Measurement of Eye Size Illusion Caused by Thickness of Eyeliner on Double-Eyelid Eyes

Abstract

Eyeliner is one of the makeup methods that enhances the attractiveness of female by a geometric illusion that makes the eyes appear larger. Eyeliner has no fixed shape, and its thickness and length can be freely adjusted. In this paper, we experimentally verify the relationship between thickness of eyeliner and the perceived eye size. In addition, by examining the sense of incongruity of the eyeliner, we clarify the optimal thickness of eyeliner as makeup to make the eyes appear larger. The results showed that the thicker eyeliner, the larger the eyes were perceived to be. However, the excessive thickness of eyeliner increased the sense of incongruity and reduced the illusion effect. There were gender differences in the results of these experiments. For male, thickness of eyeliner had a significant effect on the perception of eye size, while for female it had no significant effect.