A real-time refractory control system includes a laser refractive surgery instrument for modifying the refraction of the eye, an objective diagnostic apparatus for measuring the refraction and aberrations of the eye, and an aperture-sharing element to inject a refractive surgery beam and a monitoring diagnostic beam. The arrangement also includes a control unit that generates the first and second control signal for the voltage transformer circuit depending on a reference signal in the form of an open-loop control or in the form of a closed-loop control. As such, the boots can be used to cushion the feet while applying traction to the leg during surgery.