Velocimetrie par effet doppler optique des globules rouges a differentes profondeurs dans les vaisseaux retiniens en variant la longueur de coherence temporelle de la source: Etude de faisabilite

Purpose: To report on a novel approach to measure the velocity of red blood cells (RBCs) at different retinal vessel depths. Method: The technique is an extension of conventional laser Doppler velocimetry using light sources of various coherence lengths (CL). Light scattered by the moving RBCs interferes with that reflected from the anterior vessel wall only if the optical path difference is shorter than CL. Therefore, using low coherence light sources, localized measurements of RBCs velocity can be performed. Results: Measurements of RBCs velocity at different depths in a main retinal vein (diameter: 152 μm) of a volunteer has been performed using 4 different light sources with CLs of 14 μm, 21 μm, 32 μm and > m. Measured values are in good agreement with theoretically predicted values. Conclusion: This new approach permits to measure RBCs velocity at different depths of retinal vessels in the human retina.