ISO/TS 22218-2:2023
(Main)Health informatics — Ophthalmic examination device data — Part 2: Specular microscope
Health informatics — Ophthalmic examination device data — Part 2: Specular microscope
This document specifies the data output formats for the specular microscope. The data are usually sent from the specular microscope to either an ophthalmic information system (OIS) or a hospital information system (HIS). This document addresses text-based analysis reporting of the specular microscope measured and analysed data such as the central corneal thickness, the density of endothelial cells per 1 mm2, the coefficient variant, and the ratio of endothelial cells with a hexagonal shape.
Informatique de santé — Données relatives aux dispositifs d'examen ophtalmique — Partie 2: Microscope spéculaire
General Information
Standards Content (Sample)
TECHNICAL ISO/TS
SPECIFICATION 22218-2
First edition
2023-01
Health informatics — Ophthalmic
examination device data —
Part 2:
Specular microscope
Informatique de santé — Données relatives aux dispositifs d'examen
ophtalmique —
Partie 2: Microscope spéculaire
Reference number
ISO/TS 22218-2:2023(E)
© ISO 2023
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ISO/TS 22218-2:2023(E)
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ISO/TS 22218-2:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Specifications . 3
4.1 General . 3
4.2 deviceCDA and persistent examination reports . 3
4.3 Data classification constitution in the file . 4
4.4 OEDD structure . 5
4.4.1 General . 5
4.4.2 Data classifications . 5
4.4.3 Attribute value and classification . 5
4.4.4 Handling of common data . 6
4.4.5 Handling of ophthalmic examination data . 8
4.4.6 Handling of units of measurement . 9
4.5 OEDD XML schema . 9
Annex A (informative) Use cases of specular microscope .11
Annex B (informative) Standard codes used for common data .13
Annex C (informative) Standard codes for ophthalmic examination data .14
Annex D (informative) Sample files .19
Bibliography .35
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ISO/TS 22218-2:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 215, Health informatics.
A list of all parts in the ISO 22218 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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ISO/TS 22218-2:2023(E)
Introduction
Ophthalmic devices are used in hospitals and clinics to examine patients. The primary devices used in
these ophthalmic examinations provide the measurement of refraction, corneal curvature, intraocular
pressure, lens power, and visual acuity. Almost all patients who consult for a diagnosis in ophthalmology
undergo these examinations.
Besides such general ophthalmic devices, specular microscopes are often used to capture and analyze
an image of the corneal endothelium, which dehydrates the corneal stroma and maintains the cornea’s
clarity. Thus, measuring the cell density of the corneal endothelium is one of the most crucial and reliable
methods to determine its condition. The analysis results of the specular microscope are indispensable
for not only patients experiencing trouble in the cornea but also safe prescriptions for contact lenses.
Like other ophthalmic devices, various manufacturers supply specular microscopes. Thus, standardized
procedures for mutually communicating analysis results are crucial between the specular microscope
and ophthalmic information system (OIS).
However, the integration of this information is complex and potentially error-prone owing to variable
data formats provided by specular microscopes from different manufacturers and the lack of
interoperability. Thus, the integration of analysis results from various specular microscopes into an
OIS or hospital information system (HIS) warrants significant individual effort for each manufacturer’s
specular microscope.
This document specifies the content and format for the analysis results of specular microscopes,
identifying the information that could be included in the analysis results, as well as how it should be
formatted when communicated to an OIS, HIS, or other similar systems.
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TECHNICAL SPECIFICATION ISO/TS 22218-2:2023(E)
Health informatics — Ophthalmic examination device
data —
Part 2:
Specular microscope
1 Scope
This document specifies the data output formats for the specular microscope. The data are usually
sent from the specular microscope to either an ophthalmic information system (OIS) or a hospital
information system (HIS).
