Diabetic macular edema (DME) is swelling in the macula (the center of the retina) that is caused by diabetes type 1 or 2.  Chronically high levels of blood glucose can cause detrimental changes in the blood vessels of the retina.  These blood vessels can become leaky over time — fluid can leak out of the vessels and into the retina.  The retina then becomes swollen and central vision may become blurry.  All patients with diabetes should have regular dilated eye examinations looking for DME.  If DME is detected, it may require treatment with laser, or injections of medication into the eye (anti-VEGF or steroid), or around the eye (steroid).  With successful treatment, the swelling may be reduced and visual improvement may occur.