The Pathophysiology of Subretinal Hemorrhage

Abstract

Subretinal hemorrhage (SRH), the accumulation of blood between the neurosensory retina and the retinal pigment epithelium (RPE), may arise from the choroidal or retinal circulation or both. Different pathological entities affecting these circulatory systems as well as trauma may be the cause of SRH. Independently from the underlying trigger, SRH damages tissue through a variety of mechanisms: The presence of iron, hemosiderin, and fibrin in the blood has toxic effects on the overlying photoreceptors; clot retraction can sheer and damage the photoreceptors; and, finally, physical separation of the photoreceptors from the RPE may impair nutrient exchange and can result in atrophy of both the neurosensory part and the RPE. Finally, the development of a disciform scar associated with an uninterrupted exudative process will lead to further anatomical and functional deterioration. As the mechanisms of damage are time-dependent, the goal of the following outline is to provide a review on the underlying mechanisms with an emphasis on how changes are shaped through time.