A Novel Three-Dimensional Vector Analysis of Axial Globe Position in Thyroid Eye Disease

Purpose. to define a three-dimensional (3d) vector method to describe the axial globe position in thyroid eye disease (ted). methods. ct data from 59 patients with ted were collected and 3d images were reconstructed. a reference coordinate system was established,and the coordinates of the corneal apex and the eyeball center were calculated to obtain the globe vector ec→. the measurement reliability was evaluated. the parameters of ec→ were analyzed and compared with the results of two-dimensional (2d) ct measurement,hertel exophthalmometry,and strabismus tests. results. the reliability of ec→ measurement was excellent. the difference between ec→ and 2d ct measurement was significant (p=0.003),and ec→ was more consistent with hertel exophthalmometry than with 2d ct measurement (p<0.001). there was no significant difference between ec→ and hirschberg test,and a strong correlation was found between ec→ and synoptophore test. when one eye had a larger deviation angle than its fellow,its corneal apex shifted in the corresponding direction,but the shift of the eyeball center was not significant. the parameters of ec→ were almost perfectly consistent with the geometrical equation. conclusions. the establishment of a 3d globe vector is feasible and reliable,and it could provide more information in the axial globe position. © 2017 jie guo et al.