Orbital Growth is Associated with Eyeball Size: A Study Using CT-based Three-dimensional Techniques

This study was aimed to investigate the growth patterns and the relationship of the eyeball and the orbit using computed tomography (CT)-based three-dimensional (3D) techniques.

A total of 175 Chinese patients who had undergone craniofacial or orbital CT scans were enrolled. This study only included data from the unaffected eye and orbit. Images were processed using 3D reconstruction to obtain the eyeball and the orbit parameters.

In early postnatal years, the sizes of eyeball and orbit increased significantly with age (p < 0.001) and reached a turning point at a critical age (8.967 and 12.800 years for the eyeball and orbit volume, respectively). The orbital index and orbital depth index, showing the shape of the orbital aperture and walls, decreased significantly with age (p < 0.001). In all ages, the orbit size was correlated with eyeball size (p < 0.001). The eye-orbit index, equivalent to the ratio of eye volume to orbital volume, declined steadily with age (p < 0.001).

The eyeball and orbit developed rapidly in early postnatal years, and then matured at a critical age. The eyeball size significantly contributed to the orbital growth; this contribution may be reduced as the eye-orbit index decreased with age. To the best of our knowledge, this is the first report on the growth and interrelation of the eyeball and the orbit using CT-based 3D techniques.