A Guide to MDCG 2025-8 for Spectacle Frames, Lenses, and Reading Glasses

WHAT IS THE MASTER UDI-DI AND WHY IS IT IMPORTANT?

The Master UDI-DI is a regulatory solution designed to reduce the burden of UDI management for medical devices that come in a large number of variants. As outlined in the EU MDR 2017/745, each medical device placed on the EU market requires a Basic UDI-DI and individual UDI-DIs. However, when manufacturers offer products like spectacle frames, lenses, or reading spectacles in many combinations (e.g., color, size, shape), assigning and maintaining separate entries for each in EUDAMED can be impractical.

The Master UDI-DI allows manufacturers to group such high-variant Class I devices that have common regulatory characteristics under a single master identifier. This grouped identifier is then used for device registration in EUDAMED, thereby simplifying submissions and post-market activities while preserving traceability and safety.

SCOPE OF MDCG 2025-8: WHAT DEVICES ARE COVERED?

MDCG 2025-8 applies specifically to three categories of low-risk optical products, classified under Class I medical devices:

Spectacle Frames – Medical frames designed to support prescription lenses. These may differ in color, size, shape, or finish.
Spectacle Lenses – Including uncut lenses that are later cut and fitted into frames. These can vary by material, power, and coatings.
Ready-to-Wear Reading Spectacles – Prefabricated reading glasses with non-individualized power and identical lens values.

This guidance helps ensure that such products, which typically undergo limited clinical risk, can be managed more efficiently from a regulatory standpoint using a Master UDI-DI model.

Overview Table: Unique Device Identifiers For Optical Devices

The table below compares different device identifiers given by the assignment of Master UDI DI for spectacle frames, spectacle lenses and ready-to-wear reading spectacles.

Identifiers	Spectacle frame, spectacle lenses, ready-to-wear reading spectacle	On the device label	In EUDAMED
Basic UDI-DI	Yes	No	Yes
Master UDI-DI	Yes	Yes	Yes
UDI-PI	Yes	Yes	No

Master UDI-DI and UDI-PI forms the UDI per EU MDR 2017/745.

Manufacturer’s Basic UDI-DI and Master UDI-DI are linked to the manufacturer.
Each combination of Basic UDI-DI parameter values forms the scope of 1 Basic UDI-DI.
1 Master UDI-DI is assigned to a device sharing the same combination of Basic UDI-DI parameters and Master UDI-DI design parameters (discrete values or defined range).
1 Master UDI-DI can be linked to only 1 Basic UDI-DI, but 1 Basic UDI-DI can be linked to multiple Master UDI-DIs.

CHALLENGES IN APPLYING UDI TO HIGH-VARIANT OPTICAL DEVICES

The typical UDI framework requires a unique UDI-DI for every product variant. For optical devices, this would mean generating thousands of UDIs just for minor differences in design (e.g., color or bridge width). This requirement poses significant administrative challenges, especially for spectacle manufacturers producing in bulk with numerous variants.

MDCG 2025-8 acknowledges that not all variations affect the clinical or safety profile of the device. Thus, by grouping certain non-safety-related variations under a Master UDI-DI, manufacturers can significantly reduce the complexity of EUDAMED registration, labeling, and post-market surveillance obligations.

REGULATORY BASIS: ARTICLE 29 AND ANNEX VI OF EU MDR 2017/745

The legal foundation of the Master UDI-DI concept is embedded in the MDR 2017/745:

Article 29(1) requires that manufacturers assign a UDI-DI and register it in EUDAMED for every device they place on the market.
Annex VI Part C defines the structure and relationship between Basic UDI-DI (serving as the identifier for a device group) and individual UDI-DIs (specific to each marketed version).

The MDCG 2025-8 guidance expands upon these principles by detailing how optical device manufacturers can use a Master UDI-DI as a grouping mechanism while still adhering to regulatory and traceability requirements.

WHAT IS THE MASTER UDI-DI SOLUTION?

