PanOph

Trachoma

Cornea

1. Basics & Epidemiology

Exam pearl
  • Clinical Analogy: Think of trachoma as a relentless house fire inside the eyelid. Each recurrent infection with Chlamydia trachomatis adds another layer of scarring to the tarsal conjunctiva - just as fire progressively chars wood deeper with each flare. The lid slowly buckles inward, the lashes scratch the cornea like sandpaper, and blindness results from repeated abrasion - all preventable if you extinguish the fire early enough.
  • Trachoma is the world's leading infectious cause of blindness and the leading cause of preventable blindness from infection. It is a disease of poverty, crowding, and poor hygiene - a socio-medical tragedy more than a purely ophthalmic one.
ParameterData
Global burden (active trachoma)• 92 million people at risk of trachoma blindness (March 2026 data) • ~1.9 million people with blindness or visual impairment (World Health Organization, September 2026)
Trachomatous trichiasis (TT)• ~1.2 million cases globally (20 March 2026)
Endemic countries• 29 countries • Primarily in Africa, with foci in Central and South America, Asia, Australia and the Middle East
India• World Health Organization validated India as having eliminated trachoma as a public health problem in 2024
Age group affected• Active disease: commonly affects preschool-aged children; infection becomes less frequent and shorter in duration with increasing age • Visual impairment: onset is typically between 30 and 40 years, but may occur earlier in highly endemic communities
Sex predilection• Women are blinded up to 4 times as often as men, probably because of closer contact with infected children and more frequent infection episodes
World Health Organization elimination target• Trachomatous inflammation - follicular (TF) <5% in children 1–9 yrs, sustained for at least 2 years in the absence of ongoing antibiotic mass drug administration (MDA), in each formerly endemic district • Trachomatous trichiasis (TT) unknown to the health system <0.2% in people ≥15 yrs • Health system able to identify and manage incident trachomatous trichiasis (TT)
Transmission• Direct contact (eye-to-eye, eye-to-nose secretions) • Fly vectors (Musca sorbens)
Risk factors• Inadequate hygiene • Crowded households • Inadequate access to water • Inadequate access to and use of sanitation • Active disease is common among preschool-aged children • Women are blinded up to 4 times as often as men

Viva Pearls

  • Trachoma is one of the World Health Organization neglected tropical diseases that can cause blindness; onchocerciasis can also cause blindness.
  • Musca sorbens (the “eye-seeking fly”) is a putative or likely mechanical vector of trachoma, particularly in some endemic settings.
  • Musca sorbens breeds preferentially in exposed human faeces; sanitation can reduce breeding sites.
  • Water, sanitation and hygiene interventions form part of environmental improvement and can reduce exposure to eye-seeking flies by improving sanitation and facial cleanliness.
  • Children are the principal reservoir of trachoma infection.
  • Adults may develop conjunctival scarring and blindness years later because of repeated or prolonged infection and cumulative damage.
  • Trachoma is not sexually transmitted in the context of ocular trachoma-associated strains; transmission occurs through infected ocular and nasal discharges and their direct or indirect transfer.
  • Unlike other Chlamydia trachomatis serovars, D–K are most commonly associated with urogenital infection, whereas L1–L3 cause lymphogranuloma venereum.
  • Trachoma is associated with Chlamydia trachomatis serovars A, B, Ba, and C.

2. Pathogen & Pathophysiology

Chlamydia trachomatis - Classification & Biology

Chlamydia trachomatis is an obligate intracellular gram-negative bacterium. It has a unique biphasic life cycle:

PhaseFormCharacteristics
ExtracellularElementary body (EB)• Infectious • Classically considered metabolically inactive, although it retains protein-translation capability • Enters host cells by endocytosis • Rigid outer membrane • The inclusion rapidly dissociates from the endolysosomal pathway
IntracellularReticulate body (RB)• Non-infectious • Metabolically active • Replicates within the chlamydial inclusion • Reorganizes into elementary bodies during the later developmental cycle
ReleaseElementary body (EB) release• Host-cell lysis or inclusion extrusion releases new elementary bodies (EBs) to infect adjacent cells • 48–72-hour developmental cycle
Serovar Specificity - EXAM CRITICAL
Serovar Specificity - EXAM CRITICAL
SerovarsDiseaseTissue tropism
A, B, Ba, C• Trachoma (ocular)• Conjunctival epithelium
D, E, F, G, H, I, J, K• Genital infections • Inclusion conjunctivitis • Neonatal ophthalmia• Genital epithelium • Conjunctival epithelium
L1, L2, L3• Lymphogranuloma venereum (LGV)• Draining regional lymph nodes
Notes
  • Ocular and genital serovars can infect both conjunctival and genital epithelium but show distinct organotropism; L1–L3 cause invasive lymphogranuloma venereum with dissemination to draining regional lymph nodes.
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Pathophysiology - The Scarring Cascade

Understanding the immunopathology is crucial for explaining why repeated infections cause progressive damage:

