Eye Diseases > Eyelids

Trichiasis

Evidence-based assessment and management of misdirected eyelashes. Comprehensive guide covering etiology, pathogenesis, classification, diagnosis, and treatment protocols for optometry practice.

Trichiasis: Eyelashes growing inward toward the cornea (shown in red)

Trichiasis is a condition characterized by the misdirection of eyelashes toward the ocular surface, causing them to rub against the cornea and conjunctiva. This aberrant lash growth can lead to significant ocular discomfort, corneal damage, and potential vision-threatening complications if left untreated.

Primary Causes

Chronic blepharitis: Posterior blepharitis with meibomian gland dysfunction
Cicatricial conditions: Scarring of the eyelid margin
Trachoma: Chlamydia trachomatis infection (leading cause globally)
Ocular pemphigoid: Autoimmune cicatrizing conjunctivitis
Stevens-Johnson syndrome/Toxic epidermal necrolysis (SJS/TEN): Severe mucocutaneous reactions
Chemical or thermal burns: Eyelid scarring from injury
Herpes zoster ophthalmicus: Post-herpetic lid scarring
Trauma: Mechanical injury to the eyelid margin
Post-surgical: Following eyelid surgery or repair
Idiopathic: No identifiable underlying cause

Mechanism of Development

Inflammation and scarring: Chronic inflammation of the eyelid margin leads to fibrosis and contraction of the tarsal conjunctiva
Posterior lamella shortening: Scarring causes the posterior lamella to contract, rotating the lash line posteriorly
Follicular misdirection: Damage to the lash follicles alters the normal growth direction of individual lashes
Loss of lash barrier: Destruction of the normal anatomical barriers allows lashes to grow in aberrant directions
Metaplasia: In severe cases, conjunctival metaplasia may contribute to abnormal lash growth patterns

Corneal Impact

Misdirected lashes cause mechanical trauma to the corneal epithelium with each blink, leading to:

Punctate epithelial erosions
Recurrent corneal abrasions
Corneal scarring and neovascularization
Secondary bacterial infections
Potential corneal perforation in severe, untreated cases

By Extent

Minor/Focal trichiasis: Few isolated lashes (1-5 lashes) touching the cornea
Segmental trichiasis: A segment of the eyelid affected (typically one-third or less)
Diffuse/Major trichiasis: Extensive involvement affecting most or all of the eyelid

By Eyelid Involved

Upper lid trichiasis
Lower lid trichiasis
Both lids (more common in severe cicatricial disease)

By Associated Lid Position

Trichiasis with normal lid position: Lid margin properly positioned, only lashes misdirected
Trichiasis with entropion: Both lid margin and lashes turned inward
Pseudotrichiasis: Normal lashes touching cornea due to lid malposition (entropion) rather than true lash misdirection

Age: Increased prevalence in elderly due to chronic blepharitis
Geographic location: Higher in trachoma-endemic areas (sub-Saharan Africa, parts of Asia)
Poor hygiene: Increases risk of trachoma and chronic lid infections
Autoimmune conditions: Ocular pemphigoid, Stevens-Johnson syndrome
History of ocular herpes zoster: Post-inflammatory scarring
Chemical exposure: Occupational or accidental chemical injuries
Previous eyelid surgery: Scarring from procedures
Chronic eye rubbing: Can contribute to lid margin changes
Radiation therapy: To the periocular region
Chronic use of topical medications: Particularly glaucoma medications causing cicatrization

Eyelid Signs

One or more lashes directed posteriorly toward the globe
Lashes touching the cornea or conjunctiva on examination
Lid margin scarring or irregular contour
Loss of normal lash architecture
Signs of chronic blepharitis (crusting, erythema, telangiectasia)
Meibomian gland dysfunction or dropout
Poliosis (whitening) of affected lashes in some cases
Associated entropion or ectropion in some cases

Ocular Surface Signs

Corneal signs:
- Punctate epithelial erosions (fluorescein staining)
- Linear corneal abrasions corresponding to lash contact
- Corneal infiltrates or ulceration (if infected)
- Superficial corneal scarring and irregularity
- Corneal neovascularization (chronic cases)
- Pannus formation (trachomatous trichiasis)
Conjunctival signs:
- Conjunctival injection
- Papillary reaction
- Conjunctival scarring or symblepharon (cicatricial cases)
- Subconjunctival fibrosis
Excessive tearing (reflex epiphora)
Mucoid discharge

