Blood-retinal barrier

The following is a detailed encyclopedia article on the topic of the Blood-retinal barrier, formatted in MediaWiki source code:

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Blood-retinal barrier

The blood-retinal barrier (BRB) is a physiological barrier that regulates the movement of cells, molecules, and ions between the blood and the retina. It is essential for maintaining the homeostasis of the retinal environment, which is crucial for proper visual function. The BRB is analogous to the blood-brain barrier and consists of two main components: the inner blood-retinal barrier and the outer blood-retinal barrier.

Structure

Inner Blood-Retinal Barrier

The inner blood-retinal barrier is formed by the tight junctions between the endothelial cells of the retinal capillaries. These tight junctions restrict the passage of large molecules and cells, allowing only selective transport of nutrients and waste products. The endothelial cells are supported by pericytes and astrocytes, which contribute to the barrier's integrity and function.

Outer Blood-Retinal Barrier

The outer blood-retinal barrier is formed by the retinal pigment epithelium (RPE), a layer of pigmented cells that separates the neural retina from the choroid. The RPE cells are connected by tight junctions, which prevent the free movement of substances from the choroidal blood supply into the retina. The RPE also plays a role in the transport of ions, nutrients, and metabolic waste products between the retina and the choroid.

Function

The primary function of the blood-retinal barrier is to protect the neural retina from potentially harmful substances in the blood while allowing the selective transport of essential nutrients and removal of waste products. This barrier is crucial for maintaining the ionic balance and metabolic environment necessary for photoreceptor function and overall retinal health.

Clinical Significance

Disruption of the blood-retinal barrier can lead to retinal diseases such as diabetic retinopathy, age-related macular degeneration, and retinal vein occlusion. In these conditions, the breakdown of the barrier can result in retinal edema, hemorrhage, and loss of vision. Understanding the mechanisms of BRB disruption is important for developing therapeutic strategies to treat these diseases.

Also see

• Blood-brain barrier
• Retinal pigment epithelium
• Diabetic retinopathy
• Age-related macular degeneration
• Retinal vein occlusion

External

• Age-Related Macular Degeneration

• Amblyopia (Lazy Eye)

• Anophthalmia and Microphthalmia

• Astigmatism

B

• Behçet's Disease* Bietti's Crystalline Dystrophy

• Blepharitis* Blepharospasm

C

• Cataracts

• Coloboma

• Color Blindness

• Corneal Conditions

D

• Diabetic Retinopathy

• Dry Eye

F

• Floaters

G

• Glaucoma

I

• Idiopathic Intracranial Hypertension

L

• Low Vision

M

• Macular Edema

• Macular Hole

• Macular Pucker

P

• Pink Eye

R

• Rare Diseases

• Refractive Errors

• Retinal Detachment

• Retinitis Pigmentosa

• Retinoblastoma

• Retinopathy of Prematurity

S

• Stargardt Disease

U

• Usher Syndrome

• Uveitis

V

• Vitreous Detachment

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This article provides a comprehensive overview of the blood-retinal barrier, its structure, function, and clinical significance, along with related topics for further exploration.