Abstract A method is described for taking motion pictures (10 to 16 frames per second) of the passage of fluorescein through the retinal vessels. Fluorescein dye injected into an antecubital vein has been photographed during its passage through the retinal vasculature with a specially adapted motion picture camera and binocular ophthalmoscope. The entire sequence of retinal flow can be continuously visualized without resort to multiple injections and the grouping arrangements necessary with "still" techniques. Studies in 60 patients have demonstrated the sequence of retinal arteriolar, capillary, and venous blood flow with a clear portrayal of laminar flow both in arterioles and veins. This technique provides a safe, convenient, and reliable means for observing the hemodynamic changes in the retinal circulation due to a variety of physiologic stimuli and for studying the alterations in retinal blood vessels in a number of disease states affecting the optic nerve and retina.