In November 2025, the Medical Device Coordination Group (MDCG) released guidance MDCG 2025-8, clarifying how the Master UDI-DI should be assigned to spectacles under the EU MDR 2017/745.
- Spectacle Frames: Basic UDI‑DIs are assigned per combination of frame construction (full‑rim, half‑rim, rimless, other types) and frame material (metal, plastic, combination, other types). The horizontal boxed lens size (typically 40–60 mm) is the Master UDI‑DI design parameter.
- Spectacle Lenses: Basic UDI‑DIs are assigned per combination of commercial index (including lens material type and refractive index) and lens design (single‑vision, multifocal, power‑variation, other types). Master UDI‑DIs group lenses by spherical equivalent power (mean sphere), addition power and similar vision‑impairment groupings derived from the nominal prescription.
- Ready-to-Wear Reading Spectacles: Basic UDI‑DIs are assigned per combination of frame construction, frame material and lens material (mineral or organic, including polycarbonate). Master UDI‑DIs are based on horizontal boxed lens size (typically 40–60 mm) and lens spherical power (from +1.00 D to +3.50 D).
Commission Delegated Regulation (EU) 2025/1920 entered into force on 13 October 2025 and applies from 1 November 2028; from that date, spectacles must bear a Master UDI‑DI (and use it in EUDAMED registration), but devices manufactured before 1 November 2028 do not need to be relabelled.
