The MDCG published MDCG 2025-8 Rev. 1 (March 2026), a guidance document on implementing Master UDI-DI for spectacle frames, spectacle lenses and ready-to-wear reading spectacles as highly individualised devices under the MDR.
The guidance clarifies how Basic UDI-DI and Master UDI-DI differ and how they are assigned and linked for these device families.
The assignment parameters (triggers) and practical decision trees:
- Spectacle frames: Basic UDI-DI uses frame construction + frame material; Master UDI-DI adds horizontal boxed lens size (discrete values).
- Spectacle lenses: Basic UDI-DI uses commercial index/material type + design; Master UDI-DI is driven by the intended purpose via spherical equivalent power (mean sphere) ranges, plus addition groups when relevant.
- Ready-to-wear reading spectacles: Basic UDI-DI uses frame construction + frame material + lens material; Master UDI-DI adds boxed lens size + lens spherical power.
- Labelling & vigilance: examples show how the UDI (Master UDI-DI + UDI-PI) may appear on labels; for serious incidents, the manufacturer should report the relevant UDI in MIR/EUDAMED.
- Implementation timeline: the underlying Delegated Regulation (EU) 2025/1920 applies from 01 Nov 2028 (after entry into force in Oct 2025), and devices produced before that date are not required to bear Master UDI-DI.
More info, here.