In vivo and in vitro tracer studies, e. g., fundus fluorescein angiography, fluorescein and lanthanum tracer procedures were carried out on mild and severe blunt ocular trauma in rabbits to investigate pathological changes of the blood retinal barrier. Noo difusion of the tracers was found in the retinal after mild blunt trauma. However, severe disorganization of the retinal pigment epithelial cells and breakdown of the outer blood retinal barrier with permeation of tracers in the interphotoreceptor space were evident after severe blunt trauma. These results suggest that contusional retinal edema is mainly due to disruption of cells in the outer retinal layer barrier may, in part, play a role in pathogenesis of the retinal edema. （Chin J Ocul Fundus Dis,1992,8:130-132）