The Measurement Of Normal Orbital Bony Cavity And Soft Tissue Volume Based On Three-Dimensional Reconstruction By CT Scans

OBJECTIVE:To provide reference values for orbit volume and orbital soft tissue volumes in southern Chinese adults. And analyze the differences between orbital tissue volume with respect to age and sex and to assess any correlation between height, weight, orbital parameter, and orbital volume.PATIENTS AND METHODS:Computed tomographic scans of 103 orbits from 52 men and 51 women, aged 18-81 years, not affected by orbital disease were evaluated. Orbital bony cavity volume (OV), fat volume (FV), extraocular muscle volume (MV) and optic nerve volume(NV) were calculated by a previously validated method using the software program Mimics. Eyeball volume(BV), transverse globe protrusion(EX), posterior pole of eyeball to orbital apex(PA) were measured too.RESULTS:OV, FV, MV and NV in men and women of southern Chinese respectively are 22.21±2.17cm3,8.89±1.79 cm3,1,94±0.34cm3,0.41±0.08cm3 and 20.18±1.54 cm3,8.09±1.74 cm3,1.57±0.28 cm3,0.36±0.07 cm3. OV, FV, MV and NV were all significantly larger in men than in women (p<0.05), and all volumes in southern Chinese are smaller than in Caucasians. In both sexes, OV did not change with age, FV increased with increasing age, whereas the other volumes decreased. FV and MV showed positive correlations in EX and PA, but negative in BV/OV.CONCLUSIONS:These results provide basic information about the effects of age, sex, height and weight on orbital volumes and orbital parameter in healthy southern Chinese adults. And reference orbital volumes (5 and 95 percentiles) are presented.