# OHTS-EGPS 5-year POAG risk

OHTS-EGPS 5-year POAG risk

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/ohts`
HTML: https://magentlab.com/docs/ohts
Markdown: https://magentlab.com/docs/ohts.md

Not a medical device. Not a diagnosis, dose, or listing recommendation.

## What it computes

Compute the OHTS-EGPS 2007 Table 6 5-year primary open-angle glaucoma percent for untreated ocular hypertension from age, mean IOP, mean central corneal thickness, mean vertical cup-disc ratio, and mean Humphrey pattern standard deviation.

## When to use

When an agent already has those five averaged baseline predictors for a person with ocular hypertension aged 30-80 and needs that paper's mapped 5-year POAG percent. Not a glaucoma diagnosis, drop order, or Gordon 2002 univariate table.

## When not to use

- Not a medical device. Not a diagnosis of glaucoma. Not a drop order or treatment recommendation.
- Table 6 point system printed in Ophthalmology 2007 only. The paper's continuous Cox estimate (16.9% in the worked example) is not implemented: 5-year baseline survival and centering constants are not printed.
- No race parameter: African ancestry dropped out of the multivariate model once cup-disc ratio and corneal thickness were included. No diabetes or treatment term.
- Caller assigns age, IOP, pachymetry, disc, and Humphrey PSD. magent does not measure IOP or pachymetry and does not run perimetry. Clamps: age 30-80, IOP 20-32 mm Hg, CCT 475-650 microns.

## Formula

```
OHTS-EGPS 2007 Table 6 points: age <45=0, 45 to <55=1, 55 to <65=2, 65 to <75=3, >=75=4; mean IOP mm Hg <22=0, 22 to <24=1, 24 to <26=2, 26 to <28=3, >=28=4; mean CCT microns >=600=0, 576 to <600=1, 551 to <576=2, 526 to <551=3, <=525=4; mean vertical cup-disc ratio <0.3=0, 0.3 to <0.4=1, 0.4 to <0.5=2, 0.5 to <0.6=3, >=0.6=4; mean Humphrey PSD dB <1.8=0, 1.8 to <2.0=1, 2 to <2.4=2, 2.4 to <2.8=3, >=2.8=4; sum 0-6 -> 4.0% (<=4.0%), 7-8 -> 10%, 9-10 -> 15%, 11-12 -> 20%, >12 -> 33% (>=33%); no race; no diabetes; not a glaucoma diagnosis
```

## Citation

[A validated prediction model for the development of primary open-angle glaucoma in individuals with ocular hypertension](https://doi.org/10.1016/j.ophtha.2006.08.031)
Ocular Hypertension Treatment Study Group; European Glaucoma Prevention Study Group; Gordon MO, Torri V, Miglior S, Beiser JA, Floriani I, Miller JP, Gao F, Adamsons I, Poli D, D'Agostino RB, Kass MA
Ophthalmology. 2007;114(1):10-19
DOI: [10.1016/j.ophtha.2006.08.031](https://doi.org/10.1016/j.ophtha.2006.08.031)

## Worked example

### Paper Table 6 example: age 55, mean IOP 24 (22 and 26), mean CCT 540 (532 and 548), C/D 0.4, PSD 2.2 dB

Given: `age=55, cct_microns=540, iop_mm_hg=24, psd_db=2.2, vertical_cd_ratio=0.4`

1. Paper averages the two eyes: IOP (22+26)/2 = 24; CCT (532+548)/2 = 540; C/D 0.4; PSD 2.2
2. Age 55 -> 2; IOP 24 -> 2; CCT 540 -> 3; C/D 0.4 -> 2; PSD 2.2 -> 2
3. Sum of points = 11 -> Table 6 estimated 5-year POAG risk 20.0%


### Same predictors with mean IOP 28 mm Hg

Given: `age=55, cct_microns=540, iop_mm_hg=28, psd_db=2.2, vertical_cd_ratio=0.4`

1. IOP 28 is the Table 6 >=28 band (4 points instead of 2)
2. points 13; risk_5y_percent 33.0


## Also searched as

- OHTS-EGPS
- ocular hypertension glaucoma risk
- 5-year POAG risk
- Gordon 2007 glaucoma
- central corneal thickness glaucoma
- pattern standard deviation POAG
- OHTS risk points

