<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="DhdCataractVisus" />
  <url value="http://dhd.nl/fhir/StructureDefinition/DhdCataractVisus" />
  <version value="0.1.1" />
  <name value="DhdCataractVisus" />
  <status value="draft" />
  <description value="Visus measurement as defined in proposed ZIB for Visus." />
  <fhirVersion value="3.0.2" />
  <kind value="resource" />
  <abstract value="false" />
  <type value="Observation" />
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Observation" />
  <derivation value="constraint" />
  <snapshot />
  <differential>
    <element id="Observation.category">
      <path value="Observation.category" />
      <definition value="onderzoek van gezichtsscherpte (verrichting)" />
    </element>
    <element id="Observation.category.coding.system">
      <path value="Observation.category.coding.system" />
      <fixedUri value="http://snomed.info/sct" />
    </element>
    <element id="Observation.category.coding.code">
      <path value="Observation.category.coding.code" />
      <fixedCode value="16830007" />
    </element>
    <element id="Observation.code">
      <path value="Observation.code" />
      <definition value="Visual acuity (observable entity)" />
    </element>
    <element id="Observation.code.coding.system">
      <path value="Observation.code.coding.system" />
      <fixedUri value="http://snomed.info/sct" />
    </element>
    <element id="Observation.code.coding.code">
      <path value="Observation.code.coding.code" />
      <fixedCode value="363983007" />
    </element>
    <element id="Observation.subject">
      <path value="Observation.subject" />
      <min value="1" />
      <type>
        <code value="Reference" />
        <targetProfile value="http://dhd.nl/fhir/StructureDefinition/DhdCataractPatient" />
      </type>
    </element>
    <element id="Observation.effective[x]:effectiveDateTime">
      <path value="Observation.effectiveDateTime" />
      <sliceName value="effectiveDateTime" />
      <min value="1" />
      <type>
        <code value="dateTime" />
      </type>
    </element>
    <element id="Observation.value[x]:valueQuantity">
      <path value="Observation.valueQuantity" />
      <sliceName value="valueQuantity" />
      <type>
        <code value="Quantity" />
      </type>
      <condition value="visus-quantity" />
      <constraint>
        <key value="visus-quantity" />
        <severity value="error" />
        <human value="Visus quantity outside range (0 - 2.00) (actually &lt;= 3.00 as NOG wants to make sure that slightly larger visus also will be incorporated.)" />
        <expression value="$this.as(Quantity).value &gt;=0 and $this.as(Quantity).value &lt;= 3.00" />
      </constraint>
    </element>
    <element id="Observation.bodySite">
      <path value="Observation.bodySite" />
      <min value="1" />
    </element>
    <element id="Observation.bodySite.extension">
      <path value="Observation.bodySite.extension" />
      <slicing>
        <discriminator>
          <type value="value" />
          <path value="url" />
        </discriminator>
        <rules value="open" />
      </slicing>
    </element>
    <element id="Observation.bodySite.extension:VisusLaterality">
      <path value="Observation.bodySite.extension" />
      <sliceName value="VisusLaterality" />
      <min value="1" />
      <max value="1" />
      <type>
        <code value="Extension" />
        <profile value="http://nictiz.nl/fhir/StructureDefinition/BodySite-Qualifier" />
      </type>
    </element>
    <element id="Observation.bodySite.extension:VisusLaterality.valueCodeableConcept:valueCodeableConcept">
      <path value="Observation.bodySite.extension.valueCodeableConcept" />
      <sliceName value="valueCodeableConcept" />
      <binding>
        <strength value="extensible" />
        <description value="VisusLateralityCodelist" />
        <valueSetUri value="http://dhd.nl/fhir/ValueSet/VisusLateraliteitCodelijst" />
      </binding>
    </element>
    <element id="Observation.method.coding">
      <path value="Observation.method.coding" />
      <binding>
        <strength value="extensible" />
        <description value="VisusMetingTypeCodelijst" />
        <valueSetUri value="http://dhd.nl/fhir/ValueSet/VisusMetingTypeCodelijst" />
      </binding>
    </element>
  </differential>
</StructureDefinition>