What is ISO 13666 about?
ISO 13666 defines terms relating to ophthalmic optics, specifically to blanks, finished spectacle lenses and fitting purposes.
Vocabulary specified in ISO 13666 helps you avoid ambiguity and ensure consistency in the terminologies used in relation to spectacle lenses.
Who is ISO 13666 for?
ISO 13666 on spectacle lenses- vocabulary is useful for:
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Practitioners of ophthalmic optics
- Manufacturers and suppliers of spectacle lenses
Why should you use ISO 13666?
The vastness and technical nature of terminologies related to spectacle lenses calls for a standardized set of all definitions. This allows you to ensure uniformity in the terms used for spectacle lenses locally and globally.
ISO 13666 presents you a comprehensive set of terms related to ophthalmic optics and spectacle lenses, so as to eliminate ambiguities and inconsistencies in their use.
What’s changed since the last update?
BS EN ISO 13666:2019 supersedes EN ISO 13666:2012.
This third edition BS EN ISO 13666:2019 replaces the second edition ISO 13666:2012, which has been technically revised.
The main changes compared to the previous edition are as follows:
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Since the document is for spectacle lens terminology, the single word “lens” rather than “spectacle lens” is used throughout the document.
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This revision has resulted in a few terms that were no longer used in lens standards or in communications between participants in the lens manufacturing and dispensing chain being deleted. The terms that were in clause 17 have been either moved or incorporated into earlier terms.
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Over 50 % of terms and definitions have been revised. In some cases, this is as little as changing the order of synonyms for the term, to significant changes in the wording of definitions or notes to entry, but without change of meaning.
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The meaning of vertex distance has been altered so that it now refers to the horizontal distance between the back surface of the lens and the apex of the cornea, measured with the eyes in the primary position. The plane of the lens shape is now defined as being the plane containing the vertical centreline parallel to the horizontal centreline of the individual lens based on the apex of the groove instead of being based on the plane tangential to the demonstration lens. The design reference points are where the manufacturer's specifications apply, while the reference points are where the lenses are to be verified. For single-vision and most multifocal lenses, these are the same. The previous distinction for a multifocal lens, where the distance design reference point was usually the centre of the semi-finished lens blank (now called simply "blank") while the distance reference point was usually the intended position of the optical centre of the distance portion after surfacing, has been removed — they are the design reference point or simply the reference points of the blank and the finished lens.
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The term "as-worn" corrected dioptric power has been replaced by the term verification power — this word explains its purpose better, and is clarified by a new definition. Shape magnification has been replaced by the more general spectacle magnification.