Many patients worry about this, and the concern is sometimes substantial. Almost everyone moves a tiny bit during the procedure. Under the laser microscope, a person’s face and eyes can move (slightly) in concert with normal breathing. This is why we perform every surgery with “assisted stabilization” to assure ideal rendering and centration of the laser treatment, and/or we use lasers with pupil-tracking systems. Also, we can pause the laser treatment whenever we want, and resume when it is safe, stable, and proper to do so.