Overview
EN ISO 24157:2008 (ISO 24157:2008) - "Ophthalmic optics and instruments - Reporting aberrations of the human eye" - specifies standardized methods for reporting ocular optical aberrations. Published by CEN/ISO, this standard defines coordinate systems, terminology (line of sight, wavefront error, OPD), and accepted representations of wavefront data for consistent communication of eye aberration measurements across clinical, research and manufacturing settings.
Key topics and technical requirements
- Scope and normative references: Establishes reporting conventions and cites ISO 8429 where applicable.
- Coordinate system: Defines the pupil and angular/Cartesian coordinates used to locate wavefront samples and define meridional angle (θ).
- Wavefront representations:
- Zernike polynomial function coefficients (normalized and un‑normalized) as a principal method to represent wavefront error across an aperture.
- Wavefront gradient fields or direct wavefront error function values as alternative representations.
- Data presentation formats:
- Normalized Zernike coefficients (including magnitude/axis form).
- Topographical maps of wavefront or OPD data for visualization.
- Methods for presentation of pooled aberration data for groups or populations.
- Quality metrics:
- Definitions and calculation of RMS wavefront error and exclusion of piston/tilt from degradation metrics.
- Gradient fit error and guidance on fitting wavefront slopes.
- Conversion and computational annexes:
- Annex A–E provide practical algorithms and tables: methods to generate Zernike coefficients from slope data, conversions for aperture size/decentration/rotation, notation conversions, derivative weighting matrices, and normalized Zernike tables (to 6th radial order).
Applications and who uses this standard
EN ISO 24157:2008 is intended for consistent reporting and interpretation of ocular aberration measurements. Typical users include:
- Manufacturers of aberrometers, wavefront sensors and ophthalmic instruments - for data output formats and interoperability.
- Clinical practitioners and optometrists/ophthalmologists - to interpret and report higher‑order aberrations in diagnostics and pre/post‑operative assessment.
- Researchers in vision science and optics - for reproducible representation of wavefront data and pooled population studies.
- Regulatory bodies and standards committees - for device conformity and reporting requirements.
Practical uses include aberrometry reporting, evaluation of higher‑order aberrations, design and assessment of corrective optics (lenses, contact lenses, refractive surgery planning), and comparative research across instruments or studies.
Related standards
- ISO 8429 (referenced normative document) and other optics/ophthalmic standards developed by ISO/TC 172 and CEN/TC 170.
Keywords: EN ISO 24157:2008, ISO 24157:2008, ophthalmic optics, aberrations of the human eye, Zernike coefficients, wavefront error, aberrometry, RMS wavefront error, topographical maps.
