The Pathology of Vitreous Hemorrhage

Abstract

• Vitreous hemorrhages were induced in rabbits by the intravitreal injection of 0.2 ml of autogenous whole blood, and the progressive reabsorption of the blood from the vitreous was followed by ophthalmoscopy, gross pathological examination, and histology. On gross examination, the blood clot remained as a discrete mass for four to six weeks, after which it became considerably reduced in size. The presence of blood exerted severe destructive effects on the gel structure of the vitreous, including posterior detachment of the solid vitreous, liquefaction of the gel, the appearance of prominent vitreous bands, and the formation of a pseudocapsule by the detached vitreous around the blood clot. Small blood deposits remained in several eyes for many weeks. The inflammatory response to intravitreal blood as seen by histology was unusual in several respects. The cellular reaction was low grade, and in particular no polymorphonuclear cells were observed, only mononuclear cells. Aggregates of round cells or multinucleate giant cells were found in association with intact unphagocytosed RBCs after many weeks, which may indicate that macrophages within the vitreous were inefficient. No fibrosis occurred in the rabbit vitreous even with long-standing residual vitreous blood deposits. It is suggested that fibrosis is an unusual sequel to vitreous hemorrhage and is associated with ocular diseases in which vitreous hemorrhage may be an incidental occurrence.