Introduction
The aim of this controlled study was to analyze the degree and localization of 3-dimensional (3D) facial asymmetry in adult patients with cleft lip and palate (CLP) compared with a control group and its impact on the visual perception of faces.
Methods
The degree of 3D asymmetry was analyzed with a novel method without landmarks in 18 adults with complete unilateral CLP and 18 adults without congenital anomalies. Furthermore, the CLP and control faces were rated for appearance, symmetry, and facial expression by 30 participants.
Results
The results showed that adults with CLP had significantly greater asymmetry in their facial soft tissues compared with the control group. Moreover, the lower face, and particularly the midface, had greater asymmetry in the CLP patients. The perceptual ratings showed that adults with CLP were judged much more negatively than those in the control group.
Conclusions
With sophisticated 3D analysis, the real morphology of a face can be calculated and asymmetric regions precisely identified. The greatest asymmetry in CLP patients is in the midface. These results underline the importance of symmetry in the perception of faces. In general, the greater the facial asymmetry near the midline of the face, the more negative the evaluation of the face in direct face-to-face interactions.
Editor’s summary
The authors of this study analyzed the amount and localization of 3D facial asymmetry in 18 adults with repaired cleft lip and palate (CLP) compared with 18 unaffected controls (matched for sex but not age). The impact of residual facial deformity on visual perception was tested with 30 volunteer raters (laypeople). They evaluated facial cutout photograph views, masked to eliminate ears, hair, and peripheral features, on a 9-point scale for appearance, symmetry, and positive or negative facial expression. The extent of 3D facial asymmetry was measured by using an optical 3D surface scan of the patients’ surfaces and then superimposing the 3D data on mirror images of the face with triangulated polygon meshes. Quantitative measurements were analyzed by determining the distances between the original and mirror images. The face was divided into 2 parts—midface and lower face—to compare indexes of facial asymmetry in these parts.
The results showed a higher soft-tissue asymmetry index in postoperative adult CLP patients compared with the controls. The most asymmetry was in the midface of the CLP patients compared with the controls. These results underline the importance of symmetry in the perception of facial esthetics. In general, the greater the asymmetry near the midline of the face, the more negative the evaluation by people in face-to-face interactions. Although these conclusions fail to tell us anything we didn’t already know, the use of 3D technology makes it much easier to evaluate the location of such asymmetries. This technology also provides a convenient mechanism for evaluating the public’s perception of facial appearance, symmetry, and expression.
