Overview
ISO 11979-2:2014 - "Ophthalmic implants - Intraocular lenses - Part 2: Optical properties and test methods" defines requirements and reference test methods for the optical performance of intraocular lenses (IOLs). The scope covers spherical and aspheric, monofocal, toric, multifocal and accommodative optics and also includes phakic intraocular lenses (PIOL). The standard sets how to measure and judge dioptric power, imaging quality (resolution/MTF) and spectral transmittance under simulated in‑situ conditions.
Key topics and requirements
- Dioptric power
- Manufacturers must demonstrate the full power range meets specified tolerances at in‑situ conditions.
- Tolerance examples (spherical power S): 0–15 D ±0.3 D; 15–25 D ±0.4 D; 25–30 D ±0.5 D; >30 D ±1.0 D.
- Toric IOLs: meridional powers and spherical equivalent must meet tolerances; cylindrical power tolerances vary by cylinder magnitude and SE. Toric lenses require a visible physical axis indicator aligned within ≤5° of the low‑power meridian.
- Multifocal IOLs: far power and addition(s) have specified tolerance bands for both far and add powers.
- Imaging quality
- Two accepted evaluation approaches: Resolution efficiency (Annex B) or Modulation Transfer Function (MTF) (Annex C).
- Monofocal acceptance examples (model eye 1 / MTF): MTF ≥ 0.43 at 100 mm, or ≥ 70% of theoretical max (but ≥ 0.28 minimum).
- Multifocal, toric and accommodative IOLs have specific MTF/resolution requirements and test‑aperture guidance (small vs large apertures for near/far assessments).
- Spectral transmittance
- Included for information (UV transmission, laser‑source interactions). No pass/fail requirement but testing method is provided.
- Reference methods and annexes
- Annex A: measurement of dioptric power; Annex B: resolution efficiency; Annex C: MTF measurement and model eye specifications. Alternative methods allowed if equivalence to reference methods is demonstrated.
Applications and users
- IOL manufacturers: design verification, production quality control, labelling claims (stated dioptric power and imaging performance).
- Test laboratories / metrology teams: implement Annex A–C reference methods for certification and validation.
- Regulatory bodies and notified bodies: evaluate conformity of IOLs to international optical performance benchmarks.
- R&D and clinical engineers: correlate optical bench metrics (MTF, resolution) with expected clinical outcomes.
Related standards
- ISO 11979 series (Part 1 Vocabulary; Part 3 Mechanical; Part 4 Labelling; Part 5 Biocompatibility; Part 9 Multifocal; Part 10 Phakic IOLs, etc.)
- ISO 9334 / ISO 9335 (OTF/MTF definitions and measurement procedures)
- ISO 6328 (resolving power)
Keywords: ISO 11979-2:2014, intraocular lenses, IOL, optical properties, test methods, dioptric power, MTF, resolution efficiency, toric IOL, multifocal IOL, spectral transmittance.
Open preview (PDF)Ophthalmic implants — Intraocular lenses — Part 2: Optical properties and test methods