While the treatment is performed, you will be asked to look at a light under the laser. You are required to look steadily at the light throughout the operation, since this keeps the eye centred under the laser. However, if you temporarily look away or lose the ability to look at the fixation light, do not be concerned. The LadarVision 4000 is equipped with a special eye tracker that tracks the eye at 4000 times a second throughout the procedure.