Trichiasis

Trichiasis is a condition in which one or more eyelashes grow or turn inward toward the eyeball, causing the lashes to rub against the cornea or conjunctiva. It is typically the result of eyelid malposition or scarring rather than an extra row of lashes. The abnormal lash direction can irritate the ocular surface and may lead to tearing, a foreign body sensation, redness, and photophobia, with potential development of corneal surface disease if not addressed.

Causes include scarring of the eyelid from infections (notably trachoma), trauma, chemical burns, or inflammatory diseases such as ocular cicatricial pemphigoid; eyelid inflammation (blepharitis) and meibomian gland dysfunction; entropion (inward turn of the eyelid margin) or, less commonly, congenital eyelid abnormalities. Distinguishing trichiasis from distichiasis (an extra row of lashes) or simply entropion is important for management.

Diagnosis is primarily clinical, made by slit-lamp examination with eyelid eversion to identify lashes touching the cornea or conjunctiva and to assess corneal integrity. It is usually a bilateral finding and may recur after treatment.

Treatment aims to relieve irritation and prevent corneal damage. Offending lashes can be removed by epilation, electrolysis, laser hair removal, or cryotherapy, with some cases requiring repeated sessions. Treating underlying lid disease (lid hygiene for blepharitis, management of meibomian gland dysfunction) is important. In cases of significant lid malposition or recurrence, surgical options such as entropion repair, canthoplasty, or tarsorrhaphy may be necessary to reposition the eyelid and protect the cornea. Prognosis improves with appropriate treatment, though recurrence is possible, and chronic trichiasis can lead to progressive corneal scarring and vision loss if untreated.