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Abstract
If the blood aqueous barrier is destroyed and a plasmoid aqueous formed, marked structural changes occur which permit the leakage of protein from the ciliary capillary to the aqueous humor. This is largely due to disjunction of the endothelial cells and enlargement of intercellular spaces of both epithelial layers of the ciliary process. The electron dense particles used in these experiments were seen to pass from the ciliary capillaries between the endothelial cells, although some passage via cytoplasmic vesicles and pores may have occurred. Diffusion across the connective tissue spaces appears to be unimpeded, but the basement membranes of the capillaries and of the epithelium restrict, but do not prevent, passage of such particles. The pathway through both the pigment and surface epithelium was almost exclusively intercellular. The large spaces were formed by disengagement of the interdigitations of the epithelial cells, and disruption of their desmosomal linkages. The basement membrane covering the surface cells and lining the posterior chamber appeared also to offer some, but by no means great, restriction to the passage of particles of the size used.