Single eyelids, also known as monolids, are a type of eyelid structure where there is no visible crease. This feature is common in various ethnic groups, particularly among individuals of East Asian descent. Single eyelids can create a smooth appearance across the eyelid, which some people find aesthetically appealing. The absence of a crease can affect how makeup is applied and how the eyes appear in photographs. Many people with single eyelids use specific techniques to enhance their eyes, such as eyeliner and eyeshadow application methods tailored to their eyelid shape.