ISO 8980-1:2004 pdf free.Ophthalmic optics — Uncut finished spectacle lenses — Part 1: Specifications for single-vision and multifocal lenses.
This part of ISO 8980 specifies requirements for the optical and geometrical properties for uncut finished single-vision and multifocal spectacle lenses.
2 Normative references
ISO 7944, Optics and optical instruments — Reference wavelengths
ISO 8429, Optics and optical instruments — Ophthalmology — Graduated dial scale
ISO 8598, Optics and optical instruments — Focimeters
ISO 13666, Ophthalmic optics — Spectacle lenses — Vocabulary
ISO 14889:2003, Ophthalmic optics — Spectacle lenses — Fundamental requirements for uncut finished lenses
4 Classification Finished lenses are classified as follows:
a) single-vision finished lenses;
b) multifocal finished lenses;
c) progressive power finished lenses.
5.2.1 General
The optical tolerances shall apply at the reference points of the lens at one of the reference wavelengths specified in ISO 7944.
The as-worn position can result in the apparent power to the eye being different from that determined as a result of the focimeter measurement.
If the manufacturer has applied corrections to compensate for the as-worn position, then the tolerances shall apply to the corrected value and this corrected value shall be stated by the manufacturer on the package or in an accompanying document (see Clause 7).
5.2.2 Tolerances on the focal power of single-vision lenses and multifocal lenses for the distance portion (back vertex power)
5.2.2.1 Focal power
The focal power shall be determined using a focimeter complying with ISO 8598 and using the method described in 6.2 or an equivalent method.
NOTE An ISO Technical Report is currently under preparation, which describes those parameters affecting the accuracy and inter- and intra-instruments repeatability of measurement with focimeters, both in general and in relation to off-axis measurements, e.g. the near portion of multifocal and progressive power lenses.
5.2.2.3 Tolerances on the direction of cylinder axis
The tolerances on the direction of the cylinder axis as specified in Table 2, shall be measured using the method described in 6.3. The cylinder axes shall be specified in accordance with ISO 8429.
These tolerances apply to multifocal lenses and to single-vision lenses with a predetermined orientation, e.g. prism base setting.ISO 8980-1:2004 pdf free download.