ISO 8624:2020

Ophthalmic optics — Spectacle frames — Measuring system and vocabulary

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.

Optique ophtalmique — Montures de lunettes — Système de mesure et terminologie

Le présent document spécifie un système de mesure des montures de lunettes et la terminologie associée. Elle s'applique aux montures de lunettes dont les faces sont destinées à être symétriques.

General Information

• Status: Published
• Publication Date: 21-Jun-2020
• ICS: 11.040.70 - Ophthalmic equipment
• Technical Committee: ISO/TC 172/SC 7 - Ophthalmic optics and instruments
• Drafting Committee: ISO/TC 172/SC 7/WG 2 - Spectacle frames
• Current Stage: 6060 - International Standard published
• Start Date: 22-Jun-2020
• Due Date: 22-Jan-2021
• Completion Date: 22-Jun-2020

Relations

• Consolidates: ISO 15156-1:2015 - Petroleum and natural gas industries — Materials for use in H2S-containing environments in oil and gas production — Part 1: General principles for selection of cracking-resistant materials
• Effective Date: 06-Jun-2022
• Revises: ISO 8624:2011 - Ophthalmic optics — Spectacle frames — Measuring system and terminology
• Effective Date: 10-Feb-2018
• Revises: ISO 8624:2011/Amd 1:2015 - Ophthalmic optics — Spectacle frames — Measuring system and terminology — Amendment 1
• Effective Date: 10-Feb-2018

Standards Content (Sample)

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

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ISO 8624:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

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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 2020 – All rights reserved iii

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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

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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 2020 – All rights reserved 1

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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 size
c boxed centre distance
d distance between lenses
Figure 1 — Measurements related to spectacle frames — Spectacle fronts
2 © ISO 2020 – All rights reserved

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ISO 8624:2020(E)

3.1.5
boxed centre distance
c
horizontal distance between the boxed centres (3.1.2)
Note 1 to entry: See Figure 1.
Note 2 to entry: For spectacle frames having a significant face form angle, the boxed centre distance shall be
measured between the vertical centrelines passing through the groove of the frame aperture. See Figure 4.
3.1.6
distance between lenses
d
horizontal distance between the nasal vertical sides of the rectangular boxes that circumscribe the
right and left lens shapes (3.2.10)
Note 1 to entry: See Figure 1.
3.1.7
overall length of side
l
length from the intersection of the dowel screw's axis with the median plane of the joint to the end of
the side and parallel to the centreline of it, the drop having been straightened
Note 1 to entry: See Figure 2.
0
Note 2 to entry: For sides without a joint, the side should be held open at ( 90 )° to the front or to that part of
−5
the side (the lug) that is intended to be attached to the front, and the length measurement is from the end of the
side to the back surface of the lug less 10 mm. See Figure 3.
© ISO 2020 – All rights reserved 3

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ISO 8624:2020(E)

Key
1 axis of joint or dowel screw axis
2 median plane of joint
3 centreline of side
4 length to bend (see 3.2.7)
5 length of drop (see 3.2.8)
l overall length of side (l = dimensions 4 + 5)
X detail of the measurement position at the intersection of the three lines at the joint
Figure 2 — Measurements related to spectacle frames — Spectacle sides
4 © ISO 2020 – All rights reserved

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ISO 8624:2020(E)

Dimension in millimetres
Key
l overall length of side
Figure 3 — Measurement of overall length of side for sides without a joint
© ISO 2020 – All rights reserved 5

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ISO 8624:2020(E)

Key
C , C right, left boxed centre
R L
a* horizontal boxed lens size
b* vertical boxed lens size
c boxed centre distance
d distance between lenses
1 , 1 right, left horizontal centreline
R L
2 left vertical centreline
L
3 , 3 right, left plane of the lens shape
R L
4 , 4 right, left face form angle
R L
NOTE In this Figure, a* and b* are the size measured to the apex of th
...

