Program-cost scenario · Model v0.1

Relieving persistent eye pain

When eyelashes turn inward and rub against the eye, everyday life can become painful. We explore what trachoma-related trichiasis surgery could relieve during the first year.

A treatment opportunity with a published planning-cost reference.
Reviewed 17 October 2026. A current donation allocation and remaining funding gap have not been verified.

USU of modeled pain reduction

≈20

per $100 in program costs
2025 USD · Central scenario

USU of later eye-pain relief

2.3

USU deducted for assumed treatment pain

The central balance is 19.9 USU: later relief minus a simple recovery allowance. This is an illustrative program-cost calculation, not an estimate of what a new donation buys or a complete net-benefit score.

Lower and higher scenarios give 3.8 and 51.2 USU per $100. These are assumptions, not confidence bounds. If lasting relief is absent, the central recovery allowance makes the balance −2.3 USU. Actual outcomes can be zero or negative.

Why this intervention

Relief that can matter day after day

Repeated trachoma infection can leave scarring that turns the eyelid inward. Surgery changes the lid position to stop lashes rubbing the eye. [T4] This report focuses on physical pain; vision, independence and other benefits remain outside its USU estimate.

A 2017 Ethiopian study enrolled 1,000 adults receiving surgery and followed 980 at one year. Approximately 99% reported eye pain before treatment, compared with 33.7% at follow-up. [T1]

The comparison participants did not have trichiasis. This was not a trial of surgery against leaving affected patients untreated. The findings support investigating relief, but do not establish a causal USU effect, the timing of improvement or outcomes in every program.

Our model therefore uses a stated average pain reduction. We do not turn the change in symptom percentages into a measured USU value.

What the result includes

Included

Average later physical eye-pain relief among adults receiving additional surgery, minus an early treatment-pain allowance applied to all modeled courses. Ongoing symptoms and recurrence belong in the average relief assumption.

Outside this estimate

Vision-related benefits, psychological and family effects, earlier or longer-term relief, the full burden of complications and repeat surgery, and deaths prevented.

Subtracting recovery makes this a balance of selected pain effects, not a complete net-benefit estimate or a guaranteed lower bound. The other WSI opportunity headlines generally report gross benefits and use different cost models and populations. These figures do not establish a ranking.

Explore the estimate

What could a treatment budget help relieve?

For $100 in modeled program costs

19.9USU pain balance

22.2USU later relief

2.3USU treatment-pain deduction

Central: $315 per completed course; 0.5-point average pain reduction for 275 days; 7 days at 2 points for treatment pain. 0.317 modeled course equivalents. All costs use 2025 USD.

The calculator scales linearly to explain the arithmetic. It does not establish how much additional funding a provider can use at this rate. Fractional courses are averages, not partial operations.

This calculator illustrates the model. It does not make a payment or collect a donation.

Per $100 in program costs (2025 USD). All scenarios credit 275 days of later relief.
Scenario	Cost / course	Average pain decrease	Treatment pain	Later relief USU	Deducted USU	Balance USU
Lower	$360	0.25	14 days × 3	9.7	5.9	3.8
Central	$315	0.5	7 days × 2	22.2	2.3	19.9
Higher	$270	1	3 days × 1	51.7	0.6	51.2
No lasting relief	$315	0	7 days × 2	0.0	2.3	-2.3

The scenarios change several choices together. They do not span all possible outcomes or provide statistical bounds. A negative balance means the included treatment pain exceeds the included relief.

Evidence and judgment

What supports the inputs?

Cost: a coalition planning estimate

The International Coalition for Trachoma Control’s 2025 analysis uses $180 per management case, with a further 50–100% for implementation. This yields $270–$360; we use the $315 midpoint. The reference includes outreach, case finding and follow-up costs. [T2]

The report’s term “surgery” also covers other management, including eyelash removal where appropriate. [T3] Using its unit cost for a completed surgical course is our proxy assumption, not a verified surgery-only price. A patient is counted once, including required care for both eyes. Repeated procedures, local case mix and partner contributions could raise the cost.

We retain 2025 USD rather than presenting this as a 2026 quote. TT-only prevalence surveys are excluded from the source cost. [T2] A funded project would need its own budget and delivery check.

