According to normal physiological development, normal eyelids are single eyelids, and double eyelids can be said to be a defect of eyelids. As can be seen from the pictures of ladies in the Tang Dynasty, all beautiful women are phoenix eyes (single eyelid phoenix eyes); If it is a double eyelid, it seems to be a defect at that time. In layman's terms, it is a scar, so it is disfigured.

Nowadays, plastic surgery is all about pulling (cutting) double eyelids, that is, artificially creating defects. Of course, people nowadays think that double eyelids look good.