Entropion is a common physical misalignment where the eyelid margin rotates inward. This uncomfortable condition causes the skin and lashes to rub against the delicate tissues of the eye. This malposition can range from a mild annoyance to a source of significant damage to the sensitive ocular surface. Understanding this structural issue is the first step toward finding relief.
Identifying the Condition
The medical term for this inward rotation of the eyelid margin is entropion, which most commonly affects the lower eyelid. The entire edge of the eyelid, including the skin and eyelashes, rolls toward the eyeball. This friction causes the lashes (trichiasis) to constantly scrape against the cornea and the conjunctiva. This mechanical irritation causes the persistent, gritty discomfort patients often describe as having sand in their eye. Entropion requires prompt attention to prevent long-term damage.
Understanding the Causes
The most frequent cause of entropion is involutional, meaning it is related to the natural process of aging. As people age, the supportive muscles and tendons within the eyelid weaken and stretch, leading to horizontal laxity of the lid. This change involves the separation of the lower eyelid retractors, the muscles that pull the eyelid down. Simultaneously, the preseptal orbicularis oculi muscle may override its normal position, causing the eyelid to flip inward.
The second major category is cicatricial entropion, which arises from scar tissue formation on the inner surface of the eyelid. This scarring can result from previous trauma, chemical burns, or chronic inflammatory conditions such as trachoma. The contracture of this scar tissue physically shortens the posterior layer of the eyelid, forcing the margin to turn toward the globe. A less common form is congenital entropion, which is present at birth due to developmental anomalies.
Immediate Effects on Vision and Comfort
The constant abrasive contact between the eyelashes and the eye’s surface generates uncomfortable symptoms. Patients frequently report a persistent foreign body sensation and pain, alongside sensitivity to light (photophobia). The irritation triggers excessive tearing (epiphora) as the eye attempts to flush out the irritant. This continuous rubbing also leads to redness (conjunctival injection) and often a discharge or crusting along the eyelid margin.
The most serious consequence is the potential for long-term mechanical damage to the cornea, the transparent dome covering the iris and pupil. The friction from the misdirected lashes can cause small scratches, or corneal abrasions, which leave the eye vulnerable to infection. If left untreated, these abrasions can progress to corneal ulcers, which are open sores that significantly threaten vision. Permanent scarring from chronic irritation or repeated ulceration can lead to irreversible visual impairment.
Treatment and Management Options
Several non-surgical measures can be employed for temporary relief while a definitive treatment plan is arranged. Applying medical tape to the cheek can physically pull the lower eyelid downward, temporarily rotating the margin back into a normal position. Artificial tears and lubricating ointments help reduce friction and soothe the irritated surface. In some cases, a soft bandage contact lens may be fitted as a protective shield over the cornea.
For spastic entropion, which involves temporary muscle tightening, botulinum toxin injections can temporarily relax the orbicularis muscle, reducing the inward pull. The only permanent correction for entropion is surgery, which is highly effective and typically performed as an outpatient procedure.
Surgical Techniques
The specific surgical technique depends on the underlying cause. For age-related involutional entropion, the procedure often involves tightening the stretched lower eyelid retractors and correcting the horizontal laxity of the lid. In cases of cicatricial entropion, the surgery focuses on releasing the scar tissue and lengthening the posterior layer of the eyelid, often requiring a graft to reposition the eyelid margin correctly.