StepContent
Step 1 – Primary Infection• Chlamydia trachomatis elementary bodies attach to and enter conjunctival epithelial cells • Intracellular inclusion bodies form • Conjunctival pro-inflammatory cytokine responses, including interleukin-1 beta and tumour necrosis factor alpha, may occur • Interleukin-6 is also produced by stimulated conjunctival epithelial cells • Infection and inflammation can manifest as follicular trachomatous conjunctivitis (active trachoma).
Step 2 – Innate Immune Response• Neutrophils, macrophages, and dendritic cells are present in the inflammatory infiltrate of active trachoma • This inflammation is associated with conjunctival hyperemia or telangiectasia and follicular or papillary inflammation • Chlamydial components can activate innate immune signaling through Toll-like receptor 2- and Toll-like receptor 4-related pathways • Chlamydia trachomatis heat-shock protein 60 has been reported to signal through both Toll-like receptor 2 and Toll-like receptor 4 • Major outer membrane protein can signal through Toll-like receptor 2 • The precise heat-shock protein 60–Toll-like receptor 2/Toll-like receptor 4 mechanism in human trachoma remains incompletely established.
Step 3 – Adaptive Immune Response• A cluster of differentiation 4-positive T-helper 1-type response involving interferon-gamma is implicated in Chlamydia trachomatis clearance and is associated with active trachoma • Delayed-type hypersensitivity has been proposed as a mechanism of chlamydial immunopathology, but its role in human trachoma is not definitively established • Chronic conjunctival inflammation and dysregulated extracellular-matrix remodeling contribute to conjunctival scarring and fibrosis • Major outer membrane protein is a major immunologically important antigen, but it should not be described as the single key antigen.
Step 4 – Chronic Reinfection• Repeated episodes of trachomatous inflammation, often beginning in childhood and frequently associated with recurrent Chlamydia trachomatis exposure, can contribute to progressive conjunctival scarring • Progression may occur without detectable infection in established scarring • Each active infection episode should not be regarded as invariably adding fibrosis directly • Chlamydial persistence may involve viable, non-replicative or non-dividing, metabolically active organisms • Its specific contribution to chronic inflammation and scarring in human ocular trachoma remains incompletely established.
Step 5 – Tarsal Scarring and Corneal Sequelae• Repeated trachomatous inflammation can produce scarring of the upper tarsal conjunctiva, classified as trachomatous scarring • Progressive cicatricial eyelid distortion can cause entropion • An upper eyelash touching the eyeball, or evidence of recent epilation of an in-turned upper eyelash, is classified as trachomatous trichiasis • Repeated mechanical trauma or abrasion of the ocular surface and cornea can cause corneal scarring and opacity • Corneal scarring and opacity can cause visual impairment or blindness • The process commonly spans decades.
KEY MECHANISM - EXAM TRAP
  • Blindness in trachoma is primarily a late cicatricial sequela of recurrent infection-associated inflammation.
  • Repeated reinfections can contribute to recurrent severe conjunctival inflammation and progressive cicatricial scarring, although established scarring may continue to progress even when ongoing infection is not detectable.
  • Conjunctival scarring causes trachomatous trichiasis, and repeated corneal abrasion can lead to corneal opacity and visual loss.
  • Early treatment does not reverse established blindness but can prevent progression; advanced trachomatous trichiasis may require surgery to prevent further corneal damage.

Chlamydial Inclusion Bodies - Pathology Correlation

  • On Giemsa staining: basophilic paranuclear inclusions in conjunctival epithelial cells = 'Halberstaedter-Prowazek bodies'.
  • On iodine staining: brownish inclusions (due to glycogen in inclusion).
  • These are seen on conjunctival scraping - a classic examination question.

3. Clinical Features & Grading Systems

Exam pearl
  • Clinical Analogy: Imagine the upper tarsal conjunctiva as a freshly plastered wall.
  • Trachoma first causes roughening (follicles), then cracks appear (linear scars), then the wall collapses inward (entropion/trichiasis), and finally the window (cornea) gets scratched opaque.

MacCallan Classification

StageNameFeaturesWorld Health Organization (WHO)-related sign / qualification
Stage IIncipient Trachoma• Incipient trachoma • Hyperaemia of the palpebral conjunctiva• No exact World Health Organization (WHO) equivalent • World Health Organization (WHO) trachomatous inflammation - follicular (TF) requires ≥5 follicles, each ≥0.5 mm, in the central upper tarsal conjunctiva
Stage IIaEstablished – follicular• Follicles predominate• No exact World Health Organization (WHO) equivalent • World Health Organization (WHO) trachomatous inflammation - follicular (TF) may be present only when the World Health Organization (WHO) TF criteria are met
Stage IIbEstablished – papillary• Follicles + papillary hypertrophy • Papillae predominate• World Health Organization (WHO) trachomatous inflammation - intense (TI) is a rough clinical correspondence only
Stage IIcComplicated established trachoma• Complicated by chronic gonococcal conjunctivitis• No World Health Organization (WHO) equivalent
Stage IIICicatricial Trachoma• Cicatrization begins• World Health Organization (WHO) trachomatous scarring (TS) is the closest related sign, but not an exact stage equivalent
Stage IVHealed/complete cicatrization• Complete cicatrization • Residual conjunctival scarring and sequelae may remain• World Health Organization (WHO) trachomatous scarring (TS), trachomatous trichiasis (TT), and corneal opacity (CO) are separate signs that may coexist • They are not a single formal equivalent of MacCallan Stage IV

World Health Organization (WHO) Simplified Grading System

This is the World Health Organization (WHO) field grading system used for community-based epidemiological surveys and trachoma elimination programmes.

