An aging lower eyelid can become lax and rotate outward. This allows the inner side of the eyelid to be exposed to air, which it is not used to. The eyelid becomes red and the eye will become irritated and tear excessively.
Conditions such as aging, prior surgery or trauma can lead to weakening of the lower eyelid. If the lower eyelid weakens enough, the lid may rotate outward. This condition is known as ectropion. Ectropion can cause chronic eye irritation and tearing because the eye is constantly exposed to air.
Surgery to correct ectropion generally involves tightening the lower eyelid, known as canthoplasty. Severe cases may also require elevating the cheek to reduce the gravitational pull of the cheek on the lower lid.
This can be repaired by tightening the lower lid using a canthoplasty. Severe ectropion may require elevation of the soft tissue of the cheek in order to support the lower eyelid.