Normally when you blink, your eyelids distribute tears evenly across your eyes, keeping the surfaces of the eyes lubricated. These tears drain into small openings on the inner part of your eyelids (puncta).

If you have ectropion, your lower lid pulls away from your eye and tears don't drain properly into the puncta. The resulting signs and symptoms can include:

• Watery eyes (excessive tearing). Without proper drainage, your tears may pool and constantly flow over your eyelids.
• Excessive dryness. Ectropion can cause your eyes to feel dry, gritty and sandy.
• Irritation. Stagnant tears or dryness can irritate your eyes, causing a burning sensation and redness in your eyelids and the whites of your eyes.
• Sensitivity to light. Stagnant tears or dry eyes can irritate the surface of the cornea, making you sensitive to light.

Ectropion can be caused by:

• Muscle weakness. As you age, the muscles under your eyes tend to weaken, and tendons stretch out. These muscles and tendons hold your eyelid taut against your eye. When they weaken, your eyelid can begin to droop.
• Facial paralysis. Certain conditions, such as Bell's palsy, and certain types of tumors can paralyze facial nerves and muscles. Facial paralysis that affects eyelid muscles can lead to ectropion.
• Scars or previous surgeries. Skin that has been damaged by burns or trauma, such as a dog bite, can affect the way that your eyelid rests against your eye. Previous eyelid surgery (blepharoplasty) can cause ectropion, particularly if a considerable amount of skin was removed from the eyelid at the time of surgery.
• Eyelid growths. Benign or cancerous growths on your eyelid can cause the lid to turn outward.
• Genetic disorders. Rarely is ectropion present at birth (congenital). When it is, it's usually associated with genetic disorders, such as Down syndrome.

Factors that increase your risk of developing ectropion include:

• Age. The most common cause of ectropion is weakening muscle tissue associated with aging.
• Previous eye surgeries. People who have had eyelid surgery are at higher risk of developing ectropion later.
• Previous cancer, burns or trauma. If you've had spots of skin cancer on your face, facial burns or trauma, you're at higher risk of developing ectropion.

Ectropion leaves your cornea irritated and exposed, making it more susceptible to drying. The result can be abrasions and ulcers on the cornea, which can threaten your vision.