Foreign body sensation: Most common complaint, persistent scratching feeling
Eye pain: Sharp or aching pain, worsens with blinking
Photophobia: Light sensitivity due to corneal irritation
Tearing: Reflex lacrimation from corneal irritation
Redness: Ocular injection and discomfort
Blurred vision: From tear film irregularity, corneal surface disruption, or scarring
Mucoid discharge: Especially upon waking
Blepharospasm: Involuntary lid closure in severe cases
Recurrent eye infections: Due to compromised corneal barrier

Note: Symptoms typically worsen throughout the day with continued blinking and may improve temporarily after manual lash removal.

Ocular Complications

Recurrent corneal erosions: Chronic epithelial breakdown
Corneal scarring: Leading to irregular astigmatism and decreased vision
Corneal neovascularization: Blood vessel ingrowth into cornea
Persistent corneal epithelial defects: Non-healing epithelial breakdown
Bacterial keratitis: Secondary infection of compromised cornea
Corneal ulceration: Potentially vision-threatening stromal involvement
Corneal perforation: Rare but severe complication requiring urgent surgery
Astigmatism: Irregular corneal surface causing refractive error
Amblyopia: In children with chronic visual axis obstruction
Dry eye disease: From conjunctival scarring and goblet cell loss

Long-term Sequelae

Permanent vision loss from corneal scarring
Chronic pain and discomfort
Decreased quality of life
Need for multiple interventions
Psychological impact from chronic eye condition

Associated Systemic Conditions

Trachoma: Associated with poverty, lack of access to clean water and sanitation
Ocular cicatricial pemphigoid: May have oral, nasal, pharyngeal, esophageal involvement
Stevens-Johnson syndrome/TEN:
- Severe systemic illness with high mortality
- Multi-organ involvement
- Often drug-induced
Herpes zoster: Systemic viral infection, risk of postherpetic neuralgia
Rosacea: Skin manifestations, may have cardiovascular associations
Atopic dermatitis: Systemic allergic/inflammatory condition

Systemic Workup Indications

Consider systemic evaluation for:

Bilateral progressive trichiasis without obvious local cause
Signs of mucous membrane pemphigoid (oral lesions, skin blistering)
History of severe drug reaction
Unexplained systemic symptoms
Need for immunosuppressive therapy consideration

Clinical History

Duration and progression of symptoms
Previous episodes or treatments
History of eye infections, trauma, surgery
Systemic conditions (autoimmune, skin disorders)
Medications (especially topical eye drops)
Geographic history (trachoma endemic areas)
Occupational exposures

Clinical Examination

1. External Examination:

Observe lid position and symmetry
Assess lash direction and density
Evaluate for lid margin abnormalities
Check for signs of chronic blepharitis
Look for skin lesions or scarring

2. Slit Lamp Biomicroscopy:

Eyelids: High magnification of lid margin, document number and location of aberrant lashes, assess meibomian gland structure
Conjunctiva: Check for injection, scarring, symblepharon, evert lids to assess tarsal conjunctiva
Cornea: Fluorescein staining to identify epithelial defects, document location and extent
Tear film: Assess quality and quantity (TBUT, Schirmer’s test if indicated)

3. Supplementary Tests & Imaging Findings:

Fluorescein Staining Pattern (slit lamp, blue filter):

Inferior/interpalpebral PEE: Most common pattern; corresponds to lower lid lash-contact zone
Linear corneal abrasions: Horizontal tracks reflecting individual lash trajectory — highly characteristic of trichiasis
Superior or circumferential staining: Suggests upper lid trichiasis or cicatricial disease — warrants urgent assessment
Oxford Grading for documentation: Grade I (<⅓ cornea), Grade II (⅓–⅔), Grade III (>⅔) — record at each visit to monitor progression or improvement

Anterior Segment OCT (AS-OCT) — indicated in cicatricial or complex cases:

Corneal epithelial thinning or irregularity at lash-contact zones
Hyperreflective posterior lamella thickening indicating tarsal fibrosis
Symblepharon extent mapping and fornix depth assessment in cicatricial disease
Lash follicle position relative to mucocutaneous junction (informs surgical planning)

