Wang Tim T, Wessels Louis, Hussain Gazi, Merten Steve
Department of Plastic, Reconstructive, and Hand Surgery, Concord Hospital, Sydney, Australia.
Aesthet Surg J. 2017 Apr 1;37(4):375-385. doi: 10.1093/asj/sjw271.
Facial symmetry is intimately correlated with attractiveness. Perfect facial symmetry is disconcerting and a degree of facial asymmetry is considered normal. There is a lack of data on the limits of normality across facial subunits.
This systematic review aims to establish categories of facial asymmetry perception for facial aesthetic units by establishing a discriminative threshold of "deformity perception" across facial subunits and a threshold for intervention (unacceptable asymmetry).
A review of the literature was performed across Medline and Embase databases using OvidSP. All prospective studies evaluating the perception of progressive facial asymmetry in laymen or clinicians using a two- or three-dimensional model were included. Studies that did not evaluate rates of perception at varying degrees of asymmetry were excluded as these did not allow for the identification of a perceptive threshold.
Each facial feature possesses a unique threshold of perception defined by an abrupt, statistically significant increase in detection. Asymmetry of the eyelid position at rest is the most sensitive facial feature (perceptive threshold, 2 mm) (P < 0.02). This is followed by deviations of the oral commissure (3 mm) (P < 0.001), brow position (3.5 mm) (P < 0.001), nasal tip deviation (4 mm) (P < 0.001), and chin deviation (6 mm) (P < 0.001). Desire for surgery for worsening deformities beyond the intervention threshold is characterized by an exponential, rather than linear, correlation.
Categories of facial asymmetry perception establish a framework to counsel patients with facial asymmetries, and are a valuable adjunct to clinical judgment in the management of static and dynamic facial deformities.
面部对称性与吸引力密切相关。完美的面部对称性令人不安，一定程度的面部不对称被认为是正常的。目前缺乏关于面部各亚单位正常范围界限的数据。
本系统评价旨在通过确定面部各亚单位“畸形感知”的鉴别阈值和干预阈值（不可接受的不对称），建立面部美学单位的面部不对称感知类别。
使用OvidSP在Medline和Embase数据库中进行文献检索。纳入所有使用二维或三维模型评估外行人或临床医生对渐进性面部不对称感知的前瞻性研究。未评估不同程度不对称感知率的研究被排除，因为这些研究无法确定感知阈值。
每个面部特征都有一个独特的感知阈值，其定义为检测率突然出现具有统计学意义的增加。静息时眼睑位置不对称是最敏感的面部特征（感知阈值为2毫米）（P<0.02）。其次是口角偏差（3毫米）（P<0.001）、眉位偏差（3.5毫米）（P<0.001）、鼻尖偏差（4毫米）（P<0.001）和下巴偏差（6毫米）（P<0.001）。对于超过干预阈值的畸形加重，手术意愿的特点是呈指数而非线性相关。
面部不对称感知类别为咨询面部不对称患者建立了一个框架，是静态和动态面部畸形管理中临床判断的有价值辅助手段。
