The unusual sensation of eyelashes growing inward, particularly toward the nasal side of the eye, points toward a common medical condition involving the eyelids. While eyelashes are normally angled outward to protect the eye, this misdirection causes them to scrape against the delicate surface of the eyeball. This inward growth is a symptom of an underlying anatomical change that requires medical evaluation to prevent damage to the eye’s surface.
Defining Misdirected Eyelash Growth
The general medical term for misdirected eyelashes that rub against the eye is trichiasis. This condition occurs when the hair follicle changes direction, causing one or more lashes to grow inward toward the cornea and conjunctiva, even though the overall eyelid position remains normal. Trichiasis is a common abnormality observed by an eye care professional.
It is important to distinguish trichiasis from entropion, where the entire eyelid margin rolls inward. Entropion causes the full set of lashes to contact the eye because the eyelid’s structure is compromised, typically affecting the lower lid in older adults. In contrast, trichiasis involves only the misalignment of individual lashes, often occurring in a localized area, such as the nasal side (medial canthal trichiasis).
Primary Causes of Inward Eyelash Misalignment
The core mechanism behind trichiasis is usually a disruption and scarring of the eyelid margin, which pulls the hair follicle out of its normal outward orientation. Chronic inflammation is the most frequent cause of this damage, often caused by severe blepharitis (inflammation of the eyelid edges). This persistent swelling and irritation damages the base of the lash, altering its growth trajectory.
As the inflammation subsides and the tissue heals, scar tissue forms along the eyelid margin. This contracting scar tissue physically distorts the lash line and tugs the hair follicles inward. Traumatic injuries, such as chemical burns or mechanical damage to the eyelid, can also lead to scarring and subsequent misdirection of lashes during healing.
Infectious diseases like trachoma, caused by the bacterium Chlamydia trachomatis, are a significant cause of widespread scarring and trichiasis globally. Rare inflammatory conditions, such as ocular cicatricial pemphigoid, can also cause severe eyelid scarring that leads to extensive lash misdirection. Additionally, the natural aging process can contribute to mild forms of trichiasis, particularly near the nasal corner, as the tissues and muscle support in the eyelid margin lose stability.
Symptoms and Potential Ocular Damage
The primary symptoms result directly from the mechanical friction against the eye’s surface. Patients commonly report a foreign body sensation, feeling as if a grain of sand is constantly in the eye, caused by the stiff lash hair scraping the cornea and conjunctiva. This continuous rubbing leads to redness, excessive tearing (epiphora), and sensitivity to light (photophobia).
If left unaddressed, the constant irritation can result in more serious complications affecting the cornea. The abrasion from the lashes can cause small breaks in the corneal surface, known as superficial punctate keratopathy or corneal abrasions. In severe cases, this damage can progress to corneal ulceration and scarring, particularly if the central visual axis is affected. Scarring on the cornea can significantly reduce visual clarity and potentially lead to permanent vision impairment.
Treatment Options for Permanent Correction
Management is determined by the number of lashes involved and the severity of the damage. For a single or small number of lashes, the initial step is often mechanical epilation, which involves plucking the offending lashes with forceps. This provides immediate relief, but the lash will regrow in the same direction within a few weeks to months, making this only a temporary solution.
For a permanent solution, the hair follicle must be destroyed to prevent regrowth. One method is electrolysis, which uses a fine needle to deliver an electrical current and heat to coagulate the hair root. This is done under local anesthesia and must be performed on each individual follicle, often requiring multiple sessions due to a reported recurrence rate of up to 50%.
Other definitive interventions include radiofrequency ablation and cryotherapy, which uses extreme cold to destroy the errant follicles. Cryotherapy is often reserved for cases involving a larger segment of the eyelid margin, although it carries a risk of collateral damage, such as pigment changes and scarring to adjacent tissue. In cases of extensive scarring or eyelid malposition, a minor surgical procedure, such as excising the affected segment or repositioning the eyelid margin, may be necessary to restore the normal anatomy and prevent recurrence.