Quantification of effective orbital volume and its association with axial length of the eye. A 3D-MRI study

Abstract

Objective: To measure the effective orbital volume (EOV) from magnetic resonance images, and investigate its relationship with axial length (AL) in those parameters. Methods: Cross-sectional, 3D-MRI study. 54 eyes of 54 patients (25 males) were included in this work. Patient weight, height and head circumference were also measured. Orbital and eyeball volumes were calculated after image segmentation. The difference between those values volume was assessed, estimating the EOV for each eye. Results: Mean eyeball volume was 7.83 ± 2.27 mm 3 , mean orbital volume 26.81 ± 0.59 mm 3 and EOV 21.64 ± 0.19 mm 3 . The orbital volume was significantly higher in the male group (Wilcoxon signed-rank tests Z=-1.51, p<0.001; Z=-3.57, p<0.001 respectively). EOV was significantly correlated with AL in both males (r=-0.71, p<0.001) and females (r=-0.73, p<0.001), whereas it was also significantly associated with patient height (r=0.261, p=0.03). Associations between EOV and other age, axial and anthropometric characteristics were not statistically significant. Conclusions: Findings of this study could be of valuable importance in various clinical situations in which quantification of orbital volume is needed, such as orbital decompression in Graves' orbitopathy, volume restoration in orbital fractures or other orbital reconstructive surgery. In surgical interventions, clinical relationships should be carefully taken under consideration to avoid iatrogenic injury.

Orbital Volume and Axial Length Development in Individuals Ages 12 to 60 Years With Congenital Microphthalmia: A Retrospective Cohort Study

“…Bontzos et al demonstrated that normal orbital volume was significantly correlated with axis length 25 . Our work found a positive linear correlation between orbital volume and axis length in the affected and unaffected eyes.…”

“…Bontzos et al demonstrated that normal orbital volume was significantly correlated with axis length. 25 Our work found a positive linear correlation between orbital volume and axis length in the affected and unaffected eyes. The results of our predictive modeling indicated that every 1 mm change in axis length caused a 0.38 cm 3 change in orbital volume in the affected group and a 0.73 cm 3 change in the unaffected group.…”

Long term follow‐up of axial length and orbital dimensions in congenital microphthalmia and anophthalmia

“…Our findings confirm a relation between smaller AL and more asymmetrical orbits, with mild cases not affecting orbital symmetry and voluminous intra‐orbital cysts causing a strikingly larger orbit. The relationship between AL and orbital volume has repeatedly been established (Bontzos et al., 2019; Yang et al., 2012; Ye et al., 2022). We observed more orbital asymmetry in cases with eyes smaller than 10.5 mm.…”

CT parameters in pure orbital wall fractures and their relevance in the choice of treatment and patient outcome: a systematic review

“…These ambiguous results might be explained by the broad variety of methodologies used to measure and process orbital volumes. Moreover, in these small study populations, the inter-individual and intra-individual differences in orbital volume, as well as the differences in orbital volume between the sexes (20-32 ml, 2.5-4.1%, and around 8%, respectively) may also be of importance 39,[51][52][53] . This is especially the case, since the mean range of the orbital volume difference between the injured and uninjured orbits is 1.4-5.7 ml, which is around 5-21% (using a mean orbital volume of 27 ml) 27,28,38,39 .…”