Repositorio Académico

Determination of the orbital volume has significance in cases such as facial injuries and lens implants where it is necessary to restore the normal position of the structures, since providing the patient with a volume-deficient orbit may result in enophthalmos. The aim of this study is to assess the volume of the orbit by using the Cavalieri's principle supplemented with sequential analysis of CT images on the computer screen. We conducted a series of CT images with a thickness of 1mm on 10 human skulls. After selection, initially random and then sequential, images were analyzed on a computer screen with a mesh test chart to determine orbital area. Once having identified both area and thickness, we measured the volume of segments, and the total volume of the orbit was extrapolated by using a mathematical formula based on the Cavalieri's principle. Results were compared with the actual volume obtai-ned by the displacement of fluid from printouts of the orbits. The result of this comparison suggests that the method is statistically reliable when considering that we assessed seven images of a randomly chosen orbit and then in a known sequence with a straightforward technique for orbital volume estimation.