NORME ISO
INTERNATIONALE 8624
Quatrième édition
2020-06
Optique ophtalmique — Montures
de lunettes — Système de mesure et
terminologie
Ophthalmic optics — Spectacle frames — Measuring system and
vocabulary
Numéro de référence
ISO 8624:2020(F)
©
ISO 2020

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ISO 8624:2020(F)

DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2020
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,
y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut
être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
ISO copyright office
Case postale 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Genève
Tél.: [phone]
E-mail: [e-mail]
Web: www.iso.org
Publié en Suisse
ii © ISO 2020 – Tous droits réservés

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ISO 8624:2020(F)

Sommaire Page
Avant-propos .iv
1 Domaine d'application . 1
2 Références normatives . 1
3 Termes et définitions . 1
3.1 Termes principaux relatifs au système d'encadrement du verre . 1
3.2 Termes complémentaires relatifs au système d'encadrement du verre . 6
4 Système de mesure .12
Annexe A (informative) Mesurage des montures de lunettes façonnées en 3 dimensions .13
Bibliographie .16
© ISO 2020 – Tous droits réservés iii

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ISO 8624:2020(F)

Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes
nationaux de normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est
en général confiée aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l'ISO participent également aux travaux.
L'ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui
concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents
critères d'approbation requis pour les différents types de documents ISO. Le présent document a été
rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir www
.iso .org/ directives).
L'attention est attirée sur le fait que certains des éléments du présent document peuvent faire l'objet de
droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable
de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant
les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de
l'élaboration du document sont indiqués dans l'Introduction et/ou dans la liste des déclarations de
brevets reçues par l'ISO (voir www .iso .org/ brevets).
Les appellations commerciales éventuellement mentionnées dans le présent document sont données
pour information, par souci de commodité, à l'intention des utilisateurs et ne sauraient constituer un
engagement.
Pour une explication de la nature volontaire des normes, la signification des termes et expressions
spécifiques de l'ISO liés à l'évaluation de la conformité, ou pour toute information au sujet de l'adhésion
de l'ISO aux principes de l'Organisation mondiale du commerce (OMC) concernant les obstacles
techniques au commerce (OTC), voir le lien suivant: www .iso .org/ iso/ fr/ avant -propos.
Ce document a été élaboré par le comité technique TC 172, Optique et photonique, et le sous-comité
SC 7, Optique et instruments ophtalmiques, en collaboration avec le Comité européen de normalisation
(CEN), le comité technique CEN/TC 170, Optique ophtalmique, conformément à l'Accord de coopération
technique entre l'ISO et le CEN (Accord de Vienne).
Cette quatrième édition annule et remplace la troisième édition (ISO 8624:2011), qui a fait l'objet d'une
révision technique. Elle incorpore également l'Amendement ISO 8624:2011/Amd.1.
Les principales modifications par rapport à l'édition précédente sont les suivantes:
— l'annexe informative et ses définitions complémentaires ont été déplacées en 3.2;
— la présente édition tient compte d'une asymétrie mineure des zones d'appui nasales uniquement.
Dans la mesure où cette asymétrie n'a pas d'incidence sur les formes du verre, seule la définition de
la hauteur du pont est affectée. Voir l'explication en 3.2.6, note 2 à l'article;
— le plan de la forme du verre a été redéfini et concerne maintenant l'orientation et la position de la
ligne médiane verticale, s'appuyant elle-même sur le sommet du drageoir dans la monture et non
sur un verre de présentation (factice);
— la définition de la longueur totale d'une branche pour des branches sans charnière a été légèrement
modifiée, tandis que les figures tiennent maintenant compte de la nature tridimensionnelle des
faces de lunettes où l'angle de forme de face est important;
— une annexe informative (Annexe A) a été ajoutée afin de traiter du mesurage tridimensionnel des
montures de lunettes.
iv © ISO 2020 – Tous droits réservés

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ISO 8624:2020(F)

Il convient que l'utilisateur adresse tout retour d'information ou toute question concernant le présent
document à l'organisme national de normalisation de son pays. Une liste exhaustive desdits organismes
se trouve à l'adresse www .iso .org/ fr/ members .html.
© ISO 2020 – Tous droits réservés v

