In various embodiments, a surgical instrument is provided that may comprise an end effector for performing a surgical procedure on tissue, for example. The intraocular device is inserted into an eye, and one or more optical characteristics of the eye, including the intraocular device, are measured. The eye-tracking data is obtained with an eye-tracking system. Alternatively, a dispensing socket of plastic material having an outer thread is fused to the outer edge of the discharge opening and the dispensing valve is secured on the dispensing socket by a union nut. The radar system is characterized in that the supply network operates at least one partial antenna of the transmitting module together with a group of partial antennas of the receiving module or a group of partial antennas of the transmitting module together with at least one partial antenna of the receiving module in a further operating mode. In order to at least partially compensate for incorrect incident flow of the supporting fins, more particularly in partial load operation, the supporting fins have a hub on the inner end thereof, the axial end of said hub having additional openings for blowing out the blow-off air in the diffuser channel.