define "Initial Population":
  AgeInYearsAt(date from start of "Measurement Period") >= 18
    and exists "Primary Open Angle Glaucoma Encounter"

define "Denominator":
  "Initial Population"

define "Numerator":
  exists "Cup to Disc Ratio Performed with Result"
    and exists "Optic Disc Exam Performed with Result"

define "Denominator Exceptions":
  exists "Medical Reason for Not Performing Cup to Disc Ratio"
    or exists "Medical Reason for Not Performing Optic Disc Exam"

define "SDE Sex":
  case
    when Patient.sex = '248153007' then "Male (finding)"
    when Patient.sex = '248152002' then "Female (finding)"
    else null
  end

define "SDE Payer":
  [Coverage: type in "Payer Type"] Payer
    return {
      code: Payer.type,
      period: Payer.period
    }

define "SDE Ethnicity":
  Patient.ethnicity E
    return Tuple {
      codes: { E.ombCategory } union E.detailed,
      display: E.text
    }

define "SDE Race":
  Patient.race R
    return Tuple {
      codes: R.ombCategory union R.detailed,
      display: R.text
    }

define "SDE Sex":
  SDE."SDE Sex"

define "Qualifying Encounter During Measurement Period":
  ( ["Encounter": "Office Visit"]
    union ["Encounter": "Ophthalmological Services"]
    union ["Encounter": "Outpatient Consultation"]
    union ["Encounter": "Nursing Facility Visit"]
    union ["Encounter": "Care Services in Long-Term Residential Facility"] ) QualifyingEncounter
    where QualifyingEncounter.period during day of "Measurement Period"
      and QualifyingEncounter.status = 'finished'
      and QualifyingEncounter.class !~ "virtual"

define "Primary Open Angle Glaucoma Encounter":
  "Qualifying Encounter During Measurement Period" ValidQualifyingEncounter
    with ( ["ConditionProblemsHealthConcerns": "Primary Open-Angle Glaucoma"]
      union ["ConditionEncounterDiagnosis": "Primary Open-Angle Glaucoma"] ) PrimaryOpenAngleGlaucoma
      such that PrimaryOpenAngleGlaucoma.prevalenceInterval ( ) overlaps day of ValidQualifyingEncounter.period
        and PrimaryOpenAngleGlaucoma.isVerified ( )

define "Cup to Disc Ratio Performed with Result":
  ["ObservationClinicalResult": "Cup to Disc Ratio"] CupToDiscExamPerformed
    with "Primary Open Angle Glaucoma Encounter" EncounterWithPOAG
      such that CupToDiscExamPerformed.effective.toInterval ( ) during day of EncounterWithPOAG.period
    where CupToDiscExamPerformed.value is not null
      and CupToDiscExamPerformed.status in { 'final', 'amended', 'corrected' }

define "Optic Disc Exam Performed with Result":
  ["ObservationClinicalResult": "Optic Disc Exam for Structural Abnormalities"] OpticDiscExamPerformed
    with "Primary Open Angle Glaucoma Encounter" EncounterWithPOAG
      such that OpticDiscExamPerformed.effective.toInterval ( ) during day of EncounterWithPOAG.period
    where OpticDiscExamPerformed.value is not null
      and OpticDiscExamPerformed.status in { 'final', 'amended', 'corrected' }

define "Numerator":
  exists "Cup to Disc Ratio Performed with Result"
    and exists "Optic Disc Exam Performed with Result"

define "Initial Population":
  AgeInYearsAt(date from start of "Measurement Period") >= 18
    and exists "Primary Open Angle Glaucoma Encounter"

define "Denominator":
  "Initial Population"

define "SDE Payer":
  SDE."SDE Payer"

define "SDE Ethnicity":
  SDE."SDE Ethnicity"

define "SDE Race":
  SDE."SDE Race"

define "Medical Reason for Not Performing Cup to Disc Ratio":
  ["ObservationCancelled": "Cup to Disc Ratio"] CupToDiscExamNotPerformed
    with "Primary Open Angle Glaucoma Encounter" EncounterWithPOAG
      such that CupToDiscExamNotPerformed.issued during day of EncounterWithPOAG.period
    where CupToDiscExamNotPerformed.notDoneReason in "Medical Reason"

define "Medical Reason for Not Performing Optic Disc Exam":
  ["ObservationCancelled": "Optic Disc Exam for Structural Abnormalities"] OpticDiscExamNotPerformed
    with "Primary Open Angle Glaucoma Encounter" EncounterWithPOAG
      such that OpticDiscExamNotPerformed.issued during day of EncounterWithPOAG.period
    where OpticDiscExamNotPerformed.notDoneReason in "Medical Reason"

define "Denominator Exceptions":
  exists "Medical Reason for Not Performing Cup to Disc Ratio"
    or exists "Medical Reason for Not Performing Optic Disc Exam"

define function ToString(value uri): value.value

/*
@description: Converts the given [Period](https://hl7.org/fhir/datatypes.html#Period)
value to a CQL DateTime Interval
@comment: If the start value of the given period is unspecified, the starting
boundary of the resulting interval will be open (meaning the start of the interval
is unknown, as opposed to interpreted as the beginning of time).
*/
define function ToInterval(period FHIR.Period):
    if period is null then
        null
    else
        if period."start" is null then
            Interval(period."start".value, period."end".value]
        else
            Interval[period."start".value, period."end".value]

/*
@description: Converts the given FHIR [Coding](https://hl7.org/fhir/datatypes.html#Coding) value to a CQL Code.
*/
define function ToCode(coding FHIR.Coding):
    if coding is null then
        null
    else
        System.Code {
          code: coding.code.value,
          system: coding.system.value,
          version: coding.version.value,
          display: coding.display.value
        }