This document addresses text-based analysis reporting of the specular microscope measured and
2
analysed data such as the central corneal thickness, the density of endothelial cells per 1 mm , the
coefficient variant, and the ratio of endothelial cells with a hexagonal shape.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
corneal endothelium
monolayer of endothelial cells that constitutes the posterior corneal surface
Note 1 to entry: The corneal endothelium dehydrates the corneal stroma and maintains the cornea’s clarity.
Note 2 to entry: Measuring the endothelial cell density provides valuable information about the cornea’s
condition.
3.2
endothelial cell density
CD
2
number indicating how many endothelial cells are present in one square millimeter (mm )
Note 1 to entry: This value is often referenced to determine the condition of the corneal endothelium. If the
corneal endothelium is young and healthy, the value is high, and if the corneal endothelium is old and damaged,
the value is low.
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ISO/TS 22218-2:2023(E)
3.3
coefficient of variation
CV
ratio of the standard deviation to the mean in cell size, which is standardized measure of the dispersion
of the size of each endothelial cell
Note 1 to entry: This value is often referenced to determine the condition of the corneal endothelium, owing to
uniform cell size, healthy corneal endothelium has a small CV value.
3.4
hexagonality
HEX
morphology of endothelial cells, usually the percentage of hexagonal cells
Note 1 to entry: This value is often referenced to determine the condition of the corneal endothelium. Cells of
healthy corneal endothelium have uniform size and are primarily hexagonal.
3.5
dry eye
disease in which the stability of the tear film is reduced
3.6
Fuchs’ dystrophy
slowly progressing corneal dystrophy in which fluid builds up and the cornea gets swollen and puffy
3.7
bullous keratopathy
eye disorder due to oedema that involves a swelling of the cornea
3.8
ophthalmic information system
OIS
computer system that acquires, stores, retrieves and manages ophthalmic images and examination data
Note 1 to entry: The OIS gather and manage examination information from various ophthalmic devices and
submit persistent examination reports in CDA RMIM format to HIS.
[SOURCE: ISO/TS 22218-1:2022, 3.19]
3.9
deviceCDA
subset of the CDA RMIM dataset that only includes the information contained in a device
Note 1 to entry: Most ophthalmic examination devices do not support all the mandatory information required by
a complete CDA document, such as patient or operator identification, and additional information can be accessed
after the report is sent to an OIS or HIS.
[SOURCE: ISO/TS 22218-1:2022, 3.20]
3.10
hospital information system
HIS
comprehensive, integrated information system designed to manage all the aspects of a hospital's
operation
Note 1 to entry: In many implementations, a HIS covers hospital's operation such as medical, administrative,
financial, and legal issues and the corresponding processing of services.
[6]
[SOURCE: IS4H-MM ]
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ISO/TS 22218-2:2023(E)
4 Specifications
4.1 General
OEDD provides standards both for transferring clinical ophthalmic examination data from various
types of examination devices to an OIS, as well as submitting persistent reports based on those
examination data from an OIS to a HIS. The specular microscope is one such examination device.
Exemplary use cases are detailed in Annex A.
It is possible to handle multiple data types such as SPECULAR (Specular microscope), REF
(Refractometer), KM (Keratometer), TM (Tonometer), LM (Lensmeter), and PHOR (Phoroptor) within
one XML file. It is acceptable to compile SPECULAR, REF, KM, TM, LM, and PHOR in one file or separate
them into different files. Within the file, is the top tag in accordance with the rules
for CDA.
REF (Refractometer), KM (Keratometer), TM (Tonometer), LM (Lensmeter), and PHOR (Phoroptor) are
also ophthalmic examination devices described in this document.
For details, see 4.3.
The standard codes used in this document are shown in Annex C, and a sample XML file is shown in
Annex D.
4.2 deviceCDA and persistent examination reports
Most OEDD devices only output examination data and related information, and cannot provide
additional data items such as Patient, Operator, Custodian, and Authentication.
For such devices, OEDD introduces deviceCDA, a strict subset of CDA, that allows devices to transfer
examination data and related information as a deviceCDA dataset without the additional detailed
patient identification information that is required in complete CDA documents.
