Entropion is a disorder in which the eyelid margin turns inward toward the eyeball, causing the eyelashes or inward-turned eyelid skin to continually touch the eye surface and leading to corneal epithelial damage, clouding, a foreign-body sensation, tearing, and similar symptoms. If the lashes keep touching the eye and this is left untreated, the corneal epithelial damage becomes chronic and can eventually impair vision.
Eyelid entropion includes congenital epiblepharon and acquired involutional entropion, cicatricial, spastic, and mechanical types. Congenital epiblepharon is a condition in which the eyelashes touch the eye surface because the anterior lamella (skin and orbicularis muscle) is naturally excessive compared with the posterior lamella (tarsus). Involutional entropion is mainly caused by laxity of the eyelid support tissues. The names are similar, but the underlying condition and choice of surgery are fundamentally different.
The goal of surgery is to permanently eliminate eyelash contact with the eye surface and to restore the corneal epithelium, improve vision, and reduce symptoms. Procedures are broadly classified into the suture method and the incision method (such as the Hotz procedure), while in age-related cases the standard is shortening of the support tissues.
Epiblepharon is congenital and refers to a condition in which excessive anterior lamella (skin and orbicularis muscle) causes the eyelashes to touch the eye surface. Entropion is a condition in which the entire eyelid margin turns inward toward the eyeball, and the age-related type is typical. Both are corrected with surgery, but the procedure selected differs according to the condition.
Entropion is classified into five types by cause. The table below summarizes the features of each type.
| Classification | Commonly seen | Mechanism | Main treatment |
|---|---|---|---|
| Congenital (epiblepharon) | Infants and the nasal side of the lower eyelid | Excess of the anterior lamella (skin and orbicularis oculi muscle) | Buried suture method and Hotz procedure |
| Involutional (degenerative) | Older adults and lower eyelid | Laxity of supporting tissues | Jones modification and LTS procedure |
| cicatricial | post-traumatic/post-burn | cicatricial contracture of the posterior lamella | mucosal grafting, etc. |
| spastic | associated with blepharospasm | abnormal contraction of the orbicularis oculi muscle | BTX → surgery |
| mechanical | anophthalmos/proptosis | loss of supporting structures | treatment of the underlying disease |
The following symptoms occur when the eyelashes or inward-turned eyelid skin touch the ocular surface.
Congenital (trichiasis): marked blinking in infants, reluctance to wash the face, conjunctival redness, discharge, and tearing are typical. The nasal side of the lower eyelid is often the most severe.
Age-related (involutional): the entire lower eyelid turns inward, and the eyelid skin, including the eyelashes, touches the ocular surface. Laxity of the tarsal supporting tissues is the cause, and symptoms may worsen when standing or closing the eyes.
Cicatricial: occurs when the posterior lamella of the eyelid scars and contracts after trauma, burns, chemical injury, or Stevens-Johnson syndrome. It is often accompanied by refractory corneal epithelial damage.
Spastic: often occurs together with blepharospasm, and strong spasms of the orbicularis oculi muscle pull the eyelid margin inward toward the eyeball.
Mechanical: Loss of support due to anophthalmia, phthisis bulbi, or orbital fat atrophy, or lower eyelid traction caused by proptosis.
Congenital entropion is common in infants and is said to occur more often in people of Asian descent. It is common on the nasal side of the lower eyelid, and some spontaneous improvement can be expected with age. However, cases with poor corrected vision in school-age children or younger are candidates for active surgery.
Age-related entropion accounts for most acquired entropion and is common in the lower eyelid of older adults. As the eyelid support tissues loosen with age, it progresses gradually and spontaneous improvement cannot be expected. The prevalence of symptomatic age-related entropion has been reported in Western studies to be about 2–3% among older adults7).
Cicatricial entropion occurs after trauma, burns, or chemical injury, and after trachoma it is a problem in endemic areas such as Africa. After Stevens-Johnson syndrome (SJS), bilateral and severe cicatricial entropion is common.