The Master UDI-DI is not a replacement for the Basic UDI-DI. Rather, it serves as a higher-level identifier for grouping multiple UDI-DIs that share the same regulatory characteristics. Think of it as a logical umbrella under which all UDI-DIs for similar variants are linked.

Each device still receives its own UDI-DI (for traceability and product-specific labeling), but these are grouped under the Master UDI-DI when submitted to EUDAMED. This simplifies device registration and lifecycle updates without compromising transparency or compliance.

This concept is voluntary and is intended only for specific product types where the underlying medical function and risk classification remain constant across variations.

CONDITIONS FOR USING THE MASTER UDI-DI

To implement this solution, manufacturers must ensure that all grouped products meet the following conditions:

Same Intended Purpose: All variants must be intended for the same clinical use.
Same Risk Class and Conformity Pathway: All products grouped must be Class I and follow the same conformity assessment procedure under the MDR.
Non-Impacting Variations: Differences such as lens strength, shape, color, frame width, or coating types are permitted only if they do not impact the safety or performance of the device.
Mapping of UDI-DIs to Master: A clear mapping must be maintained internally by the manufacturer to show which UDI-DIs fall under which Master UDI-DI.

This internal mapping must be made available to competent authorities and Notified Bodies during audits or inspections.

HOW TO REGISTER MASTER UDI-DI IN EUDAMED

To use the Master UDI-DI model in practice, manufacturers must:

Assign a Basic UDI-DI for the device family, as per Annex VI.
Group individual UDI-DIs under a Master UDI-DI, referencing them in EUDAMED submissions.
Indicate the master relationship when completing UDI/device registration in EUDAMED’s UDI/Device module.
Maintain an internal correlation list between each UDI-DI and its respective Master UDI-DI.

It is essential to note that while the Master UDI-DI simplifies registration, it does not eliminate the need to provide UDI information on product labels or packaging as required.

PRACTICAL EXAMPLES FROM THE GUIDANCE

The MDCG 2025-8 document includes examples such as:

A manufacturer offering spectacle frames in 3 sizes and 5 colors (totaling 15 variants) can assign a Master UDI-DI to group all variants sharing the same intended use and conformity procedure. Each of the 15 variants will still receive a unique UDI-DI but be grouped under one master code.
A supplier of ready-made readers with powers ranging from +1.0D to +3.5D in 0.5 increments, offered in 6 different frame colors, may use a single Master UDI-DI for the whole range, assuming risk and intended purpose remain constant.

These examples reflect how regulatory flexibility is balanced with traceability and safety.

BENEFITS FOR MANUFACTURERS AND NOTIFIED BODIES

Adopting the Master UDI-DI solution provides several advantages:

Reduced Registration Burden: Fewer entries to manage in EUDAMED.
Improved Supply Chain Efficiency: Easier documentation and streamlined product lifecycle management.
Audit Simplicity: Notified Bodies can assess a single master grouping rather than many individual variants.
Regulatory Compliance: Aligns with the MDR while adapting to real-world product complexity in the optics industry.

For Notified Bodies, this solution also facilitates the evaluation of post-market surveillance data for grouped products and enhances audit focus.

CONCLUSION

The Master UDI-DI solution is most effective for Class I optical devices that vary cosmetically or dimensionally but do not differ in regulatory requirements or clinical safety profile. Manufacturers with large variant portfolios such as optical retailers, frame manufacturers, and uncut lens suppliers stand to gain the most.

However, it is critical to ensure robust documentation, internal mapping, and justifications are maintained. This will not only assist during audits but also protect manufacturers from non-compliance risks in the event of product complaints or market surveillance triggers.

HOW MORULAA CAN HELP

At Morulaa, we specialize in guiding medical device manufacturers through EU MDR compliance, including UDI implementation and EUDAMED registrations. Whether you’re introducing high-variant devices like spectacle frames or navigating Master UDI-DI mapping, our regulatory experts ensure you stay compliant, efficient, and audit-ready.