Figure 3.

Retinal cellular architecture, retinal pigment epithelial (RPE) cells and retinal capillary endothelial (RCE) cells represent the outer and inner retinal barriers, respectively. RPE and RCE compose the main organization of the transport limiting layers. The outer layer of the retinal pigment epithelium displays tight barriers due to the presence of tight junctions (zonula occludens). Inner retinal capillary endothelial cells possess tight junctions and are non-fenestrated as opposed to choroidal capillary endothelial cells.