Fig. 1

Layers of the normal retina. Low magnification: 1, inner limiting membrane bordering the vitreal body (V) constituted by a thin basal lamina, Bruch Membrane (BM). The opposite face of this BM shows delicate projections of Müller glial cells sealed each other by scattered tight junctions just above the BM; 2, layer mainly constituted by axons of ganglion neurons which form the optic nerve at the papilla;3, ganglion multipolar neurons layer; 4, inner plexiform layer; 5, inner nuclear layer; 6,outer plexiform layer; 7, outer nuclear layer; 8, outer limiting layer where abundant Zonulae adhaerentes (ZA), belt- shaped, are located between the photoreceptor neurons and the tinny terminals of Müller’s glial cells; 9, inner and outer segments of rods and cones layer; 10, pigment epithelial cells with varieties of junctional complexes between them . Richness in tight junctions plus normal integrity of Bruch membrane constitute the major morphological bases for the blood-retinal barrier; 11, Bruch membrane, a thin basal membrane (indicated with a black triangle, ▼) that adjoins to the extracellular spaces of chorio-capillaris (CC) or Choroidea, the medium layer of the eyeball showing abundant small blood vessels (bv) mainly fenestrated capillaries with a thin continuous BMs and venules containing scarce red blood cells (rb) distributed within scarce loose connective tissue (ct)