The supporting structure of the lower eyelid may be likened to a hammock, with a cartilage-like central stiffener element (tarsal plate) attached by two tendons (canthal tendons) to the socket bone on either side of the eye. If the tendons become stretched due to wear-and-tear or from trauma or even other eyelid surgery, the lid may lose its normal adherence to the eye surface and sag outward, a condition known as ectropion.
In the presence of ectropion, wind and dust may dry out and irritate the delicate tissue lining the back of the exposed eyelid. Tearing develops when the tear duct drain on the edge of the eyelid drifts away from the eyeball and can no longer pick up the moisture. Eventually, an eye with ectropion may develop scarring.
Ectropion eyelid surgery is designed to tighten the stretched tendons and shorten the stretched lid. If the tendons have become too shredded, an entirely new means of support may be fashioned by borrowing from nearby healthy tissues.
Cicatricial ectropion indicates a condition in which the skin below the eyelid has been scarred and tightened, thus exerting a constant downward pull on the eyelid support system. In such cases, a skin graft may be necessary.
