Electroretinogram changes after fluorescein injection: a new method to evaluate blood-retinal barrier dysfunction.

When a retina with an impaired blood-retinal barrier (BRB) is illuminated with blue light (480 mm) after intravenous fluorescein (F) injection, photoreceptors are presumed to be stimulated not only by the original blue light but also by a green one (520 mm) that is emitted by the leaked F. In the present study, the value of the electroretinogram (ERG) was examined before, and up to 10 min after, F injection in normal subjects and diabetics without overt retinopathy. In normal subjects, the amplitude of the b-wave was affected by F injection and stayed within +5.0% /+- 11.8% at 2 min and -2.1% /+- 16.4% at 10 min (mean +/- S.D.) of those recorded before administration of the dye. In the diabetic patient without overt retinopathy, the ERG was enhanced by F injection and the values were significantly larger than those of normal subjects at 0.25 (p < 0.001). 1 (p < 0.05), 2 (p < 0.005), 3 (p < 0.005), and 10 (p < 0.01) min after injection. It may be concluded from these results that a comparison of the ERGs before and after F injection can be useful in demonstration of impairment or destruction of the inner and outer BRB.