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Illustration MDCG 2025-8: how should optics manufacturers manage the Master UDI-DI?

MDCG 2025-8: how should optics manufacturers manage the Master UDI-DI?

Medical devices regulation

Frames, corrective lenses and pre-fitted spectacles are among the most individualized devices on the market. Colors, geometries, materials, power combinations... an immense volume of variants that made the classic UDI-DI difficult to apply.

With the publication of MDCG 2025-7 in July, followed by MDCG 2025-8 on November 14, the Commission has finally provided a method adapted to these highly granular products. For manufacturers, the challenge is simple: ensure traceability without creating a chaos of identifiers.




What is the Master UDI-DI and why has the EU introduced it?

Master UDI-DI is an identifier designed for highly individualized devices. It groups together, under a single reference, variants that share the same intended use and the same essential design parameters.

The idea is to reduce unnecessary fragmentation of the UDI system, while maintaining MDR-compliant traceability. The Basic UDI-DI remains above, the UDI-DI remains used for operational identification, and the Master UDI-DI serves as the EUDAMED registration key for these specific families.




Which devices are covered?

The guide covers only :

  • spectacle frames,

  • corrective lenses,

  • pre-mounted reading glasses.


These three categories come under Class I, but their level of individualization makes UDI-DI impractical as it stands.




How to build a Master UDI-DI compliant with MDCG 2025-8?

The guide precisely defines the parameters to be taken into account when deciding whether several variants fall under the same UDI-DI Master. The approach consists of :

  • identify the essential design features ;

  • determine their stability within the same range;

  • group all consistent variants under a single UDI-DI Master;

  • create another UDI-DI Master as soon as a key parameter changes.


The hierarchical relationship becomes :

Basic UDI-DI → several Master UDI-DI → each Master UDI-DI groups together many potential UDI-DIs.




Regulatory impact for manufacturers

Manufacturers must integrate the Master UDI-DI into several processes:

  • labeling: presence of the Master UDI-DI and a suitable UDI-PI ;

  • registration: EUDAMED will use the Master UDI-DI as a pivot identifier;

  • PMS and vigilance: alerts will be based on this new identifier;

  • internal documentation: updated procedures for UDI assignment, labeling, variant management, PMS and vigilance.




How do MDCG 2025-7 and 2025-8 fit together?

The two documents are complementary:

  • MDCG 2025-8 explains how to build and apply a Master UDI-DI.

  • MDCG 2025-7 details the timetable and transitional logic.


Main deadlines :

  • 2026: mandatory EUDAMED registration for these devices.

  • 2028: mandatory application of Master UDI-DI.


The period 2026-2028 can be used for early adoption, to avoid an abrupt transition and to validate internal procedures before the formal obligation.




Case studies


Case study 1: a range of frames with multiple sizes and colors

Geometry, material and intended use remain identical. Variations in size or color do not affect the essential design parameters.

→ A single UDI-DI Master covers all variants.



Case study 2: lenses with several optical geometries

Same commercial range, same materials, but different geometries (monofocal, progressive, aspheric).

→ Each geometry represents a major change.

→ Several Master UDI-DI are required.




Mini-FAQ


What happens if a variant doesn't match any existing UDI-DI Master?

A new UDI-DI Master must be created, even if the commercial range remains the same.


Can I continue to use only the UDI-DI instead of the UDI-DI Master?

No. The Master UDI-DI becomes mandatory for these categories from 2028.


How many UDI-DI Masters can be associated with the same Basic UDI-DI?

As many as required. However, a UDI-DI Master can only be linked to one UDI-DI Basic.


Do distributors need to update their systems?

Yes, to integrate the new identifier into their logistics and traceability flows.


Are Class I optical devices still exempt from notified body requirements?

Yes, the level of risk does not change. The change only concerns identification.




In conclusion

The guides published in 2025 show a clear desire to simplify identification without reducing risk control. For many manufacturers, this evolution will make it possible to structure a UDI system that is more coherent and easier to maintain.

CSDmed can accompany these updates, in particular to adapt UDI procedures, labeling logic and EUDAMED registrations.Let's talk about it.




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