Age-related changes in the pediatric human orbit on CT.

PURPOSE: The purpose of this study was to characterize the relationships among orbital dimensions, globe diameter, and subject age.
METHODS: A cross-sectional, retrospective analysis of 124 CT scans of subjects with no appreciable orbital or globe disease was performed by 1 observer (G.K.E.). Seventeen length measurements and 5 angle measurements of various aspects of the orbit were obtained. Subjects of similar age were grouped and analysis was performed to define the changes in these parameters in association with age.
RESULTS: One hundred twenty-four CT scans of 124 subjects without identifiable globe or orbital disease were included in this study. Twenty-one subjects ≥ 17 years of age were considered mature adults and grouped together, while the remaining 106 subjects were grouped according to age. Intraobserver variability between orbital measurements was excellent, r > 0.95 (p ≤ 0.01) for most measurements. There was no difference between right and left orbital measurements, as each was highly correlated to its contralateral counterpart. Globe diameter and all length measurements except globe protrusion increased most rapidly over the first 12 to 24 months and reached 86% to 96% of their respective adult means by age 8 years. Globe diameter and linear orbital measurements were highly correlated. Globe protrusion and measurements of orbital angles exhibited a different pattern.
CONCLUSIONS: The pattern of human orbital growth is strongly correlated with the pattern of ipsilateral globe growth. This change is most rapid during the first 12 to 24 months of life and maintains a significant pace until reaching 86% to 96% of adult values for most parameters at age 8 years. After this age, the rate slows considerably until maturity. With this attempt to define normal age-related orbital change, the authors report a pattern of growth which may be clinically applicable in the management of pediatric anophthalmos.