A simple, rapid, and reproducible method for producing high quality tomograms of the optic canals is described. The advantages observed in a clinical study of 72 canals include the ability to distinguish between the orbital and the cranial ends of the canal. In addition, obscured portions of the canal may be visualized in the tomographic section. Other advantages include the resolution of minimal abnormalities as hairline fractures and the localization of abnormalities seen on the plain film views. This method has proven useful to clinicians who analyze pathologic processes involving the optic canals.
Trokel SL, Potter GD. Hypocycloidal Tomography of the Optic Canal. Arch Ophthalmol. 1969;81(6):797–803. doi:10.1001/archopht.1969.00990010799008