EN ISO 8624:2020

SLOVENSKI STANDARD
01-september-2020
Nadomešča:
SIST EN ISO 8624:2011
SIST EN ISO 8624:2011/A1:2015
Očesna optika - Okvirji očal - Merilni sistem in izrazje (ISO 8624:2020)
Ophthalmic optics - Spectacle frames - Measuring system and terminology (ISO
8624:2020)
Augenoptik - Brillenfassungen - Maßsystem und Begriffe (ISO 8624:2020)
Optique ophtalmique - Montures de lunettes - Système de mesure et terminologie (ISO
8624:2020)
Ta slovenski standard je istoveten z: EN ISO 8624:2020
ICS:
01.040.11 Zdravstveno varstvo Health care technology
(Slovarji) (Vocabularies)
11.040.70 Oftalmološka oprema Ophthalmic equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 8624
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2020
EUROPÄISCHE NORM
ICS 11.040.70 Supersedes EN ISO 8624:2011
English Version
Ophthalmic optics - Spectacle frames - Measuring system
and vocabulary (ISO 8624:2020)
Optique ophtalmique - Montures de lunettes - Système Augenoptik - Brillenfassungen - Maßsystem und
de mesure et terminologie (ISO 8624:2020) Begriffe (ISO 8624:2020)
This European Standard was approved by CEN on 28 June 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8624:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 8624:2020) has been prepared by Technical Committee ISO/TC 172 "Optics and
photonics" in collaboration with Technical Committee CEN/TC 170 “Ophthalmic optics” the secretariat
of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by January 2021, and conflicting national standards shall
be withdrawn at the latest by January 2021.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 8624:2011.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 8624:2020 has been approved by CEN as EN ISO 8624:2020 without any modification.

INTERNATIONAL ISO
STANDARD 8624
Fourth edition
2020-06
Ophthalmic optics — Spectacle frames
— Measuring system and vocabulary
Optique ophtalmique — Montures de lunettes — Système de mesure
et terminologie
Reference number
ISO 8624:2020(E)
©
ISO 2020
ISO 8624:2020(E)
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
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CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

ISO 8624:2020(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Principal terms of the boxed lens system . 1
3.2 Complementary terms of the boxed lens system . 6
4 Measuring system .12
Annex A (informative) Measurement of 3-dimensionally shaped spectacle frames .13
Bibliography .16
ISO 8624:2020(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee
SC 7, Ophthalmic optics and instruments, in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/TC 170, Ophthalmic optics, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This fourth edition cancels and replaces the third edition (ISO 8624:2011), which has been technically
revised. It also incorporates the Amendment ISO 8624:2011/Amd.1.
The main changes compared to the previous edition are as follows:
— the informative annex with its complementary definitions has been transferred to 3.2;
— minor asymmetry of only the nasal bearing surfaces has been included in this edition. Since such
asymmetry does not affect the lens shapes, only the definition of bridge height is affected. See the
explanation in 3.2.6, Note 2 to entry.
— the plane of the lens shape has been redefined and now relates to the orientation and position of the
vertical centre line, in turn based on the apex of the groove in the frame and not a dummy lens;
— the definition of overall length of side for those without joints has been amended slightly, while the
Figures now take account of the 3-dimensional nature of spectacle fronts where there is a significant
face form angle;
— an informative annex (Annex A) has been added to discuss measurement of 3-dimensional
spectacle frames.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

INTERNATIONAL STANDARD ISO 8624:2020(E)
Ophthalmic optics — Spectacle frames — Measuring
system and vocabulary
1 Scope
This document specifies a measuring system for spectacle frames and related vocabulary. It is applicable
to spectacle frames with fronts that are intended to be symmetrical.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
1)
3.1 Principal terms of the boxed lens system
3.1.1
boxed lens system
system of measurement and definitions of spectacle frames based on rectangular boxes that
circumscribe the lens shapes and that are used for the determination of the dimensions of the spectacle
front and in which the upper tangent is both common to the right and left lens shapes and regarded as
being horizontal
Note 1 to entry: In the case of spectacle frames having a significant face form angle, the line touching the
uppermost edges of the right and left lens shapes shall be regarded as horizontal.
Note 2 to entry: For measurement of a lens aperture, the measurements should be taken as if projected onto the
base of the rectangular box which is regarded as being tangential to the plane of the lens shape at its boxed centre.
This plane is close to that formed by the upper and lower tangents to the lens shape. For frame measurements,
the aperture is taken to be the size of the hypothetical lens that fits the frame. Measurements to the apex of the
groove or equivalent can give slightly different values.
Note 3 to entry: Since the tangent common to the right and left lens shapes is regarded as being horizontal, the
lines at right angles to it, e.g. the two sides of the box either side of the lens shape, are called "vertical". While
the frame is worn, the horizontal lines will remain horizontal if the head is held erect, but the vertical lines will
frequently not be vertical but, although in a vertical plane, will have their lower ends tipped in towards the
cheeks (see the as-worn pantoscopic angle in ISO 13666).
1) This clause contains the three most important dimensions for spectacle frames, horizontal boxed lens size,
distance between lenses and overall length of side. Tolerances on these are specified in ISO 12870.
ISO 8624:2020(E)
3.1.2
boxed centre
C
intersection of the horizontal centreline (3.2.1) and vertical centreline (3.2.2) of the rectangular box that
circumscribes the lens shape (3.2.10)
Note 1 to entry: See Figure 1.
3.1.3
horizontal boxed lens size
horizontal lens size
a
distance between the two vertical sides of the rectangular box that circumscribes the lens shape (3.2.10)
Note 1 to entry: For spectacle frames having a significant face form angle, the horizontal boxed lens size shall be
measured in the respective plane of the lens shape.
Note 2 to entry: See Figure 1.
3.1.4
vertical boxed lens size
vertical lens size
b
distance between the two horizontal sides of the rectangular box that circumscribes the lens shape
(3.2.10)
Note 1 to entry: See Figure 1.
Key
C , C right, left boxed centre
R L
a horizontal boxed lens size
b vertical boxed lens siz
...