GradeFull NameDiagnostic CriteriaMinimum
Trachomatous Inflammation - Follicular (TF)Trachomatous Inflammation - Follicular (TF)• ≥5 follicles (≥0.5 mm) in the central upper tarsal conjunctiva• 5 follicles or more
Trachomatous Inflammation - Intense (TI)Trachomatous Inflammation - Intense (TI)• Pronounced inflammatory thickening of the upper tarsal conjunctiva obscuring >50% of the deep tarsal vessels• >50% vessel obscurity
Trachomatous Scarring (TS)Trachomatous Scarring (TS)• Easily visible scarring in the upper tarsal conjunctiva • White lines, bands, or sheets• Easily visible scar
Trachomatous Trichiasis (TT)Trachomatous Trichiasis (TT)• At least 1 eyelash from the upper eyelid touching the eyeball • OR evidence of recent epilation of in-turned upper-eyelid eyelashes• 1 lash touching the eyeball
Corneal Opacity (CO)Corneal Opacity (CO)• Easily visible corneal opacity • Dense enough that at least part of the pupil margin is blurred when viewed through the opacity• At least part of pupil margin blurred

Grading Trap

  • Trachomatous inflammation - follicular (TF) and trachomatous inflammation - intense (TI) represent ACTIVE disease (infectious stage); trachomatous scarring (TS), trachomatous trichiasis (TT), and corneal opacity (CO) represent SEQUELAE (cicatricial stage).
  • Importantly, trachomatous inflammation - follicular (TF) and trachomatous inflammation - intense (TI) may coexist simultaneously (grade both separately). Corneal opacity (CO) is a late-stage sequela/sign in the World Health Organization simplified trachoma grading system.
  • Corneal opacity (CO) alone does not establish active inflammatory trachoma; it indicates advanced corneal involvement and may impair vision.

Clinical Signs - Detailed Description

Follicles and Papillae

  • Follicles: Round, pale or yellow-white elevations beneath the superficial epithelium; for trachomatous inflammation - follicular (TF) grading, five or more follicles, each at least 0.5 mm in diameter, must be present in the central upper tarsal conjunctiva.
  • The cited 0.5–2 mm range and description as avascular are not required for World Health Organization (WHO) grading.
  • Superior limbal follicles may resolve leaving Herbert’s pits, which are a highly specific (pathognomonic) sign of past trachomatous inflammation.
  • Trachomatous follicles are organized lymphoid follicles composed predominantly of B cells forming the germinal centre/core, with surrounding lymphocytes including T cells and other inflammatory cells.
  • For World Health Organization (WHO) grading, only follicles in the central part of the upper tarsal conjunctiva are significant for trachomatous inflammation - follicular (TF); follicles elsewhere, including peripheral or fornix follicles, may occur and are not by themselves sufficient for trachomatous inflammation - follicular (TF).
  • Papillae: Red, vascular elevations with central capillary loop surrounded by inflammatory cells. More nonspecific than follicles.

World Health Organization (WHO) Inflammatory Grading and Scarring

  • trachomatous inflammation - intense (TI) is defined by pronounced inflammatory thickening of the upper tarsal conjunctiva that obscures more than half of the normal deep tarsal vessels; it should not be defined solely as predominance of papillae or as an ‘intense inflammatory load.’
  • Herbert’s Pits: Depressed, round, thinned areas at the superior limbus resulting from regression or healing of limbal follicles.
  • Herbert’s pits are late sequelae of regressed limbal follicles.
  • Older McCallan classifications describe them in cicatrizing or healed trachoma (stages III–IV), but the current World Health Organization (WHO) simplified grading system does not assign them a separate stage.
  • Herbert’s pits are highly specific for trachoma in the appropriate clinical context.
  • Arlt’s Line: Horizontal linear scar of the upper tarsal conjunctiva, located in the watershed region between the marginal and peripheral conjunctival vascular supplies and running parallel to the lid margin.
  • Arlt’s line is a classical or characteristic sign of trachomatous upper-tarsal conjunctival scarring; it should not be described as pathognomonic.
  • Named after Carl Ferdinand Ritter von Arlt (Carl Ferdinand von Arlt).

