The CT scans (Aquilion TSX-101A; Toshiba Medical Systems Corp, Tokyo, Japan) were obtained using continuous 2-mm-thick axial slices by tilting each patient's head parallel to the Frankfurt plane. All images were obtained in a high-resolution osseous window level setting and transferred to 2 different 3-D reconstruction software programs (Vitrea Version 3.4; Vital Images Inc, Minnetonka, Minnesota; and Dextroscope Version 1.0; Bracco AMT Inc, Princeton, NJ). The software was used to configure area and volume. Two independent operators measured orbital volume using each software package. In cases of medial orbital wall fractures, axial scans were used, while in cases of inferior and combined inferior-medial fractures, coronal reformed scans were used. The bony orbit on each scan was measured using the cursor to trace the orbital wall on the screen. On the axial CT scans, the anterior orbital boundary was defined by a straight line connecting the medial and the lateral orbital rims, and the regions lacking a bony boundary (ie, superior orbital fissure, inferior orbital fissure, lacrimal fossa, and optic canal) were traced with a straight line (Figure 1). On the coronal CT scans, the anterior border was determined as the CT slice in which 50% of the inferior orbital rim was visible, with the posterior limit being the orbital apex (Figure 2). In the case of missing bone of the lateral orbital wall (owing to the lateral wall being out of plane) on coronal CT scans, a line was drawn similar to that of the closest slice in which the whole orbital bone was seen and was used to demarcate the extent of the orbital volume (Figure 3). The areas of these outlines were measured on each scan and summed for orbital volume. To reduce measurement errors, the bony orbit area on each scan was measured twice, with at least a 1-week interval, and then averaged, and the scan images were magnified to enhance accuracy. In cases of obscure lining, the former and the next slides were referenced. The volume of the fracture was measured as the discrepancy in volume between the fractured and the normal contralateral orbital volumes.