Whether eye canting in patients with asymmetric dento-maxillofacial deformities is the result of anatomical asymmetry or a compensatory head position remains controversial.

This cross-sectional study aims to verify whether eye canting is correlated with craniofacial skeletal asymmetry.

This study was performed by measuring the computed tomographic scans of 223 patients with dento-maxillofacial deformities in Mimics 21.0 software. First grouping was determined based on the intersection angle between the line passing through bilateral lateral canthus point and Frankfurt horizontal plane, and final grouping was based on measurements of the pregroups.

The patients were finally categorized into three groups: symmetry group (n = 163), asymmetry subgroups 1 (n = 33) and asymmetry subgroups 2 (n = 27). The results of multiple linear regression and comparisons among groups suggests the presence of orbital skeletal asymmetry in patients with eye canting and the eye canting is partly increment dependent of orbital skeletal asymmetry when using bilateral ears as the reference. The result also reveals that there is a greater angle between the line through bilateral ocular landmarks and the line through the bilateral ear landmarks in patients with ocular canting compared to patient without eye canting.

Patients with asymmetric dento-maxillofacial deformities and with eye canting have vertical asymmetry of the orbital and cranial skeletal landmarks. These symmetry differences between the eyes and ears may affect the overall craniofacial symmetry after orthognathic surgery