Corneal Topography — when irregular astigmatism is suspected:

Elevated Surface Regularity Index (SRI) and Surface Asymmetry Index (SAI) from chronic surface disruption
Inferior corneal irregularity or localised flattening at lash-contact zones
Useful for quantifying optical impact and monitoring corneal recovery after treatment

Meibography (infrared):

Meibomian gland dropout and distortion in blepharitis-associated trichiasis
Guides severity grading and management of underlying MGD contributing to lid margin disease

Other:

Photography: Document lash number, position, and corneal staining pattern at each visit
Conjunctival swab/culture: If secondary bacterial keratitis or infected epithelial defect is present

Grading Scales

Clinical Severity Grade (General)

Grade	Lash Count	Corneal Involvement	Symptoms	Suggested Action
Grade 1 — Mild	1–3 isolated lashes	PEE only, <⅓ cornea (Oxford Grade I)	Mild FBS, occasional irritation	Epilation + lubricants; monitor
Grade 2 — Moderate	4–10 lashes or segmental	PEE >⅓ cornea or linear abrasions (Oxford Grade II)	Frequent FBS, photophobia, tearing	Epilation + referral for definitive ablative treatment
Grade 3 — Severe	>10 lashes or diffuse	Scarring, ulceration, or neovascularization (Oxford Grade III)	Significant pain, blurred vision, blepharospasm	Urgent ophthalmology referral; surgical correction

WHO FISTO Trachoma Grading (for trachoma-endemic contexts)

The WHO simplified trachoma grading uses five signs (FISTO). Trichiasis (TT) and corneal opacity (CO) represent end-stage disease and drive surgical decision-making:

WHO Sign	Definition	Clinical Action
TF — Follicular Inflammation	≥5 follicles on upper tarsal conjunctiva	Antibiotic treatment (azithromycin)
TI — Intense Inflammation	Pronounced tarsal inflammation obscuring >50% of deep tarsal vessels	Antibiotic treatment; high community transmission risk
TS — Trachomatous Scarring	White lines or bands on upper tarsal conjunctiva	Monitor; evidence of prior infection and fibrosis
TT — Trachomatous Trichiasis	≥1 eyelash rubbing the eyeball, or evidence of recent epilation	Surgical intervention required
CO — Corneal Opacity	Corneal opacity obscuring any part of the pupil margin	Vision loss established; consider visual rehabilitation

Singapore context: Trachoma has been eliminated in Singapore (WHO-certified). FISTO grading is most relevant when assessing patients with a history of living in or travelling from trachoma-endemic regions (parts of sub-Saharan Africa, South Asia, Middle East). In Singapore practice, the vast majority of trichiasis is blepharitis-related or cicatricial in origin.

Singapore Optometry Scope Note: Optometrists can perform mechanical epilation for mild trichiasis and provide supportive care (ocular lubrication). Prescription of topical antibiotics for corneal defects requires referral to ophthalmology or a medical practitioner. Moderate to severe cases, recurrent trichiasis, or cases requiring definitive surgical intervention should be referred to ophthalmology.

Conservative Management

1. Mechanical Epilation (First-line for Mild Cases)

Procedure: Use sterile fine forceps, grasp lash at base and pull in direction of growth
Advantages: Simple, immediate relief, no anesthesia needed
Disadvantages: Temporary (lash regrows in 4-6 weeks), often thicker and more irritating
Frequency: May need repeated every 3-6 weeks
Patient education: Can teach careful self-epilation for recurrent cases

2. Medical Management (Adjunctive)

Lubricating drops: Frequent preservative-free artificial tears for corneal protection
Lubricating ointment: At bedtime to protect cornea overnight
Topical antibiotics: If epithelial defects present (Chloramphenicol 0.5% or fusidic acid gel 1%)
Treat underlying blepharitis: Lid hygiene, topical azithromycin or erythromycin ointment

Definitive Treatments (Ophthalmology Referral Required)

1. Electrolysis

Indication: Few isolated lashes (1-5)
Procedure: Electrical current destroys lash follicle
Success rate: 50-90% depending on technique