Corneal Findings

  • Pannus: Fibrovascular ingrowth from the superior limbus or upper cornea onto the cornea.
  • Superior or upper-pole pannus is a characteristic corneal finding of trachoma. Pterygium typically arises in the interpalpebral zone and is more commonly nasal, although it may also occur temporally.
  • Early pannus may be thin or incipient; with progression it may become thick and densely vascularized or opaque. These descriptive terms are not a formal World Health Organization staging system.
  • Corneal Vascularization: Trachomatous corneal pannus is an upper-pole fibrovascular change that may extend from the limbus into the cornea.
  • Corneal opacity may result from direct trauma by trachomatous trichiasis or secondary bacterial infection; the reviewed sources do not establish an invariant sequence in which superficial stromal vessels begin superiorly and progress centrally.

Trichiasis, Concretions, and Dry Eye

  • Trichiasis: Misdirected eyelashes touching the globe.
  • In trachoma, repeated inflammation and tarsal conjunctival scarring can cause entropion, allowing eyelashes to touch the globe. Other causes of trichiasis exist, but a metaplastic-lash mechanism without frank entropion should not be stated as an established trachomatous mechanism without a specific supporting source.
  • Trichiasis severity may be described by the number and location of lashes touching the globe; commonly used categories include minor trichiasis (1–5 lashes) and major trichiasis (more than 5 lashes). ‘Total,’ ‘partial,’ and ‘monofascicular’ are not standard WHO simplified grading categories.
  • Concretions: Small yellow-white or yellowish deposits, usually composed of degenerating epithelial cells and proteinaceous secretions; they may undergo calcification but should not be described uniformly as calcium deposits in conjunctival crypts.
  • Concretions should be distinguished from follicles, which are rounded lymphoid lesions. They may occur in chronic trachomatous inflammation, but ‘healed/cicatricial stage’ is not a formal WHO grading designation for concretions.
  • Dry Eye: Trachomatous conjunctival scarring is associated with depletion of conjunctival goblet cells and destruction of accessory lacrimal gland tissue, contributing to ocular-surface dryness.
  • These changes can reduce tear-film volume and stability, contributing to ocular-surface dryness. Dry eye and trichiasis can contribute to recurrent corneal erosions, secondary infection, and progressive corneal opacity.
VIVA PEARLS
  • Herbert's Pits + Arlt's Line = PATHOGNOMONIC combination for trachoma - cite both in any viva.
  • Superior pannus in trachoma vs. inferior pannus in other conditions (e.g., superior limbic keratoconjunctivitis (SLK) - ALSO superior pannus but superior limbic keratoconjunctivitis (SLK) has no tarsal follicles).
  • Follicles must be ≥0.5 mm (pinhead size). Smaller follicles do not count toward trachomatous inflammation - follicular; their presence alone should not be described as a normal follicular response. Count only those in the CENTRAL upper tarsus, not at the margins.
  • Trachomatous inflammation - intense (TI) alone (without trachomatous inflammation - follicular) is still a separately graded sign of active trachoma; because trachomatous inflammation - intense (TI) has lower specificity than the follicular pattern, consider other causes of severe conjunctival inflammation.
  • Concretions in trachoma ≠ follicles - they are deeper, harder, and may scratch the cornea mechanically (another mechanism of corneal damage).

4. Investigations & Laboratory Diagnosis

  • Trachoma is primarily a clinical diagnosis in endemic settings.
  • Laboratory investigations are used for:
  • • Confirmation
  • • Research
  • • Surveillance
TestMethodFinding/ResultNotes
Conjunctival smear - Giemsa stain• Epithelial cells from upper tarsal scraping• Intracytoplasmic basophilic inclusions (Halberstaedter–Prowazek bodies) in epithelial cells• Sensitivity 30–60% • Least sensitive method • Superseded by more sensitive diagnostic techniques
Conjunctival smear - iodine stain• Same specimen as the Giemsa stain• Brown paranuclear inclusions (glycogen in reticulate bodies)• Simpler • Identifies inclusions
Cell culture (McCoy or HeLa cells)• Conjunctival swab in cold-chain transport medium • Inoculation onto McCoy or HeLa 229 cells• Chlamydial inclusions in tissue culture• Highly specific • Sensitivity approximately 50–70% • Technically complex • Requires cold-chain transport and 48–72 hours • Generally impractical for routine field use
Polymerase chain reaction (PCR) / nucleic acid amplification test (NAAT)• Conjunctival swab• Detects chlamydial DNA • Targets may include the major outer membrane protein (MOMP) gene and omp1 gene• Sensitivity approximately 90–100% in reported ocular comparisons • Useful for research and surveillance • Performance depends on assay target, specimen quality, and validation • Real-time polymerase chain reaction may provide rapid testing
Direct immunofluorescence (DIF)• Conjunctival smear • Fluorescein-labelled antibody against the major outer membrane protein (MOMP) or other chlamydial antigen• Fluorescent elementary bodies detected by fluorescence microscopy• Sensitivity approximately 60–80% • Processing time about 30 minutes • Requires a fluorescence microscope and experienced microscopist
Serology• Serum or tears• Anti-chlamydial immunoglobulin A (IgA), immunoglobulin G (IgG), or immunoglobulin M (IgM)• Poor specificity and reproducibility • Does not reliably distinguish ocular from genital infection • Limited use
Rapid antigen tests (for example, Clearview)• Conjunctival swab• Chlamydial antigen• Can be used in field settings • Sensitivity varies by assay and setting • Not recommended as the sole basis for diagnosis or surveillance decisions
Slit-lamp examination / anterior segment optical coherence tomography (AS-OCT)• Clinical examination or selected cross-sectional imaging• Clinical assessment of conjunctival scarring and corneal opacity • Anterior segment optical coherence tomography may characterize ocular-surface lesion depth or pannus-like tissue• Slit-lamp examination supports clinical evaluation • Anterior segment optical coherence tomography is not a routine trachoma diagnostic test • Research and selected adjunctive assessment or surgical planning
Specimen collection and interpretation• Collect conjunctival material from the clinically affected upper tarsal conjunctiva when laboratory testing is required• Test results depend on specimen quality, collection technique, assay target, and transport conditions• Laboratory results supplement, but do not replace, clinical assessment in endemic settings

