Perception of symmetry in the face.

One purpose of this study was to assess the perception of (a)symmetry of the face by professionals, lay persons, and sculptors using the ratio estimation scale technique. The other purpose was to compare the perceptions of the faces of patients with those of the controls. Three groups of examiners were involved in this study: lay persons (n = 37), professionals (5 orthodontists and 11 surgeons, n = 16), and sculptors (n = 22). The total number of examiners was 75. All groups agreed on the ordering of the patients according to the severity of the affliction. The stage of asymmetry by group identity interaction effect (lay persons, professionals, and sculptors) was significant (P = 0.004). The between-examiner consensus was high for the original asymmetrical photograph, but the groups diverged further and further over the next steps. The subject identity by stage of asymmetry interaction effect was significant (P = 0.001), whereas the examiner's main effect was not. For all patients, each step resulted in a smaller need for treatment. A need for treatment was not found for any of the control subjects, with 1.5 being the highest need for treatment score for controls. The subject identity effect (patient/control) was significant (P < 0.001). Even at step 5 (the reconstructed symmetrical photograph), all patients were perceived to have an inferior appearance to that of control subjects. It is possible to obtain reliable assessment using the ratio estimation scale technique. Professionals, lay persons, and sculptors have different perceptions of the degree of asymmetry but not of the need for treatment. All patients were scored as asymmetrical compared with controls. Asymmetry of the patients was obvious for all the examiners.