Demonstration of ocular blood/tissue and blood/fluid barriers

In addition to previous fluorescence-microscopic investigations on ocular barriers, quantitative fluorescence-photometric measurements on the eye tissues of albinotic rats were performed. The eyes were enucleated 5-30 min after intravenous injection, and tissue samples were compared with analogous eye tissues of untreated animals. The results were (I) different increases of measured data in the region of endothelium and stroma of the cornea, of vessels and stroma of the ciliary body and iris, of choroid and choriocapillaris, as well as of pigment epithelium and retina vessels; (II) no increase of the photometer values was observed in the epithelium of the cornea and in all other external and internal layers of the retina. It is to be assumed that in contrast to the tissues and vessels mentioned in (I), no measurable amounts of fluorescein have penetrated into the retina layers mentioned in (II). Although the fluorescence-photometric method may not be absolutely conclusive, it could be established that measurements are more exact than the qualitative method performed by fluorescence-microscopic observation.