A barrier comprised of retinal cells joined tightly to limit the movement of ions, cells, and other substances between the retinal capillaries and the retinal tissue
The blood-retinal barrier is able to restrain the flow of certain substances from the capillaries to the tissue of the retina through the characteristics of cells comprising the barrier:
- an inner layer made up of retinal vascular endothelial cells that are nonfenestrated and joined tightly by zonulae occludens
- an outer layer of retinal pigment epithelial cells joined tightly by zonulae occludens
Diabetic retinopathy can disrupt this barrier and therefore lead to diabetic macular oedema, which can impair the vision of diabetic patients.