[The optics of retinal blood vessels and their significance for scanning laser Doppler flowmetry].
Recently, the scanning laser Doppler flowmetry (SLDF) has been developed as a standard method for the quantification of retinal blood flow. However, the measured quantities flow, volume, and velocity depend on the angle between the direction of the blood flow and of the light. The underlying theory assumes isotropic illumination of the vessel. This assumption, however, is not valid for light back-scattered from retinal vessels. This paper investigates the contribution of different pathways of the light to the SLDF signal by a Monte Carlo simulation. It is shown that the light measured on a vessel having a thickness of 50 microns is predominantly back-scattered from the blood inside the vessel, whereas the measurement on vessels 20 microns in diameter or less also includes light transmitted through the vessel.
Hammer
M
M
Klinikum der Friedrich-Schiller-Universität Jena, Klinik für Augenheilkunde, Bachstrasse 18, 07740 Jena. Martin.Hammer@med.uni-jena.de
Schweitzer
D
D
Königsdörffer
E
E
Strobel
J
J
D001783:Blood Flow Velocity / Q000502:physiology; D001810:Blood Volume / Q000502:physiology; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008833:Microcirculation / Q000502:physiology; D009010:Monte Carlo Method; D055095:Optics and Photonics; D012171:Retinal Vessels / Q000502:physiology*; D012542:Scattering, Radiation