An alignment device to facilitate taking optic canal radiographs is described. It is designed to be used as an accessory for standard radiographic head units. The device has proven to be an extremely rapid method for the preparation of symmetrically placed optic canal radiographs.
Trokel SL, Potter GD. A Method of Optic Canal Radiography. Arch Ophthalmol. 1970;83(6):698-699. doi:10.1001/archopht.1970.00990030698004