1. Etiology: The vitreous itself is not vascular and does not bleed. Vitreous hemorrhage is mostly caused by internal ocular vascular disorders and injuries, but can also be caused by systemic disorders, usually from the retina and uvea broken blood vessels or neovascularization. The following causes are common: 1, retinal vascular disease: diabetic retinopathy, retinal vein obstruction, retinal vasculitis, etc., bleeding from the lesioned vessels into the vitreous; 2, eye trauma or surgery; 3, other fundus diseases. 2, clinical manifestations: 1, a small amount of blood accumulation, there are mosquitoes, fundus examination can be seen in the vitreous small cloudy points or floating objects, vision is not affected. 2, a large amount of blood accumulation, the vitreous body is highly cloudy, vision is sharply reduced, or even only the sense of light, fundus examination without red light or only faint red light reflection. Slit lamp examination shows a large number of red cells or bright red blood clots in the vitreous. 3, there are manifestations of the primary injury that caused the accumulation of blood in the vitreous. 3.Treatment principles: 1.Little bleeding does not need special treatment, can wait for its own absorption. 2.Suspected presence of retinal fissure, make the patient rest in bed, wait for the blood to sink in time to give laser seal or freeze seal. 3.Large amount of bleeding is difficult to absorb, not combined with retinal detachment and fibrovascular membrane can wait for 3 months, such as vitreous blood still does not absorb vitrectomy, combined with If the retinal detachment or retinal detachment with pulling, vitrectomy should be performed in time.