A Delphi Study on Developing an Eyebrow Shape Matching Guideline Considering Face Shape and Mask-Wearing

The eyebrow is one of the decisive elements in terms of facial impression, and compatibility with the face shape has been a key point in the beauty field. Since the COVID-19 pandemic, wearing masks to cover the lower part of the face has become a daily habit. Although there have been times when masks were not worn, the influence of the masked face on how facial impressions are formed has remained strong. However, the knowledge on which type of eyebrow to wear with which shape face has remained as the practitioners’ experience and there has been no design criteria for the eyebrows. This study developed an expert-consensus-based guideline for matching eyebrow shapes with face shapes and for mask-wearing situations. A three-round of modified Delphi survey was conducted with the beauty experts (16 participants in Round 2 and 17 in Round 3). The consensus was measured by content validity ratio, degree of consensus, and degree of convergence. Out of 54 items, 42 items (77.8%) reached consensus, and all of the items had stable responses (CV < 0.5) and significant panel agreement (Kendall’s W = 0.467, p < .001). The results showed that there was a consistent matching principle of complementing the face shapes, i.e., arched for square, straight for long, and angular for round faces, whereas standard faces could be matched with various shapes of eyebrows. In addition, under the mask-wearing situations, a more refined design taking into account of eye makeup, types of masks, and eyewear, etc. was necessary. The results of this study could be used as the knowledge base for developing deep-learning-based eyebrow recommendation systems.