Intensity: one average across everyone treated

The central 0.5-point reduction is a WSI judgment. On a linear scale it is equivalent, for illustration, to half of patients averaging a 1-point improvement while the rest average none. It is not a finding about either group.

This single average allows for incomplete response, recurrent symptoms and hours without conscious pain. We therefore do not multiply by a separate success rate. The lower and higher choices are 0.25 and 1 point. All are provisional; the clinical study does not identify the correct value.

Duration: a limited window with an explicit assumption

We credit 275 days, beginning on day 91 and ending on day 365. A one-year follow-up supports examining later outcomes, but does not show that the same relief persisted throughout this interval. No disease-pain relief is credited in the first 90 days or after year one.

Recovery: an explicit deduction

A randomized study comparing surgery with eyelash removal reported greater recalled treatment pain after surgery. [T4] Our 7-day, 2-point allowance is a modeling choice, not a measured average from that study. We test 14 days at 3 points and 3 days at 1 point.

These are additional pain burdens attributable to treatment. They do not price every complication. At the central recovery allowance, an average later reduction of about 0.051 points would balance the included treatment pain. This arithmetic threshold is not evidence that such relief occurs.

Follow the calculation

A simple first-year pain balance

Translate a program budget into completed courses
Use a $315 planning allowance per person. The calculation assumes these courses are additional to the care that would otherwise occur in the credited year.
$100 ÷ $315 = 0.317 course equivalents
Count later pain relief
Assume a 0.5-point average reduction across all treated patients and all hours, including sleep and residual symptoms. Credit postoperative days 91–365 only.
($100 ÷ $315) × 275 days × 24 hours × 0.5 ÷ 47.25
= 22.2 USU of later relief
Deduct an allowance for treatment pain
Apply 7 days at an average additional intensity of 2 to every completed course.
($100 ÷ $315) × 7 days × 24 hours × 2 ÷ 47.25
= 2.3 USU of treatment pain
22.2 − 2.3 = 19.9 USU of modeled pain reduction

Calculations retain full precision before rounding. One USU is the stipulated six-hour kidney-stone pain reference of 47.25 intensity-hours, using linear weighting (p = 1). This unit convention does not validate the intensity choices. Read about the reference

Funding review · 17 October 2026

A documented need, with the next allocation still unverified

The 2025 coalition report estimated a $105–$140 million funding gap to manage about 390,000 people in 13 countries. It excluded committed funding. [T3] This is a historical sector estimate, not a verified remaining balance as of today.

Sightsavers accepts general donations, but says smaller gifts go to its general funds. [T5] We have not established the share of a new gift that would fund additional trichiasis surgery. The calculator consequently applies to modeled program costs, not donations to Sightsavers or another organization.

Explore the organizations doing this work

Read the coalition’s funding analysis →

Explore Sightsavers’ trachoma work →

A donation-linked estimate would require a current delivery budget, a remaining funding gap and evidence of how new funding changes completed treatments. No organization has endorsed this USU model.

Inspect and improve

Sources and reproducible inputs

Habtamu et al. (2017): Impact of trichiasis surgery on daily livingLongitudinal Ethiopian study; abstract and ocular-pain results, Table 6. Follow-up symptoms, not a calibrated intensity or duration estimate.
ICTC (2025): Closing the Gap, appendicesAppendix I, printed pages 2–3: planning unit cost and implementation allowance.
ICTC (2025): Closing the Gap, main reportPrinted pages 4 and 10: 2025 USD, surgery funding gap and definition of management.
Rajak et al. (2011): Surgery versus epilation for minor trichiasisRandomized trial; symptoms section and Table 5. Supports including treatment burden, not our chosen recovery profile.
Sightsavers: Frequently asked questionsGeneral-fund allocation policy, checked 17 October 2026.

Inputs & results (JSON)Reproduce the calculation (ZIP)

The most useful refinements are a current surgery-specific cost per completed patient course, repeated patient-reported pain observations and a clearly identified additional funding opportunity.

Prepared 17 October 2026 · Model v0.1 · Funding recheck due 16 November 2026 or after a material change · Suggest a correction