Retinal Blood Flow Derived From Dye Dilution Curves

Abstract

• A television system was used to record retinal fluorescein dilution curves. In pigs, fluorescein was injected intravenously (IV), into the left ventricle (ILV), and ILV during bilateral carotid occlusion (ILV_CO). Dye dilution curves from points on a retinal artery-vein pair, from two points on a single artery, and from two points on a single vein were recorded by a storage oscilloscope, using two photodetectors positioned over the television image of the vessels. Dye curves were less dispersed following ILV than following IV injections, and were irregular following ILV_CO injection. The dye appearance time was shortest after injection with ILV and progressively longer with ILV_CO and IV. The artery-vein mean transit time was greatest during carotid occlusion. Retinal blood flow in a venous segment was calculated to be 0.149 ± 0.037 ml/min. This value was reproducible following both IV and ILV injections but could not be obtained following ILV_CO due to irregularity of the curves. It was in the same range as that found (0.095 ± 0.011 ml/min), using the radioactively labeled microsphere technique. The system was subsequently tested in humans and was found to give reproducible dye curves. The usefulness of the system as a clinical tool is presently being explored. (Arch Ophthalmol 95:297-301, 1977)