Monolid

Monolid refers to an eyelid shape in which the upper eyelid lacks a well-defined supratarsal crease, giving the eyelid a smooth, uninterrupted contour when the eye is open. The term is often used in contrast with the double eyelid, where a visible crease creates a distinct fold above the lash line. Monolid eyelids are common among many East Asian populations and can also be observed in individuals of other backgrounds. The appearance can range from a very shallow crease to a smooth lid with no crease at all.

Developmental factors are genetic and multifactorial; the feature is typically congenital but may change with age, weight changes, or eyelid fat distribution, sometimes becoming more or less creased. It is a normal anatomical variation rather than a medical condition. It is not generally associated with impaired vision.

Distinctions: there are subtypes, including true monolids with no crease and low-crease lids where a shallow crease is present or only visible in certain expressions. Some individuals may have epicanthic folds which can overlay the eye but are not the same as the lid crease.

Cosmetic considerations: some people with monolid may seek blepharoplasty to create a double eyelid crease, or use non-surgical methods such as eyelid tape or glue to simulate the crease. Variation in eyelid appearance should be respected, and preferences differ across individuals and cultures.

See also: double eyelid, blepharoplasty, epicanthic fold.