When the the eyelid suffers a loss of tone, two disorders may occur as a result: ectropion or entropion.
Ectropion is where the lower eyelid droops away from the eye and turns outwards. As a result, the inner surface of the lid becomes exposed, irritated, and thickened. It occurs primarily in elderly people and is aggravated by excessive tearing. The wiping away of tears from the lower lid makes the lid droop even further. The drooping causes burning and irritation.
Entropion is an inward turning of the lower lid margin against the eyeball. Patients complain of the lashes rubbing against the eye, which can cause damage to the cornea by ulceration and infection. The basic causes are:
- Age: The eyelid is held in good position by two sets of muscles. One pulls the eyelid away from the eyeball, while the other turns the lid toward the eyeball. When an imbalance in this system favors the set pulling toward the eye, an entropion results. This imbalance is a natural consequence of the aging process.
- Scarring: This may result from many different diseases or injuries again causing the characteristic imbalance in the muscles controlling the lower lid.
- Congential: An entropion from birth is very rare.
- Spasticity: Here the eyes are vigorously closed because of inflammation, eye surgery or injury. The lower lid may turn on itself due to this strenuous attempt at closure.
In most cases, treatment for both disorders is surgical—although, eyedrops and ointments may sometimes be used to manage symptoms.
The purpose of surgery is to strengthen the muscles that draw the lid away from the eye. Sometimes a better approach is to tighten up the whole lid to put it in better position. Each patient is different, and many factors are taken into consideration in planning the correct surgical procedure.
Surgery is done with a local anesthetic as an outpatient procedure and is well tolerated. Potential problems with this surgery include:
- Over correction with consequent eversion of the lower lid (this usually corrects itself within a few weeks)
Recurrence rates have improved dramatically with better understanding of the abnormal muscles involved and better surgical techniques.