Overview
ISO/TS 22218-2:2023 defines standardized data output formats for specular microscopes used in ophthalmic practice. The Technical Specification specifies how text-based analysis results (for example, central corneal thickness, endothelial cell density per mm², coefficient of variation, and hexagonality) are formatted and exchanged from devices to higher-level systems such as an Ophthalmic Information System (OIS) or a Hospital Information System (HIS). The specification aligns device output with the Ophthalmic Examination Device Data (OEDD) model and is compliant with CDA® Release 2 syntax.
Key topics and technical requirements
- Data types and measurements: Standardized reporting of corneal endothelium metrics - central corneal thickness, endothelial cell density (cells/mm²), coefficient of variation (CV), and hexagonality (HEX).
- deviceCDA concept: Defines a strict subset of CDA (deviceCDA) to allow devices to send examination data without full patient/operator metadata; the OIS enriches and converts this into a complete CDA for HIS submission.
- OEDD structure and XML schema: Layouts for embedding SPECULAR data in a CDA XML file, including support for combining multiple device types (SPECULAR, REF, KM, TM, LM, PHOR) in one document.
- Data classification and codes: Use of coded section attributes (e.g., LOINC-style codes such as 100066-0 for SPECULAR) to identify device data types and enable consistent parsing.
- Handling common data and units: Guidance on common header elements, unit handling, and how to ignore unrecognized/private extensions to maintain interoperability.
- Supporting materials: Annexes include use cases (Annex A), standard codes for common and ophthalmic data (Annices B and C), sample XML files (Annex D), and a bibliography.
Applications and who should use it
- Device manufacturers of specular microscopes - to produce interoperable, standardized data output.
- OIS and HIS vendors / integrators - to import, normalize and persist specular microscope results and produce CDA-compliant reports.
- Hospital IT and clinical engineers - to implement workflows that integrate corneal endothelial metrics into electronic medical records.
- Clinical teams (ophthalmologists, optometrists) - benefit indirectly through reliable data exchange supporting diagnosis (dry eye, Fuchs’ dystrophy, bullous keratopathy), monitoring and contact lens fitting.
- Regulatory and standards teams - for compliance and device-to-system interoperability planning.
Related standards
- ISO/TS 22218-1 (series context)
- HL7 CDA® Release 2 (syntax compliance)
- LOINC (for laboratory/measurement coding)
Keywords: ISO/TS 22218-2:2023, specular microscope, health informatics, ophthalmic examination device data, deviceCDA, OIS, HIS, endothelial cell density, corneal thickness, OEDD, CDA R2, XML schema, interoperability.