Blood–ocular barrier

Blood–ocular barrier is a term used to describe the barrier that exists between the blood and the ocular tissues. This barrier is essential in maintaining the proper functioning of the eye by controlling the substances that can pass from the blood into the ocular tissues.

Function

The primary function of the blood–ocular barrier is to protect the eye from potentially harmful substances in the blood. It does this by selectively allowing certain substances to pass through while blocking others. This selective permeability is crucial for maintaining the proper balance of nutrients and electrolytes in the ocular tissues.

Structure

The blood–ocular barrier is made up of two main components: the blood-aqueous barrier and the blood-retinal barrier. The blood-aqueous barrier is located in the ciliary body and iris of the eye, while the blood-retinal barrier is located in the retina.

Blood-Aqueous Barrier

The blood-aqueous barrier is formed by the endothelial cells of the blood vessels in the ciliary body and iris, as well as the non-pigmented epithelial cells of the ciliary body. These cells are joined together by tight junctions, which prevent most substances from passing through.

Blood-Retinal Barrier

The blood-retinal barrier is formed by the endothelial cells of the blood vessels in the retina, as well as the retinal pigment epithelium. Like the blood-aqueous barrier, these cells are joined together by tight junctions.

Clinical Significance

Disruption of the blood–ocular barrier can lead to a number of ocular diseases, including uveitis, macular edema, and diabetic retinopathy. In these conditions, the barrier becomes permeable to substances that it would normally block, leading to inflammation and damage to the ocular tissues.

See Also

• Blood-brain barrier
• Blood-testis barrier