choriocapillarisa

Choriocapillaris, sometimes seen in older texts as choriocapillarisa, is a single-layer network of capillaries forming the vascular inner layer of the choroid in the eye. It lies just external to Bruch’s membrane and the retinal pigment epithelium, and internal to the larger-caliber vessels of the choroid.

The choriocapillaris consists of fenestrated endothelial cells supported by a basal lamina, which allows rapid exchange of nutrients and waste between the blood and the outer retina. It supplies the outer retina, especially the photoreceptors and the retinal pigment epithelium, with oxygen and nutrients essential for visual function. The network exhibits high perfusion and is capable of adapting to metabolic demand.

Developmentally, the choriocapillaris arises from the choroidal vasculature derived from the short posterior ciliary arteries, forming a dense, lobular arrangement beneath Bruch’s membrane in humans. It is part of the broader choroid, which also includes the intermediate Sattler’s layer and the outer Haller’s layer of larger vessels.

Clinical significance: dysfunction or dropout of the choriocapillaris is associated with diseases affecting the outer retina, notably age-related macular degeneration and various inflammatory or ischemic conditions. Damage to the choriocapillaris can contribute to outer retinal degeneration, while choroidal neovascular processes that originate in the choroid may impact the outer retina. Imaging modalities such as OCT angiography and indocyanine green angiography are used to assess choriocapillaris perfusion in research and clinical practice.