The most common form of lower eyelid entropion (involutional entropion) develops from a weakening and stretching of the tendons supporting the eyelids to the orbital rim of bone. In addition, a tendon-like sheath below the tarsal plate tears or stretches, thus allowing the unstable eyelid to rotate inward against the eye. Pain from lashes and skin rubbing against the cornea can be severe, and the risk from entropion to vision is immediate.
Another form of entropion (cicatricial entropion) is associated with scarring from trauma or infection on the back lining of the eyelid and/or within the internal structure of the eyelid. While uncommon in the United States, this variant of entropion is a leading cause of blindness in underdeveloped countries.
Surgical correction on the more common type of entropion entails rotating the lid margin back to its normal position by tightening both the canthal tendons and the tendon-like sheath. In cicatricial entropion, grafting of tissue from donor sources and internal eyelid rearrangement may be needed.
