Definition:

Macular edema is a common feature of many diseases of the retina, such as intraocular inflammation (uveitis), central or branch retinal vein occlusion, diabetic retinopathy and following cataract extraction. It is characterized by a retinal thickening in the macular area due to the breakdown of the blood-retinal barrier. Extracellular fluid accumulates in the intraretinal area or collects in the subretinal space. In more severe cases, it occurs as cystoid edema with the typical petaloid appearance, and is the leading cause of visual loss. New treatments for macular edema have emerged over the past decade, the most recent and efficacious of which have involved blockage of vascular endothelial growth factor (VEGF) by frequent intravitreal injection of pharmacologic agents.