Measurement of blood-retinal barrier function in central retinal vein occlusion

P. S. Chahal, T. J. Fallon and E. M. Kohner

Vitreous fluorophotometry was used to measure blood-retinal barrier permeability to fluorescein in eight patients (mean age, 42.9 years; range, 30 to 55 years) with central retinal vein occlusion (CRVO). Permeability coefficient was derived by fitting a mathematical model to the posterior vitreous fluorescence scan and plasma-free fluorescein concentration curve at 60 minutes after intravenous fluorescein sodium (14 mg X kg-1). A permeability index (PI) was estimated by dividing the area under the vitreous fluorescence scan by the area under the plasma-free fluorescein curve. The permeability coefficient and PI were comparable and highly correlated. Initial mean permeability coefficient was 28.78 X 10(-7) cm X s-1 (range, 14.42 X 10(-7) to 41.10 X 10(-7) and 1.89 X 10(-7) cm X s-2 (range, 0.96 X 10(-7) to 2.76 X 10(-7) in eight affected and seven unaffected eyes, respectively. The permeability coefficient and PI in unaffected eyes did not differ significantly from 18 eyes of ten normal subjects. After three to 12 months, permeability coefficient and PI in affected eyes approached the values in the contralateral eyes of four patients with mild and one patient with moderate CRVO but remained elevated in the remaining patients. The permeability coefficient and PI correlated well with changes in severity of retinal appearances on color photographs and fluorescein angiograms. Vitreous fluorophotometry quantitated changes in blood-retinal barrier permeability in CRVO.