Anthony Loizides
Foundation Doctor, Royal Sussex County Hospital
Introduction
Entropion is an inward turning of the eyelid margin, most often affecting the lower lid. It is one of the more common eyelid malpositions encountered in ophthalmology and oculoplastics clinics, yet it is easy for junior doctors to overlook, since patients often present with vague symptoms such as a gritty or watery eye rather than an obviously abnormal-looking lid. Recognising entropion matters because, left untreated, it can progress to genuine corneal damage (1).
Why It Happens: The Four Types
Entropion is generally classified into four types, each with a different underlying mechanism (1).
Involutional entropion is by far the most common type, typically affecting the lower lid in older patients. It results from age-related laxity of the eyelid tissues, including horizontal laxity of the tarsus and canthal tendons, weakening of the lower eyelid retractors, and the pretarsal orbicularis muscle riding up over the preseptal orbicularis. Prevalence has been reported at around 2% in people over 60 (2).
Cicatricial entropion is caused by scarring and shortening of the posterior lamella, the inner layer of the eyelid. This can result from chronic inflammatory or autoimmune conditions, infection, burns, or trauma, and tends to affect the upper lid more often than involutional entropion does (1).
Spastic entropion develops from involuntary spasm of the orbicularis muscle, usually triggered by ocular irritation or inflammation. It often occurs in patients who already have some degree of underlying involutional change, and can be seen after intraocular surgery (1).
Congenital entropion is rare, resulting from developmental abnormalities of the lower eyelid retractors or tarsal plate. It is present from birth and distinct from epiblepharon, a more common condition in children where an extra fold of skin pushes the lashes inward without the eyelid margin itself being mispositioned (1).
Why It Matters Clinically
Once the eyelid margin turns inward, the eyelashes rub against the ocular surface with every blink. This constant mechanical irritation can cause corneal abrasion, punctate epithelial erosions, and, if it continues untreated, progress to corneal scarring, thinning, and neovascularisation. In severe or longstanding cases, this can result in a corneal ulcer or, rarely, perforation. This is why entropion, despite often looking like a minor cosmetic issue, is worth taking seriously as a junior doctor (1).
How Patients Present
Typical symptoms include a foreign body sensation, redness, watering, and general ocular irritation. Patients may also report photophobia, blurred vision, or a burning sensation. On examination, the eyelid margin and lashes may be visibly rotated inward, though in early or intermittent cases, particularly involutional entropion, the malposition may only become obvious when the patient is asked to blink firmly or when the lid is examined on downgaze. A useful bedside sign is the eyelid laxity or ‘snap-back’ test, where the lower lid is pulled away from the globe and observed for how quickly it returns to its normal position, a sluggish return suggesting significant horizontal laxity (3).
Entropion should be distinguished from trichiasis, where the lashes point posteriorly without the eyelid margin itself being inverted, and from distichiasis, an anomalous extra row of lashes (3).
How It Is Managed
Conservative measures are often used for symptom relief or while awaiting definitive treatment. These include ocular lubricants, taping the lower lid down to prevent inward rotation, and botulinum toxin injection into the orbicularis muscle, which can be particularly useful in spastic entropion, although its effect is temporary and injections typically need repeating every few months (3).
Surgical correction is usually required for lasting resolution, and the choice of procedure depends on the underlying mechanism.
Quickert (everting) sutures are a fast, minimally invasive option that can be used as a temporising measure or for spastic entropion, but they carry a relatively high recurrence rate when used alone (4).
The lateral tarsal strip procedure addresses horizontal eyelid laxity directly and is one of the most commonly performed operations for involutional entropion, often combined with everting sutures or retractor reinsertion to reduce recurrence (3).
Lower eyelid retractor reinsertion targets the disinserted retractors specifically, and cicatricial entropion typically requires more complex reconstruction, sometimes involving a tarsal or mucous membrane graft to lengthen the shortened posterior lamella (1).
Tarsal rotation procedures, such as bilamellar tarsal rotation, are used specifically for upper lid cicatricial entropion, most notably trachomatous entropion, and are the technique recommended by the World Health Organization for this indication. The tarsal plate is incised and the distal portion rotated outward to redirect the lash line away from the globe. A more recent variant, posterior lamellar tarsal rotation, has shown superior long-term outcomes with lower recurrence compared with the original bilamellar technique in randomised trial data (5).
Conclusion
Entropion is a common but often under-recognised eyelid malposition, and understanding its four subtypes helps make sense of why the same-looking problem can have quite different underlying causes and treatments. For junior doctors, the key takeaway is straightforward: any patient presenting with a persistently irritated, watery eye and normal-looking conjunctiva is worth a closer look at the eyelid margin itself, since an entropion left unaddressed can progress from a simple irritation to genuine corneal damage.
References
1. EyeWiki. Entropion. American Academy of Ophthalmology.
2. Bergstrom R, Czyz CN. Entropion. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023.
3. Lo C, Glavas I. Diagnosis and Management of Involutional Entropion. EyeNet Magazine, American Academy of Ophthalmology. February 2016.
4. EyeWiki. Quickert Procedure. American Academy of Ophthalmology.
5. Habtamu E, Wondie T, Tadesse Z, et al. Posterior lamellar versus bilamellar tarsal rotation surgery for trachomatous trichiasis: long-term outcomes from a randomised controlled trial. EClinicalMedicine. 2019;16:73-80.