Entropion & Ectropion

Overview

Entropion is inward rotation of the eyelid margin toward the globe; ectropion is outward rotation away from it. In both, the margin itself is displaced, which is what separates them from trichiasis: there the margin sits in normal position but individual lashes point inward and rub the ocular surface (see the eyelash disorders page). Each condition splits into four mechanistic subtypes. Involutional (age-related) and cicatricial (scarring) apply to both; spastic is unique to entropion, paralytic to ectropion. The subtype, not the diagnosis alone, determines the operation. A procedure that tightens horizontal laxity does nothing for a scarred posterior lamella, and a lamellar graft does nothing for pure laxity.

Entropion

Involutional Entropion

Involutional entropion is the most common form and occurs almost exclusively in elderly patients. Three age-related changes combine to produce it: horizontal eyelid laxity, disinsertion or attenuation of the lower lid retractors, and override of the preseptal orbicularis oculi over the pretarsal orbicularis during lid closure. The orbicularis override is the direct mechanical trigger. As the preseptal fibers slide up and over the pretarsal fibers, they push the margin inward. This happens in the lower lid because it lacks the rigidity the upper lid's larger tarsal plate provides, leaving it more exposed to the effects of laxity.

Since the underlying problem is laxity plus retractor disinsertion, definitive repair addresses both at once: the lateral tarsal strip procedure shortens and reanchors the lateral lid to the orbital rim to correct laxity, combined with lower lid retractor repair for the second defect.

Cicatricial Entropion

Cicatricial entropion results from scarring and contracture of the posterior lamella, specifically the tarsal (palpebral) conjunctiva, which shortens and rotates the margin inward. Classic causes are ocular cicatricial pemphigoid, chemical burns, and trachoma. Trachoma produces chronic follicular conjunctivitis that fibroses the upper tarsal conjunctiva, so trachomatous cicatricial entropion classically involves the upper lid, unlike the lower-lid-predominant involutional form. A traditional surgical option here is the Wies procedure: a transverse blepharotomy with marginal rotation sutures that evert the margin. The World Health Organization now calls this approach bilamellar lid margin rotation.

Spastic Entropion

Spastic entropion follows involuntary contraction (spasm) of the orbicularis oculi, usually provoked by ocular surface irritation or postoperative inflammation. The rotation it produces is transient and intermittent, not a fixed structural problem. Because the mechanism is muscular overactivity rather than laxity or scarring, measures that reduce orbicularis tone, including botulinum toxin injection (see the eyelid anatomy page), have a role here they don't have in the other subtypes.

Congenital Entropion and Epiblepharon

Congenital entropion is rare and different from the forms above: the lid margin itself is inverted from birth, almost always in the lower lid, most likely from dysgenesis or disinsertion of the lower lid retractors. It does not resolve on its own and needs surgical correction to prevent ongoing corneal injury.

Epiblepharon is far more common and easy to mistake for it. A horizontal fold of skin and orbicularis overrides the lid margin and pushes the lashes against the globe, but the margin position stays normal. It is most frequent in Asian infants and children, usually affects the lower lid, and often fades as the facial skeleton grows, so observation is reasonable unless the cornea shows damage.

Ectropion

Involutional Ectropion

Involutional ectropion mirrors involutional entropion: age-related laxity of the canthal tendons, tarsus, and orbicularis muscle lets the lower lid fall away from the globe. It is the most common form of ectropion in older adults. As with its entropion counterpart, horizontal lid-tightening surgery works well, and the lateral tarsal strip is again first-line, favored for its durability and low complication rate.

Cicatricial Ectropion

Cicatricial ectropion results from vertical shortening of the anterior lamella (skin and orbicularis), most often from burns, chronic dermatitis, or trauma, which pulls the margin away from the globe. The defect here is a shortage of anterior lamellar tissue, not horizontal laxity, so correction requires vertical lengthening, typically a skin graft or flap, rather than tightening alone.

Paralytic Ectropion

Paralytic ectropion follows facial nerve (CN VII) palsy. Orbicularis weakness removes the muscle's normal apposition force against the globe, and the lid falls away. The same weakness usually produces lagophthalmos alongside the ectropion, and the combination puts the eye at real risk of exposure keratopathy. Management includes aggressive ocular surface lubrication in addition to any surgical support of the lid.

Exam Findings and Complications

The key bedside test for both entropion and ectropion is the snap-back test: the lower lid is pulled down and away from the globe, then released, and its speed of return to normal apposition is observed without letting the patient blink. Failure to snap back promptly indicates significant horizontal laxity and supports a lid-tightening approach such as the lateral tarsal strip.

For entropion specifically, a useful temporizing measure while definitive surgery is planned is placement of Quickert (Quickert-Rathbun) sutures: temporary everting sutures placed through the lower lid that mechanically correct the inward rotation until permanent repair can be done.

Persistent entropion carries real corneal risk. Chronic lash-globe contact from the inturned margin can cause corneal abrasion, erosion, or ulceration, and an uncorrected malposition can progress to scarring and permanent vision loss.

High-Yield Pearls

• Involutional entropion = horizontal laxity + retractor disinsertion + orbicularis override, lower lid, elderly.
• Spastic entropion = orbicularis spasm from surface irritation or post-op inflammation; transient, not structural.
• Paralytic ectropion = CN VII palsy → loss of orbicularis apposition force, often with coexisting lagophthalmos.
• Snap-back test quantifies horizontal lid laxity at the bedside for either condition.

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