The transfer coefficients of fluorescein in the anterior chamber by flow, kfa, and by diffusion, kdpa, can be calculated for an individual human eye, through an analysis of fluorescein concentrations in the anterior chamber, pupillary aqueous, and serum ultrafiltrates following intravenous injection. Using this technique, aqueous humor dynamics was studied in eight patients with glaucomato-cyclitic crisis. In seven patients, the coefficients determined during the attacks averaged 1.23 +/- 0.08 (S.E.M.) X 10(-2) min.-1 for kfa and 3.51 +/- 0.81 X 10(-3) min.-1 for kdpa in the involved eye, and 0.91 +/- 0.12 X 10(-2) min.-1 for kfa and 1.36 +/- 0.39 X 10(-3) min.-1 for kdpa in the fellow eye. The differences in the coefficients between the two eyes were statistically significant (P less than 0.05). In six patients, the coefficients were measured during the remission, giving average values of 0.81 +/- 0.08 X 10(-2) min.-1 for kfa and 1.36 +/- 0.16 X 10(-3) min.-1 for kdpa in the involved eye, and 0.78 +/- 0.07 X 10(-2) min.-1 for kfa and 1.20 +/- 0.10 X 10(-3) min.-1 for kdpa in the fellow eye. The differences in the coeficients between the two eyes were not significant. In five patients, the determinations were repeated during the attack and remission, and the differences in the coefficients between both phases were statistically significant (P less than 0.05) in the involved eye.