## Parameters

- `age` (integer, required): Age in years (integer 30-80). OHTS enrolled 40-80; EGPS enrolled age >30. magent accepts 30-80 only. Table 6: <45=0, 45 to <55=1, 55 to <65=2, 65 to <75=3, >=75=4.
- `iop_mm_hg` (number, required): Mean untreated intraocular pressure in mm Hg (20-32), average of the two eyes after multiple Goldmann readings as in the paper. Table 6: <22=0, 22 to <24=1, 24 to <26=2, 26 to <28=3, >=28=4. magent does not measure IOP.
- `cct_microns` (number, required): Mean central corneal thickness in microns (475-650), average of the two eyes. Table 6: >=600=0, 576 to <600=1, 551 to <576=2, 526 to <551=3, <=525=4. magent does not perform pachymetry.
- `vertical_cd_ratio` (number, required): Mean vertical cup-disc ratio by contour (0-1), average of the two eyes. Table 6: <0.3=0, 0.3 to <0.4=1, 0.4 to <0.5=2, 0.5 to <0.6=3, >=0.6=4. magent does not grade the disc.
- `psd_db` (number, required): Mean Humphrey pattern standard deviation in dB (0.5-8), average of the two eyes. Table 6: <1.8=0, 1.8 to <2.0=1, 2 to <2.4=2, 2.4 to <2.8=3, >=2.8=4. magent does not run perimetry.

## Bulk (POST)

POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement.

Method: `POST /api/calc/ohts`
Max items: 25
Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic)
Status: PREVIEW

- 1 to 25 items. Each item uses the same keys as the GET query parameters.
- POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows.
- The first invalid item fails the whole request (index in the 400 JSON). You are not charged.
- HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row.
- Catalog misses (empty matches, found=false) stay paid 200s inside that slot.
- x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items.

Example request:

```json
{
  "items": [
    {
      "age": "55",
      "cct_microns": "540",
      "iop_mm_hg": "24",
      "psd_db": "2.2",
      "vertical_cd_ratio": "0.4"
    },
    {
      "age": "55",
      "cct_microns": "540",
      "iop_mm_hg": "24",
      "psd_db": "2.2",
      "vertical_cd_ratio": "0.4"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/ohts

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/ohts",
  "items": [
    {
      "points": 11,
      "age": 55,
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "citation": {
        "authors": "Ocular Hypertension Treatment Study Group; European Glaucoma Prevention Study Group; Gordon MO, Torri V, Miglior S, Beiser JA, Floriani I, Miller JP, Gao F, Adamsons I, Poli D, D'Agostino RB, Kass MA",
        "doi": "10.1016/j.ophtha.2006.08.031",
        "id": "ohts-egps-2007",
        "pmid": "17070597",
        "source": "Ophthalmology. 2007;114(1):10-19",
        "title": "A validated prediction model for the development of primary open-angle glaucoma in individuals with ocular hypertension"
      },
      "formula": "ohts",
      "formula_expression": "OHTS-EGPS 2007 Table 6 points: age <45=0, 45 to <55=1, 55 to <65=2, 65 to <75=3, >=75=4; mean IOP mm Hg <22=0, 22 to <24=1, 24 to <26=2, 26 to <28=3, >=28=4; mean CCT microns >=600=0, 576 to <600=1, 551 to <576=2, 526 to <551=3, <=525=4; mean vertical cup-disc ratio <0.3=0, 0.3 to <0.4=1, 0.4 to <0.5=2, 0.5 to <0.6=3, >=0.6=4; mean Humphrey PSD dB <1.8=0, 1.8 to <2.0=1, 2 to <2.4=2, 2.4 to <2.8=3, >=2.8=4; sum 0-6 -> 4.0% (<=4.0%), 7-8 -> 10%, 9-10 -> 15%, 11-12 -> 20%, >12 -> 33% (>=33%); no race; no diabetes; not a glaucoma diagnosis",
      "cct_microns": 540.0,
      "iop_mm_hg": 24.0,
      "psd_db": 2.2,
      "risk_5y_percent": 20.0,
      "vertical_cd_ratio": 0.4
    },
    {
      "points": 11,
      "age": 55,
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "citation": {
        "authors": "Ocular Hypertension Treatment Study Group; European Glaucoma Prevention Study Group; Gordon MO, Torri V, Miglior S, Beiser JA, Floriani I, Miller JP, Gao F, Adamsons I, Poli D, D'Agostino RB, Kass MA",
        "doi": "10.1016/j.ophtha.2006.08.031",
        "id": "ohts-egps-2007",
        "pmid": "17070597",
        "source": "Ophthalmology. 2007;114(1):10-19",
        "title": "A validated prediction model for the development of primary open-angle glaucoma in individuals with ocular hypertension"
      },
      "formula": "ohts",
      "formula_expression": "OHTS-EGPS 2007 Table 6 points: age <45=0, 45 to <55=1, 55 to <65=2, 65 to <75=3, >=75=4; mean IOP mm Hg <22=0, 22 to <24=1, 24 to <26=2, 26 to <28=3, >=28=4; mean CCT microns >=600=0, 576 to <600=1, 551 to <576=2, 526 to <551=3, <=525=4; mean vertical cup-disc ratio <0.3=0, 0.3 to <0.4=1, 0.4 to <0.5=2, 0.5 to <0.6=3, >=0.6=4; mean Humphrey PSD dB <1.8=0, 1.8 to <2.0=1, 2 to <2.4=2, 2.4 to <2.8=3, >=2.8=4; sum 0-6 -> 4.0% (<=4.0%), 7-8 -> 10%, 9-10 -> 15%, 11-12 -> 20%, >12 -> 33% (>=33%); no race; no diabetes; not a glaucoma diagnosis",
      "cct_microns": 540.0,
      "iop_mm_hg": 24.0,
      "psd_db": 2.2,
      "risk_5y_percent": 20.0,
      "vertical_cd_ratio": 0.4
    }
  ]
}
```

