PERMEABILITY OF THE BLOOD-RETINAL BARRIER IN HEALTHY HUMANS - EUROPEAN CONCERTED ACTION ON OCULAR FLUOROMETRY

Background: The aim of the study was to compare the inward permeabilit y of the blood-retinal barrier in healthy subjects from six European c ities. a Methods: Seventy-two healthy subjects (age 20-70 years) were selected. At 30 min and 60 min after fluorescein injection, fluorescei n mass in vitreous was calculated from the concentrations measured alo ng the optical axis of the eye. Non-protein-bound fluorescein (NPBF) c oncentrations were measured in plasma prepared from blood samples take n 7, 15 and 55 min after injection. Blood-retinal barrier permeability (P-BRB) was calculated from the vitreous fluorescein mass and the tim e integral of NPBF and was corrected for the autofluorescence of ocula r tissue and for lenticular light transmittance. Results: Mean P-BRB v alues+/-SD (nm.s(-1)) were 2.07+/-0.54 (Coimbra), 2.01+/-0.43 (Frankfu rt), 2.24+/-0.50 (Ghent), 2.37+/-0.56 (Herlev), 1.89+/-0.44 (Leiden) a nd 1.74+/-0.38 (Porto). Differences between centers were not significa nt (P>0.35), Measurements were reproducible and independent of the tim e after fluorescein injection (P>0.50). A P-BRB higher than 3.16 nm.s( -1) or a value which had increased by 32% was considered abnormal (P<0 .05). Conclusion: P-BRB values were similar in all centers. The result s demonstrate that this is a highly sensitive and reliable method for measuring the permeability of the blood-retinal barrier.