Generally speaking, people's eyes are divided into white eyeball, black eyeball and red tissue in the inner corner of the eye. The ideal eye is that the inner corner of the eye can see about 50-80% red tissue.

The epicanthus refers to a vertical fold in front of the epicanthus, covering the epicanthus, so that the angle of the epicanthus is smaller than that of people without epicanthus. It also blocks part of the field of vision, so that two-faced people can only form a "half pair", which affects the beauty of the eyes.