## Response fields

- `formula` (string): ohts
- `formula_expression` (string): OHTS-EGPS 2007 Table 6 point bands and mapped 5-year percents
- `age` (integer): Age in years used (30-80)
- `iop_mm_hg` (number): Mean IOP used, mm Hg
- `cct_microns` (number): Mean CCT used, microns
- `vertical_cd_ratio` (number): Mean vertical cup-disc ratio used
- `psd_db` (number): Mean Humphrey PSD used, dB
- `points` (integer): Table 6 point total
- `risk_5y_percent` (number): Mapped 5-year POAG percent from the Table 6 sum (4.0, 10, 15, 20, or 33)
- `citation` (object): OHTS-EGPS Ophthalmology 2007 citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "points": 11,
  "age": 55,
  "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "citation": {
    "authors": "Ocular Hypertension Treatment Study Group; European Glaucoma Prevention Study Group; Gordon MO, Torri V, Miglior S, Beiser JA, Floriani I, Miller JP, Gao F, Adamsons I, Poli D, D'Agostino RB, Kass MA",
    "doi": "10.1016/j.ophtha.2006.08.031",
    "id": "ohts-egps-2007",
    "pmid": "17070597",
    "source": "Ophthalmology. 2007;114(1):10-19",
    "title": "A validated prediction model for the development of primary open-angle glaucoma in individuals with ocular hypertension"
  },
  "formula": "ohts",
  "formula_expression": "OHTS-EGPS 2007 Table 6 points: age <45=0, 45 to <55=1, 55 to <65=2, 65 to <75=3, >=75=4; mean IOP mm Hg <22=0, 22 to <24=1, 24 to <26=2, 26 to <28=3, >=28=4; mean CCT microns >=600=0, 576 to <600=1, 551 to <576=2, 526 to <551=3, <=525=4; mean vertical cup-disc ratio <0.3=0, 0.3 to <0.4=1, 0.4 to <0.5=2, 0.5 to <0.6=3, >=0.6=4; mean Humphrey PSD dB <1.8=0, 1.8 to <2.0=1, 2 to <2.4=2, 2.4 to <2.8=3, >=2.8=4; sum 0-6 -> 4.0% (<=4.0%), 7-8 -> 10%, 9-10 -> 15%, 11-12 -> 20%, >12 -> 33% (>=33%); no race; no diabetes; not a glaucoma diagnosis",
  "cct_microns": 540.0,
  "iop_mm_hg": 24.0,
  "psd_db": 2.2,
  "risk_5y_percent": 20.0,
  "vertical_cd_ratio": 0.4
}
```

## Errors

- HTTP 400 `invalid_age`: age must be an integer from 18 to 120 Returned before settlement; you are not charged.
- HTTP 400 `invalid_ohts`: OHTS-EGPS 2007 inputs must match that paper's age, IOP, central corneal thickness, vertical cup-disc ratio, and pattern standard deviation. Returned before settlement; you are not charged.
- HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
- HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
- HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged.

Shared HTTP 402 and 503: https://magentlab.com/docs/payments

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## Payment

Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s.

- GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall).
- HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote.
- Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering.
- Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional.
- Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402.

- offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront.
- offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization.

- not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search.

Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers).

Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments

Stdio MCP (one process per host): https://magentlab.com/docs/mcp

## Guarantees

- HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. HTTP 402 never includes the tool JSON.
- exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE.
- HTTP 402 is unpaid only. Do not sign a second authorization because of a 503.
- Execution is timeout-bounded and concurrency-capped.
- Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.