2. Cryotherapy

Indication: Segmental trichiasis (5-10 lashes)
Protocol: Double freeze-thaw cycle (-20°C for 20-30 seconds)
Success rate: 60-80% for segmental disease
Note: May cause lid depigmentation (problematic in darker skin)

3. Laser Ablation

Types: Argon laser, diode laser, radiofrequency
Advantages: Precise, less collateral damage than cryotherapy
Success rate: 70-85%

4. Surgical Procedures

Posterior lamella repositioning (for cicatricial entropion)
Anterior lamellar repositioning with lash follicle excision
Eyelid margin split with cryotherapy (diffuse upper lid trichiasis)
Mucous membrane grafting (severe cicatricial disease)
Tarsotomy procedures (segmental disease)

Treatment Selection Guide

Number of Lashes	Recommended Treatment
1–3 isolated lashes	Epilation ± electrolysis or laser
4–10 lashes (segmental)	Cryotherapy or laser ablation
>10 lashes (diffuse)	Surgical correction (posterior lamella repositioning, lid margin split)
Trichiasis + entropion	Surgical entropion repair with follicle destruction
Severe cicatricial disease	Complex lid reconstruction ± mucous membrane grafting

Refer to Ophthalmology for:

Urgent referral:

Corneal ulceration or infiltrate
Severe corneal scarring affecting vision
Signs of corneal perforation
Progressive disease despite conservative management

Routine referral:

Moderate to severe trichiasis (>5 lashes)
Recurrent trichiasis after repeated epilation
Patient request for definitive treatment
Associated entropion or lid malposition
Suspected underlying cicatricial condition

Visual Prognosis

Excellent: If treated early before significant corneal scarring
Good: For mild cases with timely intervention
Guarded: In cases with established corneal scarring or neovascularization
Poor: Advanced cases with severe corneal damage, especially if neglected

Treatment Success Rates

Epilation: 100% immediate relief, but 100% recurrence in 4-6 weeks
Electrolysis: 50-90% long-term success
Cryotherapy: 60-80% success
Laser ablation: 70-85% success rate
Surgical correction: 80-95% success for appropriate cases

Factors Affecting Prognosis

Favorable factors:

Early detection and treatment
Few lashes involved
No active cicatrizing disease
Good patient compliance

Poor prognostic factors:

Extensive involvement
Active cicatricial disease
Previous failed treatments
Severe dry eye disease

It is important to distinguish trichiasis from other conditions that may present with similar symptoms or clinical findings:

1. Distichiasis

Definition: Additional row of lashes growing from meibomian gland orifices
Key difference: True second row of lashes vs. misdirected single row
Etiology: Congenital or acquired (metaplasia of meibomian glands)

2. Pseudotrichiasis (Entropion)

Definition: Inward rotation of entire eyelid margin
Key difference: Entire lid margin turned in vs. only lashes misdirected
Management: Lid surgery required, not lash treatment

3. Aberrant Lashes

Definition: One or few congenitally misdirected lashes
Key difference: Congenital vs. acquired, no underlying lid pathology

Diagnostic Comparison Table

Condition	Lash Position	Lid Margin	Typical Cause
Trichiasis	Misdirected posteriorly	Normal position	Inflammation, scarring
Distichiasis	Extra row of lashes	Normal position	Congenital, metaplasia
Entropion	Normal to lid	Rotated inward	Lid laxity, scarring
Aberrant Lash	Single misdirected	Normal position	Congenital anomaly

Always evert the upper lid. Superior trichiasis from upper lid lashes is easily missed. Evert both lids at every relevant visit and instil fluorescein — a superior arc of corneal staining (rather than the typical inferior pattern) is the key clue to upper lid trichiasis and is often the only finding.

Fine or non-pigmented lashes are easy to miss. In elderly patients, post-chemotherapy patients, or those with lash colour changes, aberrant lashes can be transparent and nearly invisible at routine magnification. Examine the lid margin under high magnification with a narrow oblique slit beam, and use retroillumination when in doubt.

Counsel patients before epilation — regrowth is expected, not failure. Lashes regrow in 4–6 weeks after epilation and often return thicker and more irritating. Frame epilation as temporary bridge management, not definitive treatment. Set expectations clearly and schedule follow-up or arrange referral for definitive care at the same visit.

