Research draft

trachoma

vr.tr.trachoma · XCT.STA

Enable an AI agent to recognise evidence of trachoma, distinguish current inflammation and infection from lasting ocular damage, and support appropriate clinical referral and population-control decisions.

Thing Registry Cross-cutting context

Research draft, second pass

A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.

Researched by: Codex

Purpose and description

It can be Organise examination and laboratory evidence into a traceable trachoma assessment.; Compare dated eye examinations to identify new inflammation, scarring or recurrent lash contact.; Flag findings requiring clinician assessment and track referral completion.; Support authorised selection and monitoring of trachoma interventions using applicable guidance.; Aggregate eligible observations into population indicators with explicit denominators and uncertainty.; Identify evidence gaps that prevent a diagnosis, treatment decision or elimination claim..

Distinguishing features

Examine the upper tarsal conjunctiva: redness or discharge alone does not establish trachoma; record the distribution of follicles, inflammation and scarring.

Apply explicit grading criteria: WHO TF requires at least five follicles of at least 0.5 mm in the central upper tarsal conjunctiva. [WHO diagnosis](https://www.who.int/teams/control-of-neglected-tropical-diseases/trachoma/diagnosis)

Distinguish clinical trachoma from laboratory-detected ocular chlamydial infection; a positive organism test alone does not establish the characteristic disease history or exclude another chlamydial conjunctivitis presentation.

For lashes touching the eye or corneal opacity, record evidence of a trachomatous cause and competing explanations rather than attributing all trichiasis or opacity to trachoma.

Keep active inflammatory signs separate from established scarring and mechanical damage; an eye with lasting sequelae need not have demonstrable current infection.

Scope

+ Clinical evidence supporting or challenging attribution to trachoma

+ Independent recording of active inflammation, conjunctival scarring, trichiasis and corneal opacity in each eye

+ Ocular infection evidence and its relationship to clinical signs

+ Repeated exposure, disease progression and trachoma-attributable visual impairment

+ Indications, delivery and outcomes of trachoma-specific interventions

+ Population burden, surveillance and evidence supporting elimination assessments

- General classification and management of conjunctivitis from other causes

- Urogenital chlamydial infection and its sexual-health management

- The complete biology and taxonomy of Chlamydia trachomatis

- Detailed surgical technique, prescribing protocols and pharmaceutical supply chains

- General water, sanitation and housing infrastructure design

- Comprehensive blindness rehabilitation and unrelated causes of visual impairment

Characteristics

Assessment subject and laterality: Person and right or left eye; population observations linked separately to a defined evaluation unit Prevents one eye's findings or a district's prevalence from being assigned to another eye or to an individual.
Trachoma attribution: Suspected, supported, uncertain or alternative explanation favoured; record the case definition and evidence Makes the basis of recognition explicit without inventing a universal confirmation rule.
Simplified clinical signs: TF, TI, TS, TT and CO independently present, absent, uncertain or not assessed for each eye These signs can coexist and should not be forced into a single sequential stage.
Ocular infection evidence: Detected, not detected, indeterminate or not tested; specimen site, assay and collection date Separates microbiological evidence from inflammatory signs and historical damage.
Lash contact and epilation: Number and location of upper-lid lashes touching the globe; evidence and timing of recent epilation Documents mechanical risk and avoids interpreting removed lashes as resolution of the underlying problem.
Visual function: Visual acuity per eye using a named scale, correction status and assessment date Tracks functional consequences while preserving uncertainty about their cause.
Exposure and intervention history: Dated links to residence, household exposure, prior examinations, antibiotics, epilation and eyelid surgery Supports interpretation of recurrence, persistent damage and possible reinfection.
Population burden: Indicator-specific prevalence in percent, with numerator, denominator, age group, survey date, uncertainty and evaluation unit Keeps estimates comparable and prevents an unrepresentative case count from becoming a programme decision.
Care pathway status: Assessment needed, referred, offered, accepted, deferred, declined, delivered or follow-up due, with reason and date Distinguishes an identified need from completed care and records unresolved barriers.

Where this came from

wikidata · CC0 1.0

Source repository Registry entry point

Also registered as vr.tr.trachoma

Drafted structure

Bundle to layer to finding to question, as the second pass will find it: 5 bundles · 10 layers · 10 findings · 21 questions.

Recognition and attribution Establish what supports identifying an observation as trachoma and what remains ambiguous.

Follicular conjunctivitis, ocular chlamydial infection and scar-related eyelid disease are overlapping observations rather than interchangeable diagnoses.

Clinical recognition

Connect the observed conjunctival pattern to an explicit recognition rule.

Trachoma case basis

Record the examined eye, observed signs, examiner and case definition supporting attribution.

Which upper tarsal conjunctival findings support trachoma under the stated case definition? definition
Who examined the eye, when, and with what grading training and examination conditions? provenance

Infection and differential

Separate organism detection from disease attribution and consider competing explanations.

Clinical and laboratory concordance

Preserve agreement or disagreement between clinical signs, ocular testing and the exposure history.

What ocular specimen and assay, if any, support current infection, and how does collection timing relate to examination and antibiotics? provenance
What evidence distinguishes this presentation from other follicular conjunctivitides, including other chlamydial ocular presentations? boundary

Ocular signs and damage Describe inflammation and structural consequences independently for each eye.

