Blood–ocular barrier
Physical barrier between the local blood vessels and most parts of the eye itself / From Wikipedia, the free encyclopedia
The blood–ocular barrier is a barrier created by endothelium of capillaries of the retina and iris, ciliary epithelium and retinal pigment epithelium.[1] It is a physical barrier between the local blood vessels and most parts of the eye itself, and stops many substances including drugs from traveling across it.[2] Inflammation can break down this barrier allowing drugs and large molecules to penetrate into the eye.[3] As the inflammation subsides, this barrier usually returns.
It consists of the following components:
- Blood–aqueous barrier: the ciliary epithelium and capillaries of the iris.[2] Blood-aqueous barrier is formed by nonpigmented ciliary epithelial cells of the ciliary body and endothelial cells of blood vessels in the iris.
- Blood–retinal barrier: non-fenestrated capillaries of the retinal circulation and tight-junctions between retinal epithelial cells preventing passage of large molecules from choriocapillaries into the retina. Formed by endothelium of retinal vessels and epithelium of retinal pigment. [4][5]