Effect of topical phenylephrine on the permeability of the blood-aqueous barrier in man.

The effects of a single instillation of 5% phenylephrine on aqueous flow and the coefficient of protein entry into the anterior chamber, an index of blood-aqueous barrier permeability, were determined in normal human eyes by measuring fluorescein concentrations with a fluorophotometer and aqueous protein concentrations with a laser flare-cell meter. Both parameters showed a concomitant biphasic change. The coefficient of protein entry showed significant increases of 31 and 66% at 1 and 2 h, and a significant decrease of 18% at 3 h. Aqueous flow showed significant increases of 81 and 125% at 1 and 2 h and a significant decrease of 20% at 4 h. It is suggested that a change in the permeability of the blood-aqueous barrier might be related to changes in aqueous flow after topical phenylephrine.