Current inflammation and established damage imply different needs and cannot be represented reliably by one severity label.

Inflammation and scarring

Record TF, TI and TS separately using a named grading standard.

Independent conjunctival signs

Capture follicles, inflammatory vessel obscuration and visible scarring without assuming every sign must occur in sequence. [WHO grading criteria](https://www.who.int/teams/control-of-neglected-tropical-diseases/trachoma/diagnosis)

For each eye, which TF, TI and TS criteria are present, absent or impossible to assess? measurement
Do differences from earlier examinations reflect changed findings, a different grader or inadequate examination quality? provenance

Mechanical and visual consequences

Connect eyelid abnormalities and corneal findings to functional harm without assuming causation.

Lash, cornea and vision assessment

Record upper-lid lash contact or recent epilation, corneal opacity, visual acuity and evidence for trachomatous attribution.

Which lashes touch the globe, what recent epilation is evident, and what corneal findings and visual acuity are recorded in each eye? measurement
Which evidence links the eyelid or corneal damage to trachoma, and which alternative causes require assessment? boundary
Do pain, new visual loss or suspected corneal injury require expedited clinical assessment under the applicable referral pathway? action

Exposure and disease course Place findings within repeated exposure and a dated history of inflammation and damage.

A single examination cannot establish the history of recurrent exposure or explain persistent sequelae.

Transmission context

Record plausible opportunities for exposure and prevention needs without assigning individual blame.

Ocular secretions and household exposure

Link relevant contact, facial cleanliness, water and sanitation observations to possible transmission opportunities. [WHO trachoma overview](https://www.who.int/news-room/fact-sheets/detail/trachoma)

What dated observations describe contact with ocular or nasal secretions, household clustering and residence in affected communities? provenance
Which observed barriers to facial cleanliness, water access or sanitation could a prevention programme address? action

Longitudinal course

Distinguish persistent signs, newly observed disease and sequelae after treatment.

Persistence, recurrence and progression

Compare dated clinical and infection evidence while leaving unobserved intervals and mechanisms unresolved.

Which examinations document resolution, persistence, new scarring or recurrent lash contact? measurement
What evidence supports reinfection, persistent infection, residual inflammation or postoperative recurrence, and what remains indistinguishable? boundary

SAFE interventions and follow-up Connect identified needs to surgery, antibiotics, facial cleanliness and environmental improvement under the SAFE strategy. [WHO prevention and control](https://www.who.int/news-room/fact-sheets/detail/trachoma)

Infection control, protection from lash-related injury and prevention of further exposure require distinct actions and outcome measures.

Intervention selection

Identify which action is supported, at which level, and by whose authority.

Indication and eligibility

Separate individual care indications from population antibiotic decisions and record the applicable protocol.

Which findings support trichiasis referral, individual infection management or assessment for population antibiotic intervention? action
Which current local protocol, eligibility factors and authorised clinician or programme decision govern the proposed intervention? provenance

Delivery and outcomes

Track completed care and reassessment against the problem each intervention addresses.

Care completion and residual need

Record treatment or referral completion, barriers, adverse outcomes and continuing ocular or prevention needs.

Was the indicated intervention offered and delivered, and what explains any delay, refusal or incomplete coverage? action
At follow-up, what evidence shows changed inflammation, infection, lash contact, visual function or continued exposure? measurement

Population burden and elimination Represent survey evidence and programme status separately from individual diagnoses.

Elimination decisions depend on defined populations, indicator-specific evidence and continuing care capacity rather than the absence of reported cases.

Survey indicators

Preserve the age groups, sampling methods and definitions behind trachoma prevalence estimates.

TF and TT population estimates

Distinguish TF prevalence in children aged 1-9 years from TT prevalence in people aged 15 years and older, including the required health-system-awareness classification. [WHO trachoma questions and answers](https://www.who.int/news-room/questions-and-answers/item/trachoma)

What are the evaluation unit, survey dates, sampling method, age-specific denominators and uncertainty for each estimate? measurement
How were TT cases classified with respect to being known to the health system, and were grading and adjustment methods comparable across surveys? provenance

Programme status and surveillance

Attach elimination assessments to their governing criteria, geography, date and ongoing surveillance obligations.

Elimination evidence and continuing care

Distinguish elimination as a public health problem from absence of infection or absence of people needing care.

Which dated criteria and evidence support the recorded elimination status, and which authority assessed or validated it? provenance
What system continues to detect and manage incident TT and investigate evidence of renewed transmission? action

What the second pass must settle

Does an existing Vercy world model already own trachoma, requiring vr.tr.trachoma to link to it rather than create another publication?
Which diagnostic and referral rules should resolve discordant clinical signs and ocular infection tests in the intended jurisdictions?
Which evidence is sufficient to attribute trichiasis or corneal opacity to trachoma when conjunctival scarring or reliable history is unavailable?
Which current national and WHO guidance versions govern antibiotic programme decisions, surveillance and elimination assessment for the intended evaluation units?
Which follow-up intervals and outcome definitions should distinguish residual inflammation, reinfection, progressive scarring and postoperative trichiasis?

Draft as JSON