Retinal vein occlusions (RVO) are common retinal diseases. They are caused by an obstruction of retinal veins. RVO often result in visual deterioration and, in rare cases, can lead to blindness, but also be asymptomatic. The prognosis is various and depends on the extent, the localization of the occlusion and the retinal perfusion, especially in the macular area. The etiology often is a thrombosis caused by vascular sclerosis, rarely a vasculitis. Because often an underlying disease is present the medical clarification is necessary. The ophthalmological treatment of the macular edema includes intravitreal injection of VEGF inhibitors and steroids. Laser photocoagulation is being proposed as second line treatment. Neovascular complications like preretinal neovascularizations with and without vitreous hemorrhage are treated with laser or vitrectomy. Iris neovascularization can also occur and is treated with laser photocoagulation or cyclophotocoagulation.