Distinguish true trichiasis from pseudotrichiasis before epilating. If the problem is lid malposition (entropion), epilating lashes addresses the symptom but not the cause, and repeated trauma to a normally-positioned lash follicle in a misdirected lid may worsen lid architecture over time. Always assess lid margin position before any lash removal — if the entire lid margin is rotated inward, the diagnosis is entropion, not trichiasis.

In East Asian paediatric patients, think epiblepheron first. Children presenting with foreign body sensation and lash-corneal touch are far more likely to have epiblepharon (inward folding of pretarsal skin pushing lashes against the cornea, with a normally-positioned lid margin) than true trichiasis. Most mild epiblepharon resolves spontaneously by age 5–6 years as the mid-face develops. True acquired trichiasis in children requires a specific underlying cause.

Cicatricial trichiasis is progressive — do not manage with epilation alone. In ocular cicatricial pemphigoid (OCP), SJS/TEN, and severe herpes zoster ophthalmicus, the underlying scarring process continues despite local treatment. Repeated epilation becomes progressively less effective. These patients need early ophthalmology involvement, systemic immunosuppression evaluation (for active OCP), and timely definitive surgical correction before cumulative corneal damage becomes irreversible.

Singapore Optometry Scope Note — Document epilation systematically. When performing epilation in clinic, record: (1) number of lashes removed, (2) anatomical location (upper/lower lid; distance from medial canthus in mm or by lid thirds), (3) Oxford corneal fluorescein grade before and after, and (4) planned review interval. Consistent documentation across visits strengthens the referral letter and allows objective tracking of disease progression toward the threshold for definitive treatment.

Rajak SN, Collin JRO. Trichiasis. In: Yanoff M, Duker JS, eds. Ophthalmology. 5th ed. Elsevier; 2019:1418-1421.
Burton MJ, Ramke J, Marques AP, et al. The Lancet Global Health Commission on Global Eye Health: vision beyond 2020. Lancet Glob Health. 2021;9(4):e489-e551.
Hu VH, Massae P, Weiss HA, et al. Bacterial infection in scarring trachoma.Invest Ophthalmol Vis Sci. 2011;52(5):2181-2186.
Chi MJ, Baek SH. Clinical analysis of entropion and trichiasis in South Korea: a nationwide population-based study. Cornea. 2012;31(10):1115-1118.
Reacher M, Foster A, Huber J. Trichiasis surgery for trachoma. The bilamellar tarsal rotation procedure. World Health Organization. 1993.
Sullivan JH, Beard C, Bullock JD. Cryotherapy for treatment of trichiasis.Am J Ophthalmol. 1976;82(1):117-121.
Wood JR, Anderson RL. Complications of cryosurgery. Arch Ophthalmol. 1981;99(8):1395-1398.
Olver JM. Surgery for cicatricial ectropion and trichiasis. Int Ophthalmol Clin. 2002;42(2):87-99.
McCracken MS, Kikkawa DO, Vasani SN. Treatment of trichiasis and distichiasis by eyelash trephination.Ophthalmic Plast Reconstr Surg. 2006;22(5):349-351.
Hatt S, Wormald R, Burr J. Treatment of trichiasis by surgery.Cochrane Database Syst Rev. 2006;(3):CD004008.
Adamu Y, Alemayehu W. A randomized clinical trial of the success rates of bilamellar tarsal rotation and tarsal advance and rotation for upper eyelid trachomatous trichiasis.Br J Ophthalmol. 2004;88(12):1536-1539.
Rajak SN, Habtamu E, Weiss HA, et al. The clinical phenotype of trachomatous trichiasis in Ethiopia: not all trichiasis is due to entropion. Invest Ophthalmol Vis Sci. 2011;52(10):7974-7980.
Foster A, Sommer A. Corneal ulceration, measles, and childhood blindness in Tanzania.Br J Ophthalmol. 1987;71(5):331-343.
Sotozono C, Ang LP, Koizumi N, et al. New grading system for the evaluation of chronic ocular manifestations in patients with Stevens-Johnson syndrome. Ophthalmology. 2007;114(7):1294-1302.
Elder MJ, Bernauer W. Monitoring for cicatrising conjunctivitis associated with systemic disease.Eye (Lond). 1997;11(Pt 2):157-158.

Clinical Illustration

Overview

Etiology