage from these abnormal blood vessels and include medication injections and in some cases, “cold” laser (photodynamic therapy) or “hot” laser targeting the leaking vessels.
4. Wrinkling of the macula: Sometimes, mechanical distortion of the macula can occur when a layer of scar tissue forms over the surface of the macula and pulls on the macula. This pulling causes the macula to become wrinkled and thickened. An example of this type of macular edema occurs in a condition called macular pucker. The treatment for this type of macular edema is vitrectomy surgery with peeling of the scar tissue. This releases the macula from the scar tissue and allows the swelling to decrease, with resolution of the distortion and improved vision.