Not to be confused with the epicanthal fold, epiblepharon is an abnormal congential condition of the lower eyelid in which loose skin forms a fold sitting high up and immediately in front of the lashes.
Most usually located along the inner half of the lower lid, it may also extend across the full lid in some cases. When the eye looks down or sometimes even when looking straight ahead, the lashes can be forced inward and rub on the surface of cornea.
Found more often in those of Asian descent, epiblepharon is usually noted during early childhood and then be outgrown as the internal anatomy of the lower lid becomes more mature. However, this condition may persist into adult life and cause intermittant or even constant irritation.
In cases where epiblepharon is severe and the lashes are causing too much eye irritation, light sensitiviy, and tearing, surgery may be required to remove and/or tack down the skin forming the abnormal fold in a manner not unlike that used in some less-invasive versions of upper lid double eyelid surgery. The scar usually fades to nearly unnoticeable over several years.
While epiblepharon can be present in adults as well, most cases of in-turned lower lids and lashes in later life are more serious. Known as "entropion," the entire lid can become inverterted.
Bothersome epiblepharon in seldom seen in young children of European descent, who instead often show a well-defined lower lid "crease" stabilizing the skin. Although these temporary indentations later weaken and disappear, epiblepharon does not then follow.
The anatomical mechanism allowing lower eyelid epiblepharon is related to the same anatomical variations seen in the upper lids of people with Asian eyelids lacking a crease. Without natural tissue adhesion between the eyelid's closing (orbicularis) muscle and deeper support structures, the more mobile skin and muscle are able to more easily float downward in the upper lid and upward in the lower lid.
When found in the adult lower eyelid but not associated with eye irritation, some people still elect to undergo surgical correction of epiblepharon for cosmetic reasons.