Viva Pearls

  • In clinical practice: trachoma is a FIELD DIAGNOSIS - World Health Organization (WHO) grading with 2.5× loupe in natural daylight is the standard tool. No laboratory test required for treatment decisions.
  • Polymerase chain reaction (PCR)/nucleic acid amplification testing (NAAT) is a complementary research and surveillance tool. Trachoma programme decisions have traditionally been based on trachomatous inflammation - follicular (TF) prevalence surveys, while complementary diagnostic indicators are being evaluated for surveillance and programme use.
  • Giemsa smear sensitivity is highest in acute/active trachoma (trachomatous inflammation - follicular [TF]/trachomatous inflammation - intense [TI]) and very low in scarred stages (trachomatous scarring [TS]/trachomatous trichiasis [TT]) - because infection may have resolved.
  • Halberstaedter-Prowazek (H-P) bodies are the diagnostic inclusions on Giemsa - the same terminology is used for Chlamydia trachomatis in ocular specimens and in related genital or neonatal inclusion infections.
  • Positive culture confirms viable organism. Positive polymerase chain reaction (PCR) may persist even after antibiotic treatment because of nonviable-organism DNA - interpret with clinical context.

5. WHO Safe Strategy - The Framework of Elimination

Exam pearl
  • Clinical Analogy: SAFE is an integrated four-part approach to trachoma elimination - Surgery corrects trachomatous trichiasis and prevents further corneal damage; Antibiotics clear ocular Chlamydia trachomatis infection and reduce community transmission; Face washing reduces transmission; and Environmental improvement, particularly improved access to water, sanitation and hygiene, reduces transmission and supports sustained progress.
ComponentTargetInterventionKey Points
S - SurgeryTrachomatous trichiasis (TT)• Bilamellar Tarsal Rotation (BLTR) • Posterior Lamellar Tarsal Rotation (PLTR)• Priority: prevent corneal blindness in those with trachomatous trichiasis (TT) • Surgery prevents further corneal damage, pain and vision loss from trichiasis • Established corneal opacity (CO) is not reliably reversed by trichiasis surgery
A - AntibioticsTrachomatous inflammation - follicular (TF), trachomatous inflammation - intense (TI)• Azithromycin 20 mg/kg single oral dose (maximum 1 g) for mass drug administration (MDA) • Topical tetracycline 1% ointment BD twice daily × 6 weeks (alternative)• Usually annual mass drug administration (MDA) in eligible evaluation units • Duration determined by prevalence or impact surveys • Treats active ocular Chlamydia trachomatis infection and reduces community transmission
F - Face WashingAll ages, endemic communities• Clean face with soap and water • Remove ocular/nasal discharge• Reduces fly attraction • Breaks transmission cycle • Behaviour-change programmes
E - Environmental ImprovementCommunity level• Sanitation (latrines) • Clean water supply • Fly control (insecticides, waste disposal)• Reduces environmental risk factors for transmission • Musca sorbens breeds in open defecation • Supports trachoma elimination

Antibiotic Strategy - Detailed

DrugRegimenAdvantageLimitation
Azithromycin (oral)• 20 mg/kg (maximum 1 g) single dose • Mass drug administration commonly administered annually when indicated • In evaluation units with trachomatous inflammation - follicular prevalence ≥10%, annual district-wide mass drug administration for at least 3 years, followed by re-survey • Frequency determined by local prevalence and World Health Organization programme guidance• Single dose facilitates delivery • Well tolerated by children and adults• Cost • Supply-chain logistics • Resistance concerns (emerging)
Tetracycline 1% eye ointment• Twice-daily application for 6 weeks • Both eyes• Alternative when oral azithromycin is unavailable • Avoids oral systemic azithromycin exposure• Poor adherence to the 6-week regimen

Mass Drug Administration (MDA) Decision Criteria

  • Initiate Mass Drug Administration (MDA) if: trachomatous inflammation - follicular (TF) prevalence ≥5% in children aged 1–9 years (evaluation-unit level).
  • Offer annual antibiotics as directed by current World Health Organization guidance; after the planned Mass Drug Administration (MDA) rounds, an impact survey determines whether treatment can stop;
  • Followed by surveillance if Mass Drug Administration (MDA) is stopped.
  • World Health Organization recommends community-level Mass Drug Administration (MDA) rather than targeted treatment of only clinically affected individuals because it reaches people regardless of disease status and helps reduce untreated reservoirs and ongoing transmission.

