Diabetic macular edema.

Diabetic macular edema (DME) is one of the most common causes of visual loss in patients with diabetes mellitus. Many patients continue to lose vision despite laser photocoagulation and medical therapies. The two major categories of medications currently used to treat DME are corticosteroids and anti-VEGF agents. The vitreous has been implicated as a cause of macular edema in people with diabetes via several mechanical and physiologic mechanisms, all of which are postulated to lead to increased vascular permeability. Vitrectomy can release the mechanical traction on the macula and increase oxygenation with subsequent reduction in DME. Early vitrectomy even in nontractional DME results in significant macular thinning and may lead to rapid improvement in vision with long-term stabilization. Unfortunately, a randomized trial pitting vitrectomy against the methods currently employed has not yet been performed.