[Intravitreal injection. Drugs to treat subretinal hemorrhage]

Since 1996 acute subretinal hemorrhages have been treated by intravitreal injections. Large proteins injected into the vitreous cavity can cross the retina as well as the underlying retinal pigment epithelium. After intravitreal injection of tissue plasminogen activator (TPA), plasminogen, which is part of a subretinal clot, is converted to plasmin in the presence of fibrin. Plasmin is a relatively unspecific protease that liquefies a formed fibrin clot. Simultaneous intravitreal injection causes an inferior displacement of the liquefied hemorrhage. Beside mechanical effects on subretinal clots plasmin inhibits choroidal neovascularization by hydrolysis of the extracellular matrix as well as growth factors. After successful displacement of a subretinal hemorrhage an additional anti-VEGF (vascular endothelial growth factor) therapy is required.