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NORME INTERNATIONALE ISO 8624:2020(F)
Optique ophtalmique — Montures de lunettes — Système
de mesure et terminologie
1 Domaine d'application
Le présent document spécifie un système de mesure des montures de lunettes et la terminologie
associée. Elle s'applique aux montures de lunettes dont les faces sont destinées à être symétriques.
2 Références normatives
Le présent document ne contient aucune référence normative.
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions suivants s'appliquent.
L'ISO et l'IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en
normalisation, consultables aux adresses suivantes:
— ISO Online browsing platform: disponible à l'adresse https:// www .iso .org/ obp
— IEC Electropedia: disponible à l'adresse http:// www .electropedia .org/
1)
3.1 Termes principaux relatifs au système d'encadrement du verre
3.1.1
système d'encadrement du verre
système de mesure et de définition des montures de lunettes basé sur les boîtes rectangulaires qui
circonscrivent les formes du verre et qui sont utilisés pour la détermination des dimensions de la face
des lunettes et dans lesquels la tangente supérieure est commune aux formes des verres droit et gauche
et considérée comme horizontale
Note 1 à l'article: Dans le cas de montures de lunettes présentant un angle de forme de face important, la ligne
touchant les bords supérieurs des formes des verres droit et gauche doit être considérée comme horizontale.
Note 2 à l'article: Pour mesurer l'ouverture d'un verre, il convient d'utiliser les mesures telles que projetées sur
la base de la boîte rectangulaire, considérée comme tangente au plan de la forme du verre au centre de la boîte.
Ce plan est proche de celui formé par les tangentes supérieure et inférieure à la forme du verre. Pour mesurer la
monture, la taille de l'ouverture choisie est celle de la taille hypothétique du verre qui rentre dans la monture.
Les mesures au sommet du drageoir, ou similaire, peuvent donner des valeurs légèrement différentes.
Note 3 à l'article: Étant donné que la tangente commune aux formes des verres droit et gauche est considérée
comme horizontale, les droites perpendiculaires à celle-ci (par exemple les deux côtés de la boîte de part et
d'autre de la forme du verre) sont appelées «lignes verticales». En condition de port, les lignes horizontales de la
monture restent horizontales si la tête est droite, alors que les lignes verticales sont très souvent non verticales,
bien que dans un plan vertical, leurs extrémités inférieures soient inclinées en direction des joues (voir angle
pantoscopique au porté dans l'ISO 13666).
1) Cet article contient les trois dimensions les plus importantes relatives aux montures de lunettes: la dimension
horizontale d'encadrement du verre, la distance entre les verres et la longueur totale de la branche. Les tolérances
sont spécifiées dans l'ISO 12870.
© ISO 2020 – Tous droits réservés 1

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ISO 8624:2020(F)

3.1.2
centre de la boîte
C
intersection de la ligne médiane horizontale (3.2.1) et de la ligne médiane verticale (3.2.2) de la boîte
rectangulaire qui circonscrit la forme du verre (3.2.10)
Note 1 à l'article: Voir Figure 1.
3.1.3
dimension horizontale d'encadrement du verre
dimension horizontale du verre
a
distance entre les deux côtés verticaux de la boîte rectangulaire qui circonscrit la forme du verre (3.2.10)
Note 1 à l'article: Pour les montures de lunettes présentant un angle de forme de face important, la dimension
horizontale d'encadrement du verre doit être mesurée dans le plan respectif de la forme du verre.
Note 2 à l'article: Voir Figure 1.
3.1.4
dimension verticale d'encadrement du verre
dimension verticale du verre
b
distance entre les deux côtés horizontaux de la boîte rectangulaire qui circonscrit la forme du verre
(3.2.10)
Note 1 à l'article: Voir Figure 1.
Légende
C , C centre de la boîte du verre droit, du verre gauche
R L
a dimension horizontale d'encadrement du verre
b dimension verticale d'encadrement du verre
c distance entre les centres des boîtes
d distance entre les verres
Figure 1 — Mesures relatives aux montures de lunettes — Faces de lunettes
2 © ISO 2020 – Tous droits réservés

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ISO 8624:2020(F)

3.1.5
distance entre les centres des boîtes
c
distance horizontale entre les centres des boîtes (3.1.2)
Note 1 à l'article: Voir Figure 1.
Note 2 à l'article: Pour les montures de lunettes présentant un angle de forme de face important, la distance
entre les centres des boîtes doit être mesurée entre les lignes médianes verticales qui passent par le drageoir de
l'ouverture de la monture. Voir Figure 4.
3.1.6
distance entre les verres
d
distance horizontale entre les côtés verticaux internes des boîtes rectangulaires qui circonscrivent les
formes des verres droit et gauche
Note 1 à l'article: Voir Figure 1.
3.1.7
longueur totale de la branche
l
longueur entre l'intersection de l'axe de la vis d'articulation avec le plan médian de la charnière et
l'extrémité de la branche, parallèle à sa ligne médiane, l'extrémité de la spatule ayant été redressée
Note 1 à l'article: Voir Figure 2.
Note 2 à l'article: Pour les branches sans charnière, il convient que la branche soit maintenue à une ouverture
0
de ( 90 )° de la face ou de la partie de la branche (le tenon) destinée à être reliée à la face, et le mesurage de la
−5
longueur se fait de l'extrémité de la branche à la surface arrière du tenon moins 10 mm. Voir Figure 3.
© ISO 2020 – Tous droits réservés 3

