Overview
EN ISO 8980-2:2017 - Ophthalmic optics - Uncut finished spectacle lenses - Part 2: Specifications for power-variation lenses - defines optical and geometrical requirements and verification methods for uncut finished power‑variation spectacle lenses. Published by CEN as an adoption of ISO 8980-2:2017, the standard sets tolerances, test procedures and marking/identification rules used in manufacturing, inspection and conformity assessment of lenses whose power varies across the surface (e.g., progressive or other power‑variation lenses).
Key topics and technical requirements
- Scope & classification: Covers uncut finished lenses and classifies finished lenses into single‑vision, multifocal and power‑variation types.
- Reference conditions: Tolerances apply at 23 °C ± 5 °C and at specified reference wavelengths.
- Optical verification: Measurements must use a focimeter conforming to ISO 8598‑1; optical tolerances are applied at defined reference points.
- Power tolerances: Specifies tolerances on back‑vertex power and cylindrical power that vary by power range (many common ranges use ±0.12 D; tolerances increase for higher dioptric values).
- Cylinder axis: Axis tolerance depends on cylindrical power (for cylinder ≥0.12 D axis tolerances range from ±14° down to ±2° as power increases).
- Variation (addition) power: Tolerance for variation/addition power is specified (example: ≤4.00 D → ±0.12 D; >4.00 D → ±0.18 D).
- Prismatic power & reference point: Defines how to verify total prism (including ordered and thickness‑reduction prism) and applicable tolerances.
- Geometrical and material checks: Requirements for size, thickness, polarizing orientation, surface/material quality, marking and information on packaging.
- Verification methods: Detailed procedures are in Clauses 6.x for back‑vertex power, cylinder axis, prism, variation/addition power and surface inspection.
Practical applications
- Quality control and acceptance testing in spectacle lens manufacturing
- Incoming inspection for laboratory and distribution centers
- Compliance and conformity assessment to meet EU/CEN or national requirements
- Procurement specifications for optical labs, retailers and healthcare providers
- R&D and product development for progressive/power‑variation lens designs
Who should use this standard
- Lens manufacturers and optical laboratories
- Optometrists and ophthalmic dispensers involved in lens verification
- Regulatory bodies, conformity assessment bodies and procurement teams
- Product managers and R&D engineers in ophthalmic optics
Related standards
Keywords: EN ISO 8980-2:2017, ophthalmic optics, uncut finished spectacle lenses, power‑variation lenses, tolerances, verification methods, focimeter, back‑vertex power, cylinder axis.