Surgical Management of Bilamellar Tarsal Rotation (BLTR)

  • Bilamellar Tarsal Rotation (BLTR) - a World Health Organization (WHO)-endorsed procedure:
  • Anesthesia: Local anesthetic injection with lidocaine 2% (with or without adrenaline) into the upper eyelid
  • Skin incision: Incise skin and muscle parallel to the lid margin, 3 mm above it, to just superficial to the tarsal plate; then incise the everted conjunctiva and tarsal plate through full thickness at the same level and unite the incisions.
  • Tarsal division: Full-thickness cut through tarsus creates proximal and distal tarsal segments
  • Rotation: The distal tarsal fragment with the lid margin is rotated outward; three sutures are used to secure the rotation.
  • Suturing: 4/0 silk is suitable for the Bilamellar Tarsal Rotation (BLTR) sutures.
  • Suturing: Sutures are anchored through the conjunctival surface and proximal tarsal fragment, pass over the distal tarsal plate, and exit through the skin near the eyelashes.
  • Result: Lashes are rotated away from the cornea so they no longer rub on it.

BLTR vs. PLTR - Know the Difference

  • Bilamellar Tarsal Rotation (BLTR): Full-thickness lid incision; both lamellae rotated together as a unit.
  • World Health Organization (WHO)-endorsed alternative procedure.
  • Simple, fast, can be done by trained non-physicians in field settings.
  • Recurrence varies by study, population, surgical technique, and follow-up.
  • One prospective cohort reported 25.0% at 12 months.
  • Posterior Lamellar Tarsal Rotation (PLTR): Incision through conjunctiva and tarsus only (NOT skin).
  • The posterior lamella is incised and dissected; everting sutures rotate the eyelid margin and lash-bearing segment outward.
  • It is a World Health Organization (WHO)-endorsed alternative procedure.
  • Other lid procedures require procedure-specific evidence and appropriate training.
SURGICAL DECISION TRAP
  • World Health Organization (WHO) recommends surgery for confirmed trachomatous trichiasis even in the absence of active trachoma (trachomatous inflammation - follicular or trachomatous inflammation - intense).
  • The scarring–entropion–trichiasis cascade can persist and progress after active infection has subsided.
  • Do not wait for active disease to resolve before offering surgery.
  • Surgery reduces ongoing lash-related corneal injury and prevents further corneal damage.
  • Surgery does not reverse established, irreversible corneal opacity or severe vision loss.

Surgical Complications of BLTR:

  • Recurrence/residual trichiasis: Cumulative postoperative trachomatous trichiasis was 22% at 12 months after bilamellar tarsal rotation (BLTR) versus 13% after posterior lamellar tarsal rotation in a large randomized trial; recurrence was associated with major preoperative trichiasis and technical factors, including undercorrection.
  • Lid notching: A postoperative eyelid-contour abnormality after bilamellar tarsal rotation (BLTR); attribution to incomplete approximation or an irregular incision is not established here.
  • Wound dehiscence: A postoperative complication; the identified evidence does not establish premature suture loss as its cause or show that it is more common in field settings.
  • Contour irregularity: A postoperative eyelid-contour abnormality that may affect eyelid appearance and function.
  • Inadequate rotation: Inadequate rotation of the distal terminal tarsal strip; a recognized technical contributor to postoperative trachomatous trichiasis.
  • Granuloma formation: Can be associated with irregular incision, wound-edge defects from inadequate suturing, and irregular suture tension; absorbable sutures were associated with less frequent granuloma formation than silk in pooled trial data.

6. Complications, Corneal Sequelae & Advanced Management

Complications by Stage

StructureComplicationMechanism
Conjunctiva• Dry eye (keratoconjunctivitis sicca (KCS)) • Symblepharon • Fornix shortening • Concretions• Conjunctival scarring with reduced tear-film volume and goblet-cell depletion • Fibrous scarring causing adhesions and fornix shortening
Eyelid• Cicatricial entropion • Trichiasis • Distichiasis • Ptosis• Tarsal scarring → posterior lamella shortening → lid inversion • Misdirected lashes (trichiasis) • Additional row of lashes arising from or near meibomian-gland orifices (distichiasis)
Cornea• Superior pannus • Keratitis • Corneal ulceration • Corneal opacity (leukoma/nebula/macula) • May cause visual impairment or blindness• Trichiasis-related abrasion and secondary infection can cause corneal ulceration and opacity • Fibrovascular pannus represents corneal fibrovascular change associated with trachoma
Nasolacrimal• Canalicular occlusion • Nasolacrimal-duct obstruction • Epiphora • Dacryocystitis• Cicatrizing changes causing lacrimal drainage obstruction
Ocular surface• Persistent epithelial defects• Mechanical recurrent corneal surface injury from trichiasis

