Three-dimensional photogrammetry to evaluate facial asymmetry among young population
10.3760/cma.j.cn114453-20200619-00376
- VernacularTitle:三维摄影测量技术评估青年人群面部不对称性
- Author:
Yuming CHONG
1
;
Xinyu LIU
;
Xiaojun WANG
;
Jiuzuo HUANG
;
Nanze YU
;
Xiao LONG
Author Information
1. 中国医学科学院北京协和医院整形美容外科 100032
- Keywords:
Facial asymmetry;
Photogrammetry;
Imaging, three-dimension;
Young adult
- From:
Chinese Journal of Plastic Surgery
2021;37(1):40-48
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To evaluate facial asymmetry among Chinese young population via three-dimensional photogrammetry.Methods:Young subjects were recruited in Beijing from May to December in 2017. Three-dimensional facial images were obtained by VECTRA H1 camera. The images were exported to Geomagic Wrap 2017. Soft tissue landmarks were identified, and a coordinate system was built on every image. The face was divided into upper, middle, and lower part by the horizontal plane passing the exocanthion and the horizontal plane passing the cheilion. On the coronal plane, the distances between the midsagittal plane and the homogeneous landmarks located on the right and left hemifaces as well as bilateral palpebral fissure height were computed. In terms of facial depth, facial depth parameters located on the right and the left hemifaces were computed. There was a total of 13 parameters. Parameters on one hemiface were compared with those on the other hemiface using paired t-test. Mean absolute difference (MAD) and asymmetric rate (AR) were computed. Finally, we compared the result on men to the result on women via t-test. P<0.05 was considered statistically significant. Results:There was a total of 122 young subjects, 60 men (25.1±3.8 years old) and 62 women (27.3±4.3 years old). (1) On coronal plane, among males, the difference between bilateral tragion and midsagittal plane and the difference between bilateral cheilion and midsagittal plane were statistically significant( P<0.05); among females, the difference between bilateral exocanthion and midsagittal plane, the difference between bilateral palpebrale superius and midsagittal plane, and the difference between bilateral tragion and midsagittal plane were statistically significant ( P<0.05). Among bilateral landmarks (except for palpebral fissure height), the MAD of the distance between bilateral exocanthion and midsagittal plane was the smallest, (1.00±0.88) mm (AR=2.1%) and (1.08±0.79) mm (AR=2.4%) among men and women, respectively ( t=0.541, P=0.589). The MAD of the distance between lateral tragion and midsagittal plane was the largest, (3.45±2.54) mm (AR=4.6%) and (2.89±2.86) mm (AR=4.1%) among men and women, respectively ( t=-1.149, P=0.253). (2) In terms of facial depth, among both males and females, the difference between all bilateral facial depth parameters was statistically significant ( P<0.05). The MAD of the distance between the pogonion and bilateral tragion was the largest, (2.62±1.69) mm (AR=1.8%) and (2.45±1.69) mm (AR=1.8%) among men and women, respectively ( t=-0.491, P=0.625); the MAD of the distance between the glabella and bilateral tragion was the smallest, (1.77±1.25) mm (AR=1.4%) and (1.91±1.54) mm (AR=1.6%) among men and women, respectively ( t=0.587, P=0.558). Conclusions:Facial asymmetry is universal among Chinese young population. The MAD does not exceed 3.5 mm. Upper one-third face has higher symmetry while lower one-third face has lower symmetry.