Congenital entropion can improve somewhat on its own with age. However, if corrected vision is below 1.0, or if there is corneal opacity or marked astigmatism, there is a risk of amblyopia, so surgery should be actively considered.
It is easy to see eyelashes touching the ocular surface, so diagnosis is usually not difficult. Fluorescein staining with a slit-lamp examination is used to confirm the distribution and severity of corneal epithelial damage.
For new-onset entropion in young or middle-aged adults, consider acquired causes such as trauma or inflammation. It is also important to distinguish it from trichiasis, in which some eyelashes grow in an abnormal direction, and distichiasis, in which there is an extra row of eyelashes. These conditions do not involve entropion of the eyelid margin, and the treatment approach differs.
The indication for surgery is determined comprehensively based on the following four items.
Decision for surgery in children: Entropion may improve with age, but in children of school age or younger with poor cases whose corrected visual acuity is below 1.0, surgery is actively recommended because of the risk of amblyopia.
Limits of eyelash epilation: If many eyelashes are touching the cornea, epilation alone has its limits. Because regrown eyelashes will contact the eye again, the definitive treatment is generally surgery.
In the early stage, temporary manual repositioning may be possible, but if the entropion persists and corneal epithelial damage becomes chronic, surgical treatment should be considered. For corneal epithelial damage, artificial tears and epithelial-repair eye drops (such as sodium hyaluronate eye drops) are used as adjunctive therapy.
Surgery for entropion in young patients is broadly divided into the suture method (buried suture method) and the skin incision method (Hotz procedure).
Buried suture technique (thread-through method)
Beads method: a non-incisional method using silk sutures. Can be performed as an outpatient procedure.
Nylon buried suture technique: without removing excess anterior eyelid lamella, the lash line is everted using only sutures. Simple and minimally invasive.
Limitations: the amount of correction has a limit, and recurrence is more likely in cases with a large amount of excess anterior lamella.
Incisional method (Hotz method)
Procedure: skin incision → removal of excess skin and orbicularis muscle → evert the anterior eyelid lamella including the lash line and suture it to the tarsus.
Indications: cases with insufficient correction using the buried suture method, and cases with large amounts of excess skin and orbicularis muscle.
Advantage: because the excess anterior lamella is physically removed, reliable correction can be achieved.
In a study comparing the nylon buried suture method and the Hotz method for surgical outcomes in congenital entropion, both procedures were shown to be effective6).
In involutional entropion, the pathology is laxity of the tarsal support tissues, and surgery is chosen to correct it. Surgery with the Hotz method alone does not match the pathology, so it is inappropriate.
The main procedures are shown in the table below.
| Procedure | Target | Features |
|---|---|---|
| Jones modification | Shortening of the lower eyelid retractor aponeurosis | Restoration of vertical support |
| Kakizaki method | Shortening of the lower eyelid retractor aponeurosis | Restoration of vertical support |
| Combined Wheeler modification-Hisatomi procedure | Shortening of horizontal support tissues | Correction of horizontal laxity |
| Lateral tarsal strip (LTS) procedure | Horizontal support tissue shortening | Widely used standard procedure |
Lateral tarsal strip (LTS) procedure is an operation in which the lateral end of the tarsal plate is cut and sutured to the periosteum of the lateral orbital rim, and it is widely used for involutional entropion. It is excellent for correcting horizontal laxity and is also commonly used for ectropion (outward turning of the eyelid)4).
Lower eyelid retractor aponeurosis shortening is represented by the Jones modification and the Kakizaki method. It shortens and reattaches the lax lower eyelid retractor aponeurosis, correcting the forward-upward displacement of the lower border of the tarsal plate1).
To further reduce recurrence, combining retractor aponeurosis shortening with horizontal shortening is considered effective3, 5). In studies comparing surgical outcomes, the lateral tarsal strip procedure has shown favorable long-term results2).