Corneal Opacity Management

Once corneal opacity causing visual impairment is established, treatment of the underlying infection or trichiasis will not restore vision. Optical rehabilitation options:

  1. Control trichiasis first: Before any corneal surgery, appropriate trichiasis surgery should be performed. Operating on cornea with active trichiasis risks graft failure.
  2. Treat ocular surface disease: Preoperative management of dry eye and ocular-surface disease is important. Selected patients may require punctal occlusion or cautery, with treatment individualized before keratoplasty.
  3. Optical iridectomy: For central opacities with clear peripheral cornea. Does not require a corneal graft and may provide variable visual improvement when a clear peripheral visual axis is available.
  4. Penetrating keratoplasty: A keratoplasty option for central dense leukoma when the opacity involves the full corneal thickness. The choice of penetrating versus lamellar keratoplasty depends on corneal depth and ocular-surface status. High failure risk in trachoma due to dry eye and ocular-surface disease, lid abnormalities including trichiasis, and corneal neovascularization. Reliable postoperative follow-up and access to medication are also important. Reported graft-survival outcomes are heterogeneous and based on retrospective studies with variable follow-up.
  5. Boston keratoprosthesis type 1: May be considered in patients with multiple failed grafts or vascularized corneas, provided there is adequate tear production, eyelid function, and a relatively stable ocular surface. Emerging option in low- and middle-income countries.
  6. Limbal stem-cell transplantation: May be considered for confirmed limbal stem-cell deficiency associated with chronic trachoma; chronic microtrauma from lid abnormality contributes to its pathogenesis. If penetrating keratoplasty is required after limbal stem-cell transplantation, sequential surgery after ocular-surface stabilization is generally preferred over simultaneous surgery.

Surgical Priority in Trachoma Blindness

  • Management priorities:
  • (1) Manage active infection with antibiotics when indicated.
  • (2) Correct trachomatous trichiasis with appropriate eyelid surgery when indicated.
  • (3) Treat ocular surface [lubricants/punctal plugs].
  • (4) Corneal surgery [penetrating keratoplasty (PKP)/keratoprosthesis (KPro)].
  • Sequence and surgical choice should be individualized; manage persistent trachomatous trichiasis before addressing corneal opacity.

Pannus - Grading

Pannus extension measured vertically from the upper limbus.
Pannus extension measured vertically from the upper limbus.
GradeExtentDescription
Grade 0• <2 mm from limbus• Pannus extending <2 mm from limbus
Grade 1• 2 to <4 mm• Pannus extending 2 to <4 mm from limbus
Grade 2• 4 to <6 mm• Pannus extending 4 to <6 mm from limbus
Grade 3• ≥6 mm• Pannus extending ≥6 mm from limbus

7. Differential Diagnosis & Comparison Tables

Follicular Conjunctivitis - Differential Diagnosis

The key clinical challenge is distinguishing trachoma from other causes of follicular conjunctivitis:
The key clinical challenge is distinguishing trachoma from other causes of follicular conjunctivitis:
FeatureTrachomaAdult Inclusion Conj.Viral (Adeno)MolluscumParinaud's
Pathogen• Chlamydia trachomatis A, B, Ba, C• Chlamydia trachomatis D–K• Adenovirus• Poxvirus• Cat-scratch disease caused by Bartonella
Location of follicles• Upper tarsus (CRITICAL)• Lower tarsus/fornix• Lower fornix > upper• Lower fornix• Both tarsi, fornix
Superior pannus• YES (characteristic)• No• No• No• No
Herbert's pits• YES (pathognomonic)• No• No• No• No
Arlt's line• YES (characteristic of advanced trachomatous conjunctival scarring)• No• No• No• No
Scarring• Common (cicatricial)• Rare (mild)• No• No (after lid lesion removed)• Uncommon
Preauricular lymph nodes• Present (mild)• Prominent• Prominent• Absent• LARGE (hallmark)
Systemic / skin finding• None• Genital discharge• Upper respiratory tract infection (URTI); epidemic keratoconjunctivitis (EKC): pseudomembrane• Umbilicated lid nodule• Cat scratch, fever
Bilateral• Almost always bilateral• Often unilateral• Usually bilateral• Unilateral or bilateral• Unilateral
Laboratory findings• Giemsa: Halberstaedter–Prowazek (H-P) bodies (epithelial)• Giemsa: Halberstaedter–Prowazek (H-P) bodies (epithelial)• Giemsa: lymphocytes, no inclusions• Intracytoplasmic inclusions (Henderson-Paterson bodies)• Serology, culture for Bartonella

Additional High-Yield Differentials

  • Follicles are more predictive of trachoma in endemic communities.
  • Moraxella species
  • Streptococcus pneumoniae
  • Herpes simplex virus
  • Pediculosis palpebrarum
  • Toxic conjunctivitis
  • Vernal keratoconjunctivitis

