Globe Positioning in the Orbit among Filipinos Scanned at the Philippine General Hospital from November 2009 to February 2010

Nonette A. Cupino,1 Erwin John T. Carpio1 and Paulo Maria N. Pagkatipunan2

1Department of Radiology, College of Medicine and
Philippine General Hospital, University of the Philippines Manila
2Department of Ophthalmology, College of Medicine and
Philippine General Hospital, University of the Philippines Manila

Objective. To determine normal Filipino values of globe positioning in the orbit using Computed Tomography.

Methods. 58 individuals were divided into age groups below 20 and 20 and above. CT images with constant settings were obtained. The distance between the lateral orbital rims (A), the shortest distance between line A and the corneal center (B), medial and lateral orbital rims (C), and the distance between line C and the corneal apex crossing the center of the lens (D) were measured, and the B/A and D/C ratios calculated. The mean, median, and range in millimeters were grouped in terms of age, sex, and laterality.

Results. Between the age groups, there was a significant difference in the average values of A, B, and C, but not the B/A and D/C ratios. Gender comparison for group 2 showed statistical difference in the average values of B and C, but not the A, D, B/A and D/C ratios. All the parameters in both groups showed no significant difference when the right and left eyes were compared.

Conclusion. Age group comparison showed statistically significant difference in the average values of A, B, and C which may be attributable to growth changes. Gender comparison in group 2 showed significant difference in B and C. Males had a greater degree of protrusion than females. The right and left eye showed no significant difference in any of the measured parameters. Throughout the study, both B/A and D/C ratios showed no significant difference among gender and age suggesting that such ratios may be used as an index for setting normal globe positioning in the orbit.

Key Words: age, computed tomography, globe, orbit, position