A wind turbine includes a number of blades and an optical measurement system comprising a light source, such as a laser, an optical transmitter part, an optical receiver part, and a signal processor. The light source is optically coupled to the optical transmitter part, which includes an emission point for emitting light in a probing direction. The optical receiver part comprises a receiving point and a detector. The optical receiver part is adapted for receiving a reflected part of light from a probing region along the probing direction and directing the reflected part of light to the detector to generate a signal used to determine a first velocity component of the inflow. The emission point is located in a first blade at a first radial distance from a center axis, and the receiving point is located in the first blade at a second radial distance from the center axis.