Cyclotorsion Outcomes with Bausch & Lomb Dynamic Rotational Eyetracker

Purpose: To investigate the amount of cyclotorsion during LASIK by means of Bausch & Lomb's dynamic iris eyetracker. Method: Eighty-eight consecutive patients (159 eyes) who had undergone LASIK surgery between September 2006 and January 2007 were involved in this study. The amount of cyclotorsion during the laser procedure was recorded as the maximum, average and minimum positions by using the active rotational eyetracker in Bausch and Lomb Hi-Tech laser system. Results: The amount of cyclotorsion was defined as the difference between the maximum and minimum positions. It was non-directional. The total amount of cyclotorsion during the procedure ranged from 0.0 deg to 13.4 deg (mean: 2.351 deg±1.604). 10 out of 159 eyes (6.29%) revealed cyclcotorsion of more than 5 deg and 1 eye (0.63%) revealed cyclotorsion of more than 10 deg. The extreme ends of cyclotorsion were –10 deg and +14.1 deg. All eye rotations occurred within this range. Conclusion: Cyclotorsion occurs before and during laser treatment. An active rotational eyetracker will be imperative in compensating for such cyclotorsional movements during the laser procedure and will enable surgeons to obtain better treatment precision especially in patients with high astigmatism, wavefront-guided or topography-guided treatment.