In this study we evaluated the location and shape of the optic canal using computed tomography (CT) for diagnosis and treatment of posterior orbital diseases.

Fifty patients, who had received a facial bone CT between November 2012 and June 2013 at Korea University Hospital were included in the present study. The location and shape of the optic canal was evaluated using 9 parameters on CT (P1: nasal bone tip; P2: middle point of tuberculum sellae; P3: root of columella nasi; P4: orbit end of the optic canal; P5: cranium end or the optic canal; P6: P1's projection on L2; L1: line that links P1 and P2; L2: goes through P3 and parallel to L1; L3: bisector of right and left and goes through P1).

The distance between P3 and P4 was 81.5 mm and 75.6 mm in males and females, respectively ( p = 0.001). The distance between P3 and P5 was 88.5 mm and 82.1 mm in, males and females, respectively ( p = 0.001). The width of the orbital end and cranium end of the optic canal, the length of the optic canal was 2.4 mm, 4.1 mm, 10.9 mm in males and 2.3 mm, 3.6 mm, 10.2 mm, in females, respectively.

By determining the location and shape of the optic canal, these results can facilitate endoscopic approaches to diagnose and manage posterior orbital diseases as well as manage and prevent disorders associated with the optic canal.