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ISO 8980-1:2004 pdf free

ISO 8980-1:2004 pdf free.Ophthalmic optics一Uncut finished spectacle lenses
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).
Tolerances on the focal power of single-vision lenses and multifocal lenses for the distance portion (back vertex 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.
Spectacle lenses shall comply with the tolerances on the power of each principal meridian, A, and with the tolerances on the cylindrical power, B (see Table 1).
As the size and thickness of lenses worked for a particular shape and size will inevitably be subject to the requirements of the spectacle frame to be glazed, the tolerances on size and thickness are not applicable to these lenses. Such tolerances may be agreed between the prescriber and supplier.
The thickness shall be measured at the distance reference point of the front surface and normal to this surface.
It shall not deviate from the nominal value by more than±0,3 mm.
The nominal thickness of the lens may be specified by the manufacturer or be agreed between the prescriber and the supplier. For lenses worked to prescription, see 5.3.1.
When using one of the methods described in 6.6, each of the segment dimensions (width, depth and intermediate depth) shall not deviate from its nominal value by more than±0,5 mm.
If sold as a matched pair, each of the segment dimensions (width, depth and intermediate depth) shall not differ by more than 0,7 mm.ISO 8980-1 pdf download.

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