Entropion is an ocular condition defined by the inward turning of the eyelid margin, causing the eyelashes and skin to constantly rub against the surface of the eye. This mechanical friction irritates the delicate tissues, particularly the cornea. It most frequently affects the lower eyelid and is often associated with aging. Professional attention is necessary to prevent lasting damage to the eye.
Recognizing the Signs and Symptoms
The inward rotation of the lashes against the eyeball creates a persistent sensation similar to having a foreign body in the eye. This abrasive contact is the direct source of most symptoms. The eye attempts to flush out this irritation by producing an excessive amount of tears, known as epiphora.
Chronic friction causes the conjunctiva and the eye to become noticeably red and inflamed. Many people also report a heightened sensitivity to bright light (photophobia) and to wind. Due to the irritation, a thick mucous discharge and crusting along the eyelid margin may also develop.
The Underlying Causes of Entropion
Entropion is classified into distinct categories based on its cause, the most common being involutional entropion. This type typically affects older adults due to age-related tissue degradation. It involves progressive horizontal laxity of the eyelid and the weakening or disinsertion of the lower eyelid retractor muscles. This weakening allows the strong preseptal orbicularis oculi muscle to override the structural supports and rotate the margin inward.
Cicatricial entropion arises from scarring of the inner eyelid surface, known as the conjunctiva. This scarring causes the tissue to contract vertically, pulling the eyelid margin inward toward the globe. Causes of this scarring include trauma, chemical burns, or certain inflammatory diseases and infections, such as trachoma.
The third form is spastic entropion, resulting from an acute spasm of the orbicularis oculi muscle. This contraction is typically triggered by temporary ocular irritation, inflammation, or sometimes following eye surgery. The irritation caused by the initial inward turning perpetuates the muscle spasm and further rotation of the eyelid.
Treatment and Correction Methods
Treatment is determined by the cause and severity, often beginning with temporary measures to protect the eye surface from the abrasive lashes. Non-surgical options include lubricating eye drops and ointments to provide a protective barrier over the cornea. In cases of acute irritation, a specialized soft contact lens (bandage lens) can be worn as a physical shield between the lashes and the eye.
Temporary manual correction methods can also reposition the eyelid. One technique involves placing transparent skin tape on the lower eyelid and pulling it gently down and outward toward the cheek to evert the margin. For spastic entropion, a temporary fix involves injecting botulinum toxin (Botox) into the orbicularis muscle to relax the spasm, with effects lasting up to six months.
Surgical intervention is the definitive correction for entropion, especially for age-related and scar-related cases. The goal is to restore the normal anatomical position of the eyelid by tightening loose structures and repositioning the margin. For involutional entropion, common procedures include the lateral tarsal strip procedure, which tightens the eyelid horizontally, and reinsertion of the lower eyelid retractors.
These procedures are usually performed in an outpatient setting using local anesthesia, allowing the patient to return home the same day. For cicatricial entropion, the surgeon may release scar tissue and occasionally use a mucosal graft to lengthen the inner lining of the eyelid. Full recovery generally occurs within a couple of weeks.
Long-Term Risks of Ignoring the Condition
Failing to address entropion allows the persistent friction from the inward-turned lashes to inflict progressive damage on the eye’s surface. The initial damage often manifests as a corneal abrasion, which is a superficial scratch on the outer layer of the eye. This abrasion weakens the surface integrity, making the eye susceptible to more serious complications.
As the rubbing continues, the abrasion can worsen and develop into a corneal ulcer, an open sore on the cornea. Corneal ulcers are serious because they create a pathway for bacteria and other pathogens, increasing the risk of severe eye infection. An untreated ulcer can lead to the formation of permanent opaque scar tissue on the cornea. This scarring directly obstructs the passage of light, resulting in a reduction or permanent loss of vision.