Studies on the technique of vitreous fluorophotometry.

We examined the sources of artifacts of vitreous fluorophotometry (VF), a technique used to assess the permeability of the blood-retinal barrier. By performing in vitro measurements in a model eye and in vivo readings in humans, we investigated the influence of various concentrations of fluorescein in the anterior chamber and in the retina on the measurements performed in the vitreous. Upper limits for the artifactual effects are set under clinical conditions, and a way to account for them is proposed. Special attention is given to depth resolution, which was investigated as a function of the region being scanned, the beam width, and the probe size. Further, preliminary results indicate that a procedure to account for light attenuation by the lens is feasible. It appears that reliable quantitative results can be obtained by VF, provided that the artifacts are acknowledged, minimized, and corrected.