Cyclotorsional eye rotation may be less severe than previously assumed

Adjusting for possible cyclotorsional movements is of great concern to the surgeon performing keratorefractive surgery or refractive cataract surgery. Previous reports have suggested that cyclotorsional eye rotations from sitting to supine may be as high as 10 to 24 degrees. 

This retrospective study utilized the iris registration software of the VISX excimer laser to measure differences in cyclotorsional positions from sitting to supine in 310 eyes. The authors observed that cyclotorsional rotations were generally small, 1.4° ± 2.04° SD. They suggest that larger deviations in prior studies may have been related to noncyclotorsional factors, such as postural misalignments.

The authors found no significant associations between cyclotorsional eye movements and degree of myopia or astigmatism, keratometry values or vector pupil displacement.

This study provides valuable information to surgeons concerned about cyclotorsional movements affecting their LASIK and cataract surgeries. Refractive surgeons must still identify and adjust noncyclotorsional movements, such as postural misalignments.