Effect of consecutively applied fluorescein eye drops on corneal and aqueous concentrations of fluorescein.

The main objective of this study was to determine the intraocular concentration of fluorescein after applying five eye drops with only 1-min intervals in human eyes. The concentration of fluorescein in corea and aqueous was studied with fluorophotometry in 11 healthy volunteers. Five 10-microliter drops of 2% fluorescein solution were administered with 1-min intervals, and the intraocular concentrations that were achieved were compared with those obtained with just one eye drop. Five consecutive fluorescein drops caused a 2.6- to 3.1-fold increase in fluorescein concentrations of the anterior chamber 1-8 h after application compared with a single eye drop (p < 0.05). Corresponding values for the cornea were 2.1-2.8. As a conclusion, administration of five eye drops applied consecutively significantly increases intraocular drug concentration during 8 h in humans.