OIS plays the role of receiving examination data and related information as a deviceCDA dataset from
a device and then submitting a persistent examination report to a HIS with additional information
required for the complete CDA dataset.
deviceCDA is not a complete CDA dataset but still conforms to the same syntax. OIS, therefore, prepares
a complete OEDD that includes the CDA RMIM dataset with information such as Patient, Operator,
Custodian, and Authentication, and inserts the deviceCDA dataset received from the device into the
OEDD. (See Figure 1)
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ISO/TS 22218-2:2023(E)
Figure 1 — Concept of a deviceCDA
4.3 Data classification constitution in the file
Both a deviceCDA and a complete CDA file has and as
the top tag.
It is possible to collect information from all the OEDD classifications into one file, or they can be separated
into different deviceCDA/Complete CDA files. In the case of a single composite OEDD deviceCDA/
Complete CDA document, the data tags that are common across the devices shall be specified once, and
the OEDD data tags integrated separately. Table 1 shows some examples of such deviceCDA File data
block layouts. Data tags of REF, KM, RM, LM, and PHOR are stored in the file together with SPECULAR.
Implementations may encounter data classifications that are not included in the OEDD specification (e.g.
private extensions), in which case, implementations shall ignore non-recognized data classifications
and process the known data classifications accordingly.
Table 1 — Example deviceCDA file data block layouts
Common Data Common Data Common Data Common Data
SPECULAR Data SPECULAR Data SPECULAR Data TM Data
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ISO/TS 22218-2:2023(E)
TTabablele 1 1 ((ccoonnttiinnueuedd))
TM Data REF Data KR Data
TM Data SPECULAR Data
LM Data PHOR Data
File 1 File 2 File 3 File 4
4.4 OEDD structure
4.4.1 General
This specification is compliant with CDA-R2. For this reason, the complete detailed file structure can be
[6]
reviewed in HL7 CDA® Release 2 .
In this document, only descriptions particular to ophthalmology are included.
4.4.2 Data classifications
The data classifications of refractometer, keratometer, tonometer, and such are maintained as attribute
value (type) of tags.
4.4.3 Attribute value and classification
Table 2 shows ophthalmic examination device data classification values.
Table 2 — OEDD device classification values
Attribute value (code) Data classification
100066-0 Specular microscope data
1)
Figure 2 shows the example of specular microscope data (SPECULAR) that uses a LOINC® code.
1) LOINC is the registered trademark of Regenstrief Institute. This information is given for the convenience of
users of this document and does not constitute an endorsement by ISO of the product named.
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ISO/TS 22218-2:2023(E)
Figure 2 — OEDD section tags
4.4.4 Handling of common data
4.4.4.1 General
Common data such as ophthalmic examination title are described in the CDA Header part between the
tag and < structuredBody>. This common data will be present only once in a file.
4.4.4.2 Common data tags
Table 3 shows available Common data tags.
Table 3 — Common data tags
a
Tag name Description Necessity
ClinicalDocument CDA-R2 D
Type ID. The compliant D
typeId CDA R2 specifications are
identified.
ID for unique identifica- D
id tion specified at hospitals,
etc. or groups
A code that represents the D
code
reporting category
Ex) Ophthalmic exami- D
title
nations
Date & time of the creation C
effectiveTime of the file (yyyymmddh-
hmmss)
Confidentiality level code. D
The confidentiality value
in the HL7 vocabulary do-
confidentialityCode
main is used
Ex) code="N"
languageCode D
languageCode
Ex) code="jpn"
versionNumber Document version number D
recordTarget Patient D
patientRole Patient information D
a
The items in the Necessity column have the following meanings:
D - Tags and values are necessary for both Complete CDA and deviceCDA
C - Tags and values are necessary for Complete CDA
O - No tags or values are necessary
b
Multiple settings are allowed for Patient No. Also, nullFlavor="NI" is allowed.
c
Multiple settings are allowed for the Patient names. If First name and Last name cannot be separated, the Last name
should be entered in the First name section. Also, nullFlavor="NI" is allowed.
d
Refer to "Annex B".
