Insights into the Physiopathology of Inflammatory Macular Edema

Macular edema is one of the most common causes of permanent vision loss in patients with uveitis. The current understanding of water balance and metabolism within the retina has given us better insight into the mechanisms underlying macular edema arising from both acute and chronic inflammation. Uveitic macular edema (UME) occurs when the equilibrium between water influx and efflux is lost, and more importantly when compensatory mechanisms are overwhelmed. While in the acute setting, control of inflammation can reestablish homeostasis, chronic inflammation can lead to alternate pathways to establish a water balance. To understand UME, one must understand the regulation and consequences of inflammation at the tissular level. A fine interplay exists between inflammation and the retina replete with compensatory mechanisms, bystander effects, and structural sequelae once inflammation subsides. This understanding may allow us to develop new therapeutic strategies for the treatment of inflammatory macular edema.