Demonstration of a diffusional pathway between the subretinal space and the juxtapapillary connective tissue. An in...

A defect in the blood-retina barrier in the optic nerve head region has been demonstrated. In order to show the exact localization of this defect, an in vitro experiment has been performed on rabbit eyes, using horseradish peroxidase as a tracer. From a subretinal depot the tracer diffused between the innermost retinal pigment epithelial cell and the cells of Kuhnt intermediary tissue into the border tissue of Elschnig and the juxtapapillary choroid. The defect in the permeability barrier is thus located to the junction between the retinal pigment epithelium and the Kuhnt intermediary tissue. The role of the junctional complexes in the Kuhnt intermediary tissue in relation to the blood-retina barrier is discussed.