What is diabetic macular edema?

Swelling of the macula, a spot near the center of your retina that lets you see objects in sharp detail, can cause vision problems or blindness.

Diabetic macular edema refers to swelling (edema) in the central part of the retina (macula) that happens in some people with diabetes. This swelling is a serious eye complication.

The retina is a thin layer of tissue that lines the back inner wall of your eye. It has millions of light-sensitive cells that allow it to function like a camera — receiving, organizing and sending information to your brain so that you can see. The macula is a spot near the center of your retina that lets you see objects in sharp detail. Swelling in this central spot can cause vision problems or blindness.

Diabetic retinopathy

Your retina is protected by a barrier of cells that are joined tightly together. In people with diabetes, chronic high blood sugar levels can trigger a cascade of complex processes that disrupt this barrier. Too much sugar in your blood can also damage the tiny blood vessels that nourish the retina or block them completely. This can harm the retina and is known as diabetic retinopathy.

Diabetic macular edema can occur with either of the two major types of diabetic retinopathy. But it's more likely to occur in the more severe stages of retinopathy:

  • Nonproliferative diabetic retinopathy (NPDR). In this type of diabetic retinopathy, the weakened blood vessels in the retina form tiny bulges, called microaneurysms. Blood vessels may also become blocked, which deprives areas of the retina of oxygen and nourishment from the blood. Nonproliferative retinopathy can be mild, moderate or severe, depending on how damaged the blood vessels are, but it doesn't always require treatment.
  • Proliferative diabetic retinopathy (PDR). In this type of diabetic retinopathy, areas of the retina that are deprived of blood and nourishment signal the body to grow (proliferate) new blood vessels. However, the new blood vessels are often fragile and may bleed or detach the retina from the inside wall of the eye. These abnormal blood vessels can also leak blood or fluid into the center of the eye. Proliferative retinopathy can cause blindness if left untreated.

Many people with type 1 or type 2 diabetes will develop some form of diabetic retinopathy. Although most retinopathy is mild and doesn't destroy vision, it's important not to take any chances. If you have diabetes, make sure to schedule regular eye exams to screen for diabetic retinopathy and diabetic macular edema.

March 02, 2018 See more In-depth