CORNEAL ENDOTHELIAL PERMEABILITY AND AQUEOUS-HUMOR FLOW USING A STANDARD PROTOCOL

Background: The study was carried out to compare corneal endothelial p ermeability and aqueous flow values of healthy volunteers measured in different countries with identical fluorophotometers using a standardi zed protocol. Method: Healthy volunteers aged between 20 and 70 years were studied in five European cities. Fluorescence scans of the anteri or segment of both eyes were made using a commercial fluorophotometer. Beginning 4 h after instillation of four drops of fluorescein 10%, 12 scans of the anterior segment of each eye were performed in 2 h. The values of corneal endothelial permeability and aqueous flow were calcu lated with standardized software from the decay of the fluorescein con centration in the cornea and anterior chamber. Results: The mean perme ability values (x10(-4) cm . min(-1)) +/-SD were 3.7+/-1.6 (n=19; Coim bra, Portugal), 4.3+/-1.1 (n=19; Frankfurt, Germany), 3.9+/-0.9 (n=19; Leiden, The Netherlands) and 5.4+/-1.2 (n=10; Milan, Italy). The valu es were not significantly different (ANOVA, P>0.3), except those in Mi lan. The mean flow values (mu l . min(-1)) +/-SD were 2.3+/-0.9 (n=17; Coimbra), 1.9+/-0.7 (n=10; Cologne, Germany), 2.6+/-1.2 (n=19; Frankf urt), 2.0+/-0.6 (n=19; Leiden) and 1.7+/-0.8 (n=10; Milan). The values were not significantly different (Kruskal-Wallis test, P>0.1). Conclu sions: Permeability and flow values in the different cities had simila r values and standard deviations. The Concerted Action demonstrated th e usefulness of a standardized protocol.