Diffusion coefficient through the blood-aqueous barrier using a standard protocol.

AIMS/BACKGROUND: Comparison of the diffusion coefficient through the blood-aqueous barrier of healthy volunteers measured in different cities with identical fluorophotometers using a standardised protocol. METHODS: Healthy volunteers aged between 20 and 70 years were studied in seven European cities. The fluorescein concentration in the anterior segment of each eye was measured with a commercial scanning fluorophotometer 30 and 40 minutes after intravenous fluorescein. The decay of non-protein bound fluorescein concentration in blood plasma was determined with the use of three blood samples taken at 7, 15, and 55 minutes after injection. The diffusion coefficient through the blood-aqueous barrier was calculated from the ratio between the fluorescein concentration in the anterior chamber and the time integral of non-protein bound fluorescein concentration in plasma using specially developed software. RESULTS: The mean values of the diffusion coefficient (SD) (X10(-4) min-1) were 4.76 (1.51) (n = 20, Brussels), 5.48 (2.33) (n = 17, Coimbra), 3.47 (2.09) (n = 12, Cologne), 6.09 (2.77) (n = 21, Frankfurt), 3.85 (1.59) (n = 11, Ghent), 4.99 (1.69) (n = 23, Leiden), and 4.87 (1.05) (n = 20, Madrid). The values between centres were similar (Kruskal-Wallis test p > 0.05) except for Cologne and Frankfurt (p = 0.013). No differences were found when repeating measurements (four centres, interval time 1-8 months, Wilcoxon paired test p > 0.39). CONCLUSION: The diffusion coefficients had similar values and standard deviations. The concerted action demonstrated the usefulness of a standardised protocol.

Phacoemulsification and IOL implantation in eyes with cornea guttata.

During the period from April 1990 until August 1991 in 217 eyes with cornea guttata (and clear cornea) a cataract extraction with implantation of a posterior chamber lens was performed. Of these, 189 eyes (146 patients) underwent a phacoemulsification procedure. According to semiquantitative endothelial cell microscopy in the central area of the cornea, the eyes were classified into three groups: Group I (n = 126): solitary defects (< 5) in the central endothelial layer. Group II (n = 49): several defects (> 5) in the central endothelial layer. Group III (n = 14): considerable defects (> 50% of the central endothelial layer). Postoperative follow-up (2 to 7 months) was without any complication in Group I: i.e. all corneas were immediately clear and remained clear until today. In Group II we observed a mild transient corneal edema in 4 of 49 eyes on the first postoperative day which disappeared spontaneously after one to three days. In Group III a mild transient corneal edema was seen in 11 of 14 eyes on the first postoperative day which disappeared in 1 to 4 weeks. All 14 corneas are still clear today.