Normative globe position values on orbital computed tomography in Australians.

Objective: To determine normal globe position values, interzygomatic distance (IZD), and globe axial length and width on computed tomography in an Australian cohort.

Design: Retrospective cohort study.

Participants: Patients who underwent computed tomography of the orbits. Patients with bilateral disease, previous orbital surgery, or poor scan quality were excluded.

Methods: An axial slice through the midglobe was used to conduct the globe position measurements. Anterior globe position was defined as the perpendicular distance from the anterior globe margin to the interzygomatic line and posterior globe position as the perpendicular distance from the posterior globe margin to the interzygomatic line.

Results: The normal measurements (mean ± SD) were IZD, 97.4 ± 4.1 mm; anterior globe position, 18.8 ± 2.8 mm; posterior globe position, 6.2 ± 2.9 mm; axial globe length, 24.9 ± 1.1 mm; and axial globe width, 25.9 ± 1.2 mm. A significant positive correlation was seen between the IZD and the anterior globe position (r = 0.15, p = 0.03), axial globe length (r = 0.33, p < 0.01), and axial globe width (r = 0.30, p < 0.01).

Conclusion: This normative globe position data may be used to diagnose radiologic exophthalmos or enophthalmos.