What is the method of blood ocular barrier breakdown?

The blood retinal barrier is concomitantly broken down with the lowering of intraocular pressure, which affects the zonulae occludentes of the retinal pigmented epithelium (Verhoeff’s membrane) and the retinal capillaries [13,14,15] (Scheme 2).

What is the blood retinal barrier?

The blood-retina barrier (BRB) is composed of both an inner and an outer barrier. The outer BRB refers to the barrier formed at the retinal pigment epithelial (RPE) cell layer and functions, in part, to regulate the movement of solutes and nutrients from the choroid to the sub-retinal space.

Is the eye behind the blood brain barrier?

The blood–ocular barrier is a barrier created by endothelium of capillaries of the retina and iris, ciliary epithelium and retinal pigment epithelium. 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.

What is intra ocular barrier?

(3) BLOOD –OCULAR BARRIERS  These barriers have two parts: blood-aqueous humor barrier and blood- retina barrier.  The anterior blood-ocular barrier is composed of the endothelial cells in the uvea. This barrier limits the access of hydrophilic drugs from plasma into the aqueous humor.

How are drugs delivered to the retinal system?

There are two basic approaches that can be adopted to improve retinal drug delivery: prolonged and/or retina targeted delivery of intravitreal drugs and use of other routes of drug administration, such as periocular, suprachoroidal, sub-retinal, systemic, or topical.

What is the function of the blood retinal barrier?

Barrier function is alsoimpaired by matrix metaloproteinases (MMPs) from Müller cells, as these MMPs lead to proteolytic degradation of the tight-junction protein occludin. The immune response has developed and evolved to protect the organism from invasion and damage by a wide range of pathogens.

When does a drug need to cross the blood-ocular barrier?

In the case of systemic, suprachoroidal and periocular drug administration, the drug must cross the blood-ocular barrier before it can reach the targets in the retina. Therefore, blood-ocular barriers play an important role in defining drug permeation into the eye and from the eye to the blood circulation.

Where does drug elimination take place in the retina?

Drug elimination from the vitreous cavity takes place via blood-ocular barriers and aqueous humor outflow to the systemic blood circulation. In the case of systemic, suprachoroidal and periocular drug administration, the drug must cross the blood-ocular barrier before it can reach the targets in the retina.