Master UDI-DI for optical devices – timelines and labeling rules clarified by MDCG
From prescription lenses to contact lenses, optical medical devices are among the most commonly used in Europe. While their everyday use may seem routine, the regulatory mechanisms that ensure their traceability and safety are anything but simple. In its July 2025 position paper (MDCG 2025-7), the Medical Device Coordination Group outlines clear timelines for the implementation of the Master UDI-DI solution for highly individualized optical devices.
The aim of this system, established under Article 27 of the MDR and related delegated acts, is to streamline the identification of similar products by assigning a single identifier, known as the Master UDI-DI, rather than generating thousands of individual device identifiers.
Who is affected?
The new obligations apply to the following categories of medical devices:
- Contact lenses (Class IIa/IIb),
- Spectacle frames, spectacle lenses, and ready-to-wear reading spectacles (Class I).
For contact lenses, the assignment of a Master UDI-DI becomes mandatory as of 9 November 2026. For spectacle frames, lenses, and reading glasses, the implementation deadline is set for September 2028.
What needs to be done?
The rollout of the Master UDI-DI solution consists of three key phases:
- Identifier assignment – Manufacturers must assign a Master UDI-DI based on grouping devices with similar design parameters, following the rules established by designated UDI issuing entities.
- Labelling – Once the Master UDI-DI is assigned, it must be placed on the device label and all higher levels of packaging, in accordance with Article 27(4) of the MDR.
- Registration in EUDAMED – The Master UDI-DI must be registered in the UDI/Device registration module of EUDAMED. This obligation is closely linked to the timeline of UDI-DI assignment.
Importantly, the MDCG strongly encourages voluntary early assignment of Master UDI-DIs before the official deadlines. Doing so allows manufacturers to become familiar with the system and leverage EUDAMED’s functionalities in advance, avoiding last-minute implementation bottlenecks.
Integration with Post-Market Surveillance
Once the Vigilance and PMS modules of EUDAMED become mandatory (currently expected in Q3 2026), any assigned Master UDI-DI will also need to be used in incident and field safety corrective action reporting. This reflects the growing integration of UDI data into broader post-market safety and reporting systems under the MDR.
Next steps
The MDCG has announced plans to publish additional guidance documents, including an updated MDCG 2024-14 for contact lenses and a new MDCG 2025-XX for Class I optical devices such as frames and reading glasses.