Permeability of blood-ocular barriers of neonatal and adult cat to sodium fluorescein.

The permeability of the ocular blood vessels to sodium fluorescein (NaFl) was evaluated in neonatal and adult cats by fluorescence microscopy. The iris, ciliary body, and choroidal vessels were markedly permeable, whereas the mature and immature retinal vessels were impermeable. Since there is no apparent barrier to NaFl at the level of the iris vessels, the role of those vessels in aqueous formation is possibly significant. The fact that the immature retinal vessels are impermeable suggests that abnormal permeability to NaFl in retinal neovascularization is a consequence of pathology rather than immaturity.