Estimation of permeability in blood-retinal barrier

Permeability of the blood-retinal barrier (BRB) can be determined by vitreous fluorophotometry and computer analysis. In this study, we characterize our eye model and apply it to normal human subjects. In this investigation of BRB permeability, we employed four parameters for the eye model: the inward permeability (Pin) and outward permeability (Pout) of the BRB; the diffusion coefficient in the posterior vitreous gel (D-p); and the plasma fluorescein concentration. The values of Pin, D-p, and plasma fluorescein concentration significantly affected the fluorescein concentration in the posterior vitreous 60 minutes after intravenous fluorescein injection. The value of Pout had little influence on the fluorescein kinetics in the posterior vitreous 60 minutes after injection. The results of experiments on humans indicate that the estimated values obtained by simulation fit satisfactorily the measured values. It is suggested that our computer simulation method in conjunction with vitreous fluorophotometry can effectively estimate permeability of BRB in normal and pathological eyes.