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ISO 8624:2020(F)

Légende
1 axe de la charnière ou axe de la vis d'articulation
2 plan médian de la charnière
3 ligne médiane de la branche
4 longueur au coude (voir 3.2.7)
5 longueur à l'extrémité de la spatule (voir 3.2.8)
l longueur totale de la branche (l = dimensions 4 + 5)
X détail du point de mesurage à l'intersection des trois lignes de la charnière
Figure 2 — Mesures relatives aux montures de lunettes — Branches de lunettes
4 © ISO 2020 – Tous droits réservés

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ISO 8624:2020(F)

Dimensions en millimètres
Légende
l longueur totale de la branche
Figure 3 — Mesurage de la longueur totale de la branche pour des branches sans charnière
© ISO 2020 – Tous droits réservés 5

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ISO 8624:2020(F)

Légende
C , C centre de la boîte du verre droit, du verre gauche
R L
a* dimension horizontale d'encadrement du verre
b* dimension verticale d'encadrement du verre
c distance entre les centres des boîtes
d distance entre les verres
1 , 1 ligne médiane horizontale droite, gauche
R L
2 ligne médiane verticale gauche
L
3 , 3 plan de la forme du verre droit, du verre gauche
R L
4 , 4 angle de forme de face droit, gauche
R L
NOTE Dans cette figure, a* et b* représentent la taille mesurée au sommet d
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 8624
ISO/TC 172/SC 7
Ophthalmic optics — Spectacle frames
Secretariat: DIN
— Measuring system and vocabulary
Voting begins on:
2020­04­01
Optique ophtalmique — Montures de lunettes — Système de mesure
et terminologie
Voting terminates on:
2020­05­27
ISO/CEN PARALLEL PROCESSING
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 8624:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2020

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ISO/FDIS 8624:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© 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
CP 401 • Ch. de Blandonnet 8
CH­1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/FDIS 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 2020 – All rights reserved iii

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ISO/FDIS 8624:2020(E)

Foreword
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electrotechnical standardization.
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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, Ophtalmic 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 3­dimensional
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.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 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 of the 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.
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ISO/FDIS 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 size
c boxed centre distance
d distance between lenses
Figure 1 — Measurements related to spectacle frames — Spectacle fronts
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ISO/FDIS 8624:2020(E)

3.1.5
boxed centre distance
c
horizontal distance between the boxed centres (3.1.2)
Note 1 to entry: See Figure 1.
Note 2 to entry: For spectacle frames having a significant face form angle, the boxed centre distance shall be
measured between the vertical centrelines passing through the groove of the frame aperture. See Figure 4.
3.1.6
distance between lenses
d
horizontal distance between the nasal vertical sides of the rectangular boxes that circumscribe the
right and left lens shapes (3.2.10)
Note 1 to entry: See Figure 1.
3.1.7
overall length of side
l
length from the intersection of the dowel screw's axis with the median plane of the joint to the end of
the side and parallel to the centreline of it, the drop having been straightened
Note 1 to entry: See Figure 2.
0
Note 2 to entry: For sides without a joint, the side should be held open at ( 90 )° to the front or to that part of
−5
the side that is intended to be attached to the front, and the length measurement is from the end of the side to the
back surface of the lug less 10 mm. See Figure 3.
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ISO/FDIS 8624:2020(E)

Key
1 axis of hinge or dowel screw axis
2 median plane of joint
3 centreline of side
4 length to bend (see 3.2.7)
5 length of drop (see 3.2.8)
l overall length of side (l = dimensions 4 + 5)
X detail of the measurement position at the intersection of the three lines at the joint
Figure 2 — Measurements related to spectacle frames — Spectacle sides
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ISO/FDIS 8624:2020(E)

Dimension in millimetres
Key
l overall length of side
Figure 3 — Measurement of overall length of side for sides without a joint
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ISO/FDIS 8624:2020(E)

Key
C , C right, left boxed centre
R L
a* horizontal b
...