Plasma binding of fluorescein in normal subjects and in diabetic patients.

The penetration of systemically administered fluorescein sodium into the eye depends on several factors. One important variable is the unbound plasma fluorescein concentration. We measured the in vitro plasma binding of fluorescein in 200 persons using fluorescence polarization. We demonstrated considerable variability in the degree of plasma binding and also found significant differences between normal persons and diabetic and nondiabetic patients.