Merck Manual

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Richard C. Allen

, MD, PhD, University of Texas at Austin Dell Medical School

Reviewed/Revised Feb 2024
Topic Resources

Trichiasis is an anatomic misalignment of eyelashes, which rub against the globe, in a patient with no entropion.

Trichiasis is most often idiopathic, but known causes include blepharitis Blepharitis Blepharitis is inflammation of the eyelid margins that may be acute or chronic. Symptoms and signs include itching and burning of the eyelid margins with redness and edema. Diagnosis is by history... read more Blepharitis , posttraumatic and postsurgical changes, conjunctival scarring (eg, secondary to ocular mucous membrane pemphigoid Ocular Mucous Membrane Pemphigoid Ocular mucous membrane pemphigoid is a chronic, bilateral, progressive scarring and shrinkage of the conjunctiva with opacification of the cornea. Early symptoms are hyperemia and irritation... read more Ocular Mucous Membrane Pemphigoid , atopic keratoconjunctivitis Allergic Conjunctivitis Allergic conjunctivitis is an acute, intermittent, or chronic conjunctival inflammation usually caused by airborne allergens. Symptoms include itching, lacrimation, discharge, and conjunctival... read more Allergic Conjunctivitis , Stevens-Johnson syndrome Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) Stevens-Johnson syndrome and toxic epidermal necrolysis are severe cutaneous hypersensitivity reactions. Drugs, especially sulfa drugs, antiseizure drugs, and antibiotics, are the most common... read more Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) , or chemical injury Chemical burns Ocular burns can occur after thermal or chemical injuries and can result in serious complications, including permanent blindness. (See also Overview of Eye Trauma.) The blink reflex usually... read more Chemical burns ), epiblepharon (an extra lower eyelid skinfold that directs lashes into a vertical position), and distichiasis (a congenital extra row of eyelashes).

Diagnosis is usually clinical. Trichiasis differs from entropion Entropion and Ectropion Entropion is inversion of an eyelid. Ectropion is eversion of the lower eyelid. This photo shows entropion, inversion of the eyelid that most commonly affects the lower eyelids of older adults... read more Entropion and Ectropion in that the eyelid position is normal. Evaluation includes fluorescein staining to exclude corneal abrasion or ulceration.

Treatment is eyelash removal with forceps. If eyelashes grow back, which is a frequent occurrence, electrolysis or cryosurgery is more effective at permanently preventing recurrence. If entropion is present, treatment of the entropion should be performed.

Drugs Mentioned In This Article

Drug Name Select Trade
AK-Fluor, Bio Glo, Fluorescite, Fluorets , Fluor-I-Strip, Fluor-I-Strip A.T., Ful-Glo, Ophthalmicflur
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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