This is sagging and eversion of the lower eyelid.
The most common cause is old age. Senile ectropion is frequently bilateral and results from a natural loss of muscle tone and orbital fat.
Cicatricial ectropion results from scarring of the skin, for example following trauma, especially burns, or irradiation for a rodent ulcer affecting the eyelids.
Less commonly, a paralytic ectropion results from a facial nerve palsy resulting in a flaccid orbicularis oris muscle.
Presentation is with epiphora and irritation. Tears overflow as a result of disturbance to drainage through the lower punctum which requires close apposition to the globe. Irritation results from the constant flow of tears over the lower lid. Infection of the exposed conjunctivitis may produce keratitis.
Treatment is with control of any secondary infection and surgical correction of the underlying structural deformity.