Trachoma vs. Other Cicatricial Conjunctivitis

FeatureTrachomaOcular cicatricial pemphigoid/mucous membrane pemphigoid (OCP/MMP)Stevens-JohnsonChemical Burn
- Primary scar site- Upper tarsus (superior)- Inferior fornix - Superior (progressive)- Conjunctiva - Skin - Mucosa- Limbus (limbal stem-cell deficiency (LSCD)) - Variable
- Fornix involvement- Late/severe only- Inferior fornix shortening - Progressive- Yes (acute phase)- Limbal - Fornix
- Bilateral- Yes- Yes (asymmetric)- Yes (symmetric)- Depends on exposure
- Systemic features- No- Skin blistering - Sensorineural hearing loss (SNHL)- Mucocutaneous blistering - DRUGS- Usually no systemic features from isolated ocular exposure - Systemic effects depend on the chemical and route of exposure
- Herbert's pits- YES- No- No- No
- Treatment- Azithromycin - Bilamellar tarsal rotation (BLTR)- Immunosuppressives - Dapsone- Supportive - Amniotic membrane- Irrigation - Surgery

Viva Pearls

  • Adult inclusion conjunctivitis (AIC) = Chlamydia trachomatis serovars D–K; usually sexually acquired; marked tarsal follicles.
  • Ocular cicatricial pemphigoid (OCP) can cause inferior fornix shortening; trachomatous scarring occurs in the upper tarsal conjunctiva.
  • Parinaud oculoglandular syndrome: unilateral granulomatous follicular conjunctivitis with ipsilateral preauricular and/or submandibular lymphadenopathy.
  • In a young child from an endemic area, assess superior tarsal follicles using the World Health Organization criteria for trachomatous inflammation - follicular: at least five follicles, each at least 0.5 mm, in the central upper tarsal conjunctiva.
  • Do not treat adult inclusion conjunctivitis with topical antibiotics alone. Use systemic treatment, such as oral azithromycin or doxycycline, and ensure sexual partners are evaluated and treated.

8. · High-Yield MCQs, Viva Traps & Advanced Questions

MCQ

A 6-year-old child in rural Rajasthan has five follicles, each at least 0.5 mm in diameter, in the central part of the upper tarsal conjunctiva, with mild papillary reaction and no scarring. This meets the World Health Organization definition of trachomatous inflammation - follicular, and the evaluation-unit prevalence is at least 5% in children aged 1–9 years. What is the MOST appropriate immediate management?

MCQ

A 45-year-old woman presents with trachomatous trichiasis and dense central corneal leukoma causing hand-motion vision. No active trachomatous follicles or intense inflammation. What is the correct management sequence?

MCQ

Which of the following is PATHOGNOMONIC of healed/cicatricial trachoma on slit-lamp examination?

MCQ

Which Chlamydia trachomatis serovars cause epidemic trachoma?

MCQ

Following an impact survey, what trachomatous inflammation - follicular (TF) prevalence in children aged 1–9 years triggers transition from mass drug administration (MDA) to post–mass drug administration (MDA) surveillance?

MCQ

A conjunctival smear from a 4-year-old with active trachoma is stained with Giemsa. Which cell predominantly shows inclusions?

MCQ

In the WHO SAFE strategy, which component directly addresses the VECTOR of transmission?

MCQ

A 35-year-old woman in an evaluation unit currently receiving mass drug administration has Arlt's line and trichiasis but no follicles. Polymerase chain reaction of a conjunctival swab is negative. Should she receive azithromycin?

9. Viva Follow-Up Questions

VIVA FOLLOW-UP QUESTIONS - GRADUATED DIFFICULTY
Q1

What is the difference between trachomatous inflammation - follicular (TF) and trachomatous inflammation - intense (TI) in the World Health Organization grading? Can both be present simultaneously?

Q2

Why are women more susceptible to trachomatous trichiasis than men in endemic communities?

Q3

Explain why topical antibiotic treatment alone is less suitable than community-wide oral azithromycin mass drug administration for trachoma control.

Q4

A patient with trachomatous corneal leukoma undergoes penetrating keratoplasty. The graft fails at 6 months. What factors specific to trachoma predispose to graft failure?

Q5

Discuss the emerging concept of persistent trachoma and its implications for mass drug administration (MDA) programmes globally.

10. Advanced Consultant-Level Extension Question

Consultant-level oral-exam question

A district in sub-Saharan Africa has received 5 annual rounds of mass drug administration (MDA) with azithromycin achieving >85% coverage each year. A post-mass drug administration (MDA) survey using polymerase chain reaction (PCR) finds 8% ocular C. trachomatis prevalence in children 1–9 years, but clinical trachomatous inflammation - follicular (TF) by World Health Organization (WHO) grading is only 3%. The program coordinator asks whether to continue mass drug administration (MDA). As a consultant, how do you interpret this discordance, what are the possible explanations, and what is your recommendation?

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