The invention relates to a measuring device and to a method for measuring parameters of a body tissue using an elongate probe (1) for insertion into the body tissue, comprising at least one optical waveguide (2) for transmitting light beams that runs along the longitudinal axis of the probe within the probe, an exit region (5) from which light beams emitted from the optical waveguide exit into the body tissue, and at least one receiving region (6) through which light beams reflected and/or scattered in the body tissue enter the probe as input light beams on a photodetector or in an optical waveguide (2; 3). The exit region (5) is provided at the distal end of the probe (1) and is oriented at least partially in the longitudinal direction of the probe (1). At least some of the emitted light beams exit the probe in the longitudinal direction of the probe. The at least one receiving region (6) is located at a distance from the distal end of the probe on a lateral circumferential region of the probe. The input light beams entering a receiving region (6) are subject to a deflection of more than 90° relative to the light beams emitted from the exit region (5).