Digital Videographic Measurement of Cyclotorsional Angle in Normal Human Eye

ABSTRACT

The eyeball movement is classified into horizontal, vertical movement and cyclotorsion. The cyclotorsion has been known to be induced by two oblique and vertical rectus muscles. But there have been few precise methods for the measurement of cyclotorsion. So, we tried to find the precise method for the measurement of cyclotorsion with digital videographic method. Sixteen normal volunteers were included in this study, who had no eyeball movement disorders. For the measurement of cyclotorsion that followed by head tilt, the volunteers haed was tilted to fifteen, thirty, forty-five and sixty degree to the left and the partially compensated counter torsion was recorded with video camera. The movement was analyzed with digitally using IBM clone computer. The linear regression equation, between the head tilt and cyclotorsion was Y=2.019 X + 22.2280 (Y=head tilt, X=cyclotorsion) and coefficient of variation(%) was 0.88%. Therefore, our videographic method for the measurement of cyclotorsion was relatively precise and may be applied in the measurement of ocular torsion.