Computed Tomographic Measurments of the Orbit and Proptosis in Koreans

ABSTRACT

The orbit has roughly the shape of a quadrilateral pyramid whose base corresponds to the orbital margin, and whose apex is the bar of bone between the optic foramen and the medial end of the superior orbital fissure. The orbital dimensions can be measured by plain X-ray or computed tomography. Plain X-ray of the orbit may be difficult for the non-radiologist to identify the measurement landmarks and interpret, whereas computed tomography allows more precise analysis by imaging soft tissue relationships to surrounding orbital bones. Measurement of the orbital dimensions and proptosis using CT does not only contribute to the diagnosis of specific pathologic processes, but also guide the ophthalmologist in planning appropriate medical and surgical management. One hundred and three orbital CT films of Korean adults were measured. The results were as follows The average orbital width was 38.09 +/- 2.82mm, orbital height was 35.47 +/- 2.28mm, orbital index was 93.80 +/- 6.70, orbital depth was 42.67 +/- 3.56mm, interorbital distance was 24.97 +/- 2.25mm, extraorbital distance was 97.38 +/- 5.14mm and proptosis was 14.28 +/- 3.49mm.