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ISO/TS 22218-2:2023(E)
TTabablele 3 3 ((ccoonnttiinnueuedd))
a
Tag name Description Necessity
Patient No. D
(number of the order of
id b
examination)
Ex) extension="123456"
c
patient Patient name C
c
name Alphabetic expression C
c
family family name C
c
given Given name C
Regional ideographic or O
name
c
phonetic name
c
family family name O
c
given Given name O
Patient's sex C
administrativeGenderCode
d
EX) F/M/UN
Patient’s date of birth C
birthTime
(yyyymmdd)
author Author D
Date & time of the creation D
time
(yyyymmddhhmmss)
Information of the organ- D
assignedAuthor ization that prepares the
document.
Assigned author ID D
id
"NI": If id is none
assignedAuthoringDevice Assigned authoring device D
Model name and No. for D
manufacturerModelName distinction among the
devices of the same model
softwareName Software and ROM version D
representedOrganization Represented organization C
Represented organiza- C
tion ID
id
"NI": If id is none
name Company name C
custodian custodian C
assignedCustodian Assigned custodian C
Represented custodian C
representedCustodianOrganization
organization
a
The items in the Necessity column have the following meanings:
D - Tags and values are necessary for both Complete CDA and deviceCDA
C - Tags and values are necessary for Complete CDA
O - No tags or values are necessary
b
Multiple settings are allowed for Patient No. Also, nullFlavor="NI" is allowed.
c
Multiple settings are allowed for the Patient names. If First name and Last name cannot be separated, the Last name
should be entered in the First name section. Also, nullFlavor="NI" is allowed.
d
Refer to "Annex B".
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ISO/TS 22218-2:2023(E)
TTabablele 3 3 ((ccoonnttiinnueuedd))
a
Tag name Description Necessity
Represented custodian C
organization ID
id
"NI": If id is none
documentationOf Operator C
serviceEvent code C
serviceEvent
EX) classCode="ACSN"
code serviceEvent code C
performer type code C
performer
EX) typeCode="PRF"
Function code C
functionCode
d
EX) code="SNRS"
assignedEntity assignedEntity C
id Operator ID C
a
The items in the Necessity column have the following meanings:
D - Tags and values are necessary for both Complete CDA and deviceCDA
C - Tags and values are necessary for Complete CDA
O - No tags or values are necessary
b
Multiple settings are allowed for Patient No. Also, nullFlavor="NI" is allowed.
c
Multiple settings are allowed for the Patient names. If First name and Last name cannot be separated, the Last name
should be entered in the First name section. Also, nullFlavor="NI" is allowed.
d
Refer to "Annex B".
4.4.5 Handling of ophthalmic examination data
4.4.5.1 General
Examination data are described in the section of the deviceCDA as follows:
---(Refer to 4.4.5.2 for detail content)
4.4.5.2 Ophthalmic examination data tags
Table 4 shows basic composition of tags used for ophthalmic examination data:
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ISO/TS 22218-2:2023(E)
Table 4 — Ophthalmic examination data tags
a
Tag name Description Necessity
component CDA-R2 component D
structuredBody D
Examination tag defined here -
Component CDA-R2 component D
section section D
LOINC's Exam Details Code D
code
EX) Set code of LOINC for SPECULAR: "100066-
0"
examination title D
title
(HTML format)
text detail of examination D
entry D
Ex) classCode="OBS" moodCode="EVN" D
observation
(OBS=observation, EVN=examination results)
Examination code D
code
Ex) Magnification= "100067-8"
Date & time of the creation of the file (yyyym- D
effectiveTime
mddhhmmss)
entry D
Ex) classCode="OBS" moodCode="EVN" D
observation
(OBS=observation, EVN=examination results)
entryRelationship Detailed examination data D
Ex) classCode="OBS" moodCode="EVN" D
observation
(OBS=observation, EVN=examination results)
Examination code D
code
Ex) Cell Density Right= "100070-2"
b
value examination data & unit D
Ex) ID=”IMAGE1” classCode="OBS" mood- D
observationMedia
Code="EVN"
value Ex) mediaType="image/png" D
Ex) value="01_20150702_123821_A_R_EN- D
reference
HANCE.png
a
The items in the Necessity column have the following meanings:
D - Tags and values are necessary for both Complete CDA and deviceCDA.
