MDCG 2025-8 Rev.1: Guidance on Master UDI-DI for Spectacle Devices

The Medical Device Coordination Group (MDCG) has published MDCG 2025-8 Rev.1 (March 2026), providing guidance on the implementation of the Master UDI-DI system for spectacle frames, spectacle lenses, and ready-to-wear reading spectacles.

The document supports the application of Commission Delegated Regulation (EU) 2025/1920, which introduced provisions on the assignment of Master UDI-DI for these devices under the EU MDR.

Scope of the guidance

The guidance aims to support manufacturers in the implementation of Master UDI-DI requirements, including:

• Structure and assignment of Master UDI-DI

• Labelling requirements

• Registration in EUDAMED

It should be read in conjunction with:

• Regulation (EU) 2017/745 (MDR)

• Commission Delegated Regulation (EU) 2025/1920

• MDCG 2025-7 and other UDI guidance documents

Master UDI-DI concept

Master UDI-DI is defined as a unique identifier used for grouping highly individualised devices (HIDs), including spectacle frames, lenses, and ready-to-wear reading spectacles.

These devices are grouped based on:

• Same intended purpose

• Same essential design characteristics

• Same combination of design parameters

Master UDI-DI acts as the access key to the device dataset in EUDAMED.

Assignment rules

The document clarifies that Master UDI-DI assignment differs from traditional UDI-DI rules and follows specific criteria depending on device type.

Spectacle frames

• Based on:

  • Frame construction

  • Frame material

  • Horizontal boxed lens size

Spectacle lenses

• Based on:

  • Lens design and material

  • Groups of spherical equivalent power

  • Groups of addition power

  • Groups of vision impairments

Ready-to-wear reading spectacles

• Based on:

  • Frame construction

  • Frame material

  • Lens material

  • Horizontal boxed lens size

  • Lens spherical power

The document includes decision trees and assignment examples (see Annex, pages 29–33).

It also clarifies that brand names, trademarks and catalogue numbers are not assignment triggers.

Labelling and packaging

• The UDI (Master UDI-DI + UDI-PI) must be applied according to MDR Annex VI, Part C.

• Labelling examples are provided (pages 20 and 26), but are illustrative only and do not represent mandatory layouts.

• For packaging:

  • Higher packaging levels may require their own identifiers

  • In many cases, higher-level packaging is considered logistic shipping containers and may not require a Master UDI-DI reflecting contents

Vigilance reporting

For vigilance reporting:

• Manufacturers must provide the UDI (Master UDI-DI + UDI-PI) in the Manufacturer Incident Report (MIR)

• This applies to both PDF MIR and EUDAMED modules

• Additional internal traceability may be required to identify specific devices within a grouped Master UDI-DI

Timeline

• Delegated Regulation (EU) 2025/1920:

  • Published: 23 September 2025

  • Entered into force: 13 October 2025

• Application date: 1 November 2028

• A three-year transitional period applies

Devices placed on the market before this date are not required to bear a Master UDI-DI on the label.

Read the full documente below.