EFFECT OF FLICKER AN MACULAR BLOOD-FLOW ASSESSED BY THE BLUE FIELD SIMULATION TECHNIQUE

Purpose. To determine the effect of diffuse luminance flicker on the m otion of leukocytes in the retinal macular capillaries of normal subje cts. Methods. Using the blue field simulation technique, subjects were asked to match the motion of simulated leukocytes displayed on a vide o monitor to that of their own entoptically seen white blood cells (WB Cs). The changes in velocity and density of the WBCs were recorded aft er stimulation with diffuse luminance flicker of various durations (0 to 16 seconds), either immediately or at various delays (2, 4, 8 secon ds) after cessation of the stimulus. Results. White blood cell, veloci ty increased as flicker duration increased from 0 to 16 seconds. After cessation of flicker, leukocyte motion decreased to baseline within 1 5 seconds. Conclusions. The authors' findings suggest a coupling betwe en retinal neural activity and blood flow in the macular region of the retina. The rapidity of both the flicker-induced increase in WBC moti on and the disappearance of the effect after flicker cessation resembl es the time course of blood flow changes previously observed in the mi crocirculation of the cat optic nerve.