In early cases, botulinum toxin injection can relieve spasm of the orbicularis oculi muscle and improve entropion. In cases that do not improve with botulinum toxin, the condition is considered to include laxity of the lower eyelid retractor aponeurosis and separation of the adhesion between the orbicularis oculi muscle and the tarsus, and surgery similar to that used for involutional cases should be considered.
Some cases improve with appropriate wear of an ocular prosthesis and treatment of the eye or orbital disease. If entropion remains even after the cause is removed, eyelid repair surgery is planned.
The buried suture method is minimally invasive and can be performed in an outpatient setting, but there are limits to the amount of correction it can achieve. The incision method (Hotz method) removes excess skin and orbicularis oculi muscle to achieve reliable correction. For both, ending with slight overcorrection is the key to lowering recurrence. In involutional cases, shortening of the supporting tissues is necessary, and the Hotz method alone is not appropriate.
The following care is provided after surgery.
Some degree of relapse is inevitable after surgery. The recurrence rate is somewhat higher, especially in congenital entropion. Reoperation for recurrence due to undercorrection is not especially difficult, and it is important to explain the possibility of recurrence before surgery.
To prevent recurrence, the basic approach is to finish the operation with slight overcorrection so that the palpebral conjunctiva is mildly everted at the end of surgery.
In rare cases, overcorrection can cause eyelid ectropion. Mild ectropion may improve over time, but if it persists, additional surgery is needed.
If corneal epithelial damage remains after surgery, consider whether there is another cause such as trichiasis, or whether secondary infection has been ruled out.
There is always some degree of recurrence after surgery, and the recurrence rate is slightly higher, especially in congenital cases. Reoperation for recurrence due to undercorrection is not very difficult, so it is important to understand the possibility of recurrence before surgery. To reduce the recurrence rate, it is important to finish the operation with slight overcorrection.
Congenital epiblepharon is fundamentally caused by the anterior lamella (skin and orbicularis oculi muscle) being naturally excessive compared with the posterior lamella (tarsus). In infants and young children, the excess skin and loose attachment of the subcutaneous tissue cause the eyelid and eyelashes to touch the cornea. Excess of the anterior lamella is most prominent on the nasal side of the lower eyelid, and this area tends to be the most severe.
As a child grows, the facial skeleton develops and the balance between the anterior and posterior lamellae of the eyelid improves, so the condition may resolve naturally. However, surgery is needed when the excess anterior lamella is marked or when it does not improve by school age.
Two main mechanisms are involved in the development of age-related entropion.
Laxity of the lower eyelid retractor aponeurosis: With aging, the lower eyelid retractor aponeurosis becomes lax and its function weakens. As a result, the inferior border of the tarsus moves forward and upward, and the eyelid margin shifts downward.
Relaxation and displacement of the orbicularis oculi muscle: The orbicularis oculi muscle relaxes and lifts away from the tarsus, and the direction of the muscle’s action changes, causing entropion.
Together, these two mechanisms cause typical involutional entropion, in which the entire lower eyelid turns inward toward the globe. From a pathological standpoint, simple excision of the skin and orbicularis muscle (Hotz procedure) is not a definitive correction; shortening and fixation of the supporting tissues themselves are necessary.
Optimizing the timing of surgery for congenital trichiasis: A comparative study of the nylon suture buried method and the Hotz procedure for congenital trichiasis confirmed that both procedures are effective, and the choice should be made according to the characteristics of each case6).
Long-term results of the lateral tarsal strip method: The LTS method is widely used for both age-related entropion and ectropion, and several studies have shown high effectiveness in long-term follow-up4, 5). Reports suggest that combining it with shortening of the retractor aponeurosis is effective in reducing recurrence5).
Treatment of cicatricial entropion (after trachoma): WHO-recommended procedures for post-trachoma eyelid entropion, such as bilamellar tarsal rotation surgery, have shown effectiveness, and standardization is progressing in endemic regions.
Improved minimally invasive buried-suture techniques: New suture methods that can be performed in the outpatient setting (improved buried-suture methods) are being studied, and the challenge is to achieve both lower recurrence and minimal invasiveness.
