FIGURE 3.

The retina is a tissue composed of several layers of cells. Retinal pigment epithelium is a layer of cells, which is in close contact with the outer layer of photoreceptor cells. Photoreceptor cells are divided into cones and rods. The cell bodies of rods and cones form the outer nuclear layer. The photoreceptor forms synapses with the bipolar and horizontal cells that make up the outer plexiform layer. The cell bodies of bipolar cells, horizontal cells and amacrine cells form the inner nuclear layer. The synapses between retinal ganglion cells (RGCs), bipolar cells, and amacrine cells form the inner plexiform layer. The axons of RGC form the optic nerve, which connects the retina to the brain. The retinal neurovascular unit is composed of ganglion cells, glial cells (astrocytes and Müller cells), immune cells (microglia), and vascular cells (endothelial and pericytes), reflecting the complex functional coupling and interdependence between different retinal cells.