O - No tags or values are necessary
b
Refer to Annex C for detail of examination data measured by each ophthalmic examination device.
4.4.6 Handling of units of measurement
The unit of measurement for numerical data is described as attribute value "unit".
2
ex)
4.5 OEDD XML schema
To comply with CDA-R2, CDA.XSD is designated as XML Schema.
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ISO/TS 22218-2:2023(E)
Ex) At the tag, it is designated as an attribute as follows.
xmlns: xsi = "https:// www .w3 .org/ 2001/ XMLSchema -instance" xmlns="urn: hl7 -org: v3">
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ISO/TS 22218-2:2023(E)
Annex A
(informative)
Use cases of specular microscope
A.1 Outline of specular microscope
Specular microscopes are often used to capture and analyze an image of the corneal endothelium, which
dehydrates the corneal stroma and maintains the cornea’s clarity. Thus, measuring the cell density
of the corneal endothelium is one of the salient and reliable non-invasive methods used to determine
its condition. For observing corneal endothelial cells, specular microscopes have been introduced in
almost all ophthalmic clinics. The analysis results of the specular microscope are indispensable for
not only patients experiencing problems in the cornea but also anyone who holds contact lenses safety
prescriptions. An image is occasionally attached to analysis results as a reference. This however is not
for analysis purposes but for providing physicians with the idea that the detected boundary lines are
acceptable.
A.2 Avoid surgically induced damage
Corneal endothelial cells do not regenerate, and they decrease with age, Fuchs’ corneal dystrophy, and
2
surgery. When the average density of corneal endothelial cells is ≤1 000 cells/mm , homeostasis cannot
be maintained.
The analysis data of specular microscopes provide evidence for determining whether it is safe to
perform cataract surgery, which causes additional loss of endothelial cells. In addition, it is used as
a postoperative monitoring device for cataract surgery. Thus, the specular microscope is essential
for surgical planning to avoid complications such as postoperative corneal opacification. The corneal
endothelium damages due to dry eye, Fuchs’ dystrophy, and epithelial basement membrane dystrophy
before surgery can also decrease the potential for positive surgical outcomes.
Reportedly, Fuchs’ corneal endothelial dystrophy has a potential prevalence of approximately 5 % in
Europe and the United States. If it decreases further, it causes bullous keratopathy, which causes vision
loss and eye pain. To estimate the prognosis of surgery, evaluation is indispensable before and after
surgery, such as cataract surgery.
Another benefit of checking the corneal endothelium often is to decide a better suitable approach
for cataract surgery. Occasionally, a less traumatic approach, such as a new femtosecond-phaco with
reduced phaco energy, should be chosen rather than conventional cataract surgery.
A.3 Postoperative evaluation and follow-up
Bullous keratopathy, which develops owing to a decrease in corneal endothelial cells, is a major cause
of corneal transplantation. In recent years, corneal endothelial transplantation and the injection of
cultured corneal endothelial cells have also been performed.
To evaluate this therapeutic effect, it is necessary to compare data over a more extended period than
ever before. Besides, there will be an international evaluation of new treatments. Further demands are
for specular microscope data interoperability, persistence, and international standards.
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ISO/TS 22218-2:2023(E)
A.4 Safe use of contact lenses
Periodic checking of the corneal endotheli
...
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