The epicanthal fold is a small web of tissue overlapping the nasal corner of the eye. It is seen in both Asian and Occidental eyelids, but is much more common and distinctive in Asian eyelids, where it seems to be present to at least some degree in almost every patient. The presence of an epicanthal fold is normal in people of Asiatic descent. An epicanthal fold is also
common in children with Down syndrome. Epicanthal folds may also be seen in young children of any race before the bridge of the nose begins to elevate.
The fold may vary from hardly-noticeable to well-developed. It is typically most prominent during childhood, but often changes shape and diminishes in size with age as the developing bridge of the nose gains more height and pulls the skin away from the eye.
The reason for the increased prevalence and prominence of the epicanthal fold on the Asian eyelid has not been thoroughly elucidated, but undoubtedly the explanation lies in the many variations of the complex anatomy of the multi-contoured area of skin, muscle, and tendon located between the bridge of the nose and the inner corner of the eye.
Terminology used to describe the anatomic variations in the epicanthal folds is confusing and of limited clinical relevance. It is more helpful to speak of the fold as minimal, moderate, or prominent.
Epicanthoplasty is occasionally undertaken to soften the appearance of an especially prominent fold. Available procedures are not without risk and are best reserved for folds with substantial cosmetic impact.