Abstract: An apparatus is provided for the measurement of the velocity of blood flowing within a blood vessel of an eye wherein the apparatus includes a light source for producing a source beam of light and an optical element for applying the source beam of light to the blood vessel to permit the blood flowing within the blood vessel to scatter a portion of the source beam of light and produce bidirectional scattered beams. A detector system for detecting the bidirectional scattered beams provides signals representative of the scattered beams. The light source and the detector system are disposed in a confocal relationship. An output representative of the velocity of the blood flow velocity is produced in accordance with the signals. The light source and the detector system include respective pinholes wherein the respective pinholes are disposed in the confocal relationship. The blood vessel is conjugate with the respective pinholes of the light source and the detector system.

Abstract: An interferometric apparatus for monitoring changes of the refractive index of An interferometri1capillary tubes comprising a source of coherent light, which is arranged with respect to a capillary tube which is part of a capillary liquid chromatographic system or a capillary electrophoretic system, such that the coherent light beam strikes the capillary tube about perpendicular to its longitudinal extension. In the forward direction of the coherent light beam, behind the capillary tube, the apparatus comprises a photoelectric detector for monitoring a resulting interference fringe pattern and the shifts thereof, which is connected to an evaluation electronics.