To quantify the cyclotorsion that occurs between upright sitting and supine positions in Taiwanese subjects. Methods: The Visx WaveScan Wavefront device was used to obtain images of 105 eyes (54 patients) when the patients were seated. An infrared camera was then mounted on the Visx Star S4 Excimer Laser System to obtain further images in the supine position. We compared the eye positions at the time of the wavefront measurement with those in the supine position to estimate the amount of cyclotorsion. Results: For all 105 eyes, the mean±SD cyclotorsional deviation was 2.6±2.0 degrees (right eye 2.4±3.8 degrees counterclockwise, left eye 2.7±2.9 degrees clockwise). Binocular excyclotorsion was the predominant trend, affecting 48 of 54 patients. Conclusions: The difference in cyclotorsional eye movement, measured with IR-Visx CV technology, was significant in the transition from seated to supine positions. The cyclotorsional deviation can be used to adjust the laser ablation algorithm to compensate for this rotational displacement.