Macular edema is a swelling or thickening of the eye’s macula, the part of the eye responsible for detailed, central vision.
The macula is a very small area at the center of the retina—a thin layer of light-sensitive tissue that lines the back of the eye. Light rays are focused onto the retina where they are transmitted to the brain and interpreted as the images you see.
Macular edema develops when fluid or protein deposits collect on or under the macula of the eye and causes it to thicken and swell (edema). The macula does not function properly when it is swollen. The swelling may distort a person’s central vision because the macula holds tightly packed cones that provide sharp, clear, central vision to enable a person to see detail, form and color that is directly in the center of the field of view.
Causes of Macular Edema
There are several potential causes of macular edema and different causes may be interrelated.
Macular edema is commonly associated with diabetes. Chronic or uncontrolled type 2 diabetes can affect peripheral blood vessels including those of the retina which may leak fluid, blood and occasionally fats into the retina causing it to swell.
Age-related macular degeneration may also cause macular edema. As individuals age, there may be a natural deterioration in the macula which can lead to the depositing of drusen under the retina, sometimes with the formation of abnormal blood vessels.
Replacement of the lens as treatment for cataracts can cause pseudophakic macular edema. (pseudophakia means replacement lens) also known as Irvine-Gass syndrome. Cataract surgery sometimes irritates the retina (and other parts of the eye) causing the capillaries in the retina to dilate and leak fluid into the retina.
Chronic uveitis and intermediate uveitis can cause macular edema.
Blockage of a vein in the retina can cause engorgement of the other retinal veins causing them to leak fluid under or into the retina. The blockage may be caused by atherosclerosis, high blood pressure and glaucoma, among other things.
A few congenital diseases are known to be associated with macular edema, including retinitis pigmentosa and retinoschisis.
Depending on the cause of the macular edema and the treatment plan recommended by your doctor, the condition may take several months to resolve. To learn more about macular edema, contact Medical Eye Center at 541-779-4711 or medicaleyecenter.com.