SIST EN ISO 21987:2017

SLOVENSKI STANDARD
01-november-2017
1DGRPHãþD
SIST EN ISO 21987:2010
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Ophthalmic optics - Mounted spectacle lenses (ISO 21987:2017)
Augenoptik - Fertig montierte Korrektionsbrillengläser (ISO 21987:2017)
Optique ophtalmique - Verres ophtalmiques montés (ISO 21987:2017)
Ta slovenski standard je istoveten z: EN ISO 21987:2017
ICS:
11.040.70 Oftalmološka oprema Ophthalmic equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 21987
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2017
EUROPÄISCHE NORM
ICS 11.040.70 Supersedes EN ISO 21987:2009
English Version
Ophthalmic optics - Mounted spectacle lenses (ISO
21987:2017)
Optique ophtalmique - Verres ophtalmiques montés Augenoptik - Fertig montierte Korrektionsbrillengläser
(ISO 21987:2017) (ISO 21987:2017)
This European Standard was approved by CEN on 26 May 2017.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21987:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Annex ZA (informative) Relationship between this document and the Essential
Requirements of Directive 93/42/EEC [OJ L 169] aimed to be covered . 5

European foreword
This document (EN ISO 21987:2017) 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 February 2018, and conflicting national standards
shall be withdrawn at the latest by February 2018.
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 21987:2009.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive(s).
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this
document.
The following referenced documents are indispensable for the application of this document. For
undated references, the latest edition of the referenced document (including any amendments) applies.
For dated references, only the edition cited applies. However, for any use of this standard ‘within the
meaning of Annex ZA’, the user should always check that any referenced document has not been
superseded and that its relevant contents can still be considered the generally acknowledged state-of-
art.
When an IEC or ISO standard is referred to in the ISO standard text, this shall be understood as a
normative reference to the corresponding EN standard, if available, and otherwise to the dated version
of the ISO or IEC standard, as listed below.
NOTE The way in which these referenced documents are cited in normative requirements determines the
extent (in whole or in part) to which they apply.
Table — Correlation between normative references and dated EN and ISO standards
Normative references as listed Equivalent dated standard
in Clause 2 of the ISO standard
EN ISO or IEC
ISO 7944 EN ISO 7944:1998  + AC:2009 ISO 7944:1998 + Cor.1:2009
ISO 8429 EN ISO 8429:1996 ISO 8429:1986
ISO 8598-1 EN ISO 8598-1:2014 ISO 8598-1:2014
ISO 8624 EN ISO 8624:2011 + A1:2015 ISO 8624:2011+ Amd.1:2015
ISO 8980-1 EN ISO 8980-1:2017 ISO 8980-1:2017
ISO 8980-2 EN ISO 8980-2:2017 ISO 8980-2:2017
ISO 13666 EN ISO 13666:2012 ISO 13666:2012
ISO 14889 EN ISO 14889:2013 ISO 14889:2013

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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 21987:2017 has been approved by CEN as EN ISO 21987:2017 without any modification.
Annex ZA
(informative)
Relationship between this document and the Essential Requirements of
Directive 93/42/EEC [OJ L 169] aimed to be covered
This document has been prepared under a Commission’s standardization request [M/023 concerning
the development of European Standards related to medical devices] to provide one voluntary means of
conforming to essential requirements of Council Directive 93/42/EEC of 14 June 1993 concerning
medical devices [OJ L 169].
Once this standard is cited in the Official Journal of the European Union under that Directive,
compliance with the normative clauses of this standard given in Table ZA.1 confers, within the limits of
the scope of this standard, a presumption of conformity with the corresponding essential requirements
of that Directive and associated EFTA regulations.
NOTE 1 Where a reference from a clause of this standard to the risk management process is made, the risk
management process needs to be in compliance with Directive 93/42/EEC as amended by 2007/47/EC. This
means that risks have to be reduced ‘as far as possible’, ‘to a minimum’, ‘to the lowest possible level’, ‘minimized’
or ‘removed’, according to the wording of the corresponding essential requirement.
NOTE 2 The manufacturer’s policy for determining acceptable risk must be in compliance with Essential
Requirements 1, 2, 5, 6, 7, 8, 9, 11 and 12 of the Directive.
NOTE 3 This Annex ZA is based on normative references according to the table of references in the European
foreword, replacing the references in the core text.
NOTE 4 When an Essential Requirement does not appear in Table ZA.1, it means that it is not addressed by this
document.
Table ZA.1 — Correspondence between this document and
Annex I of Directive 93/42/EEC [OJ L 169]
Essential Requirements Clause(s)/sub- Remarks/Notes
of Directive 93/42/EEC clause(s) of this
document
7.1 5.2, 5.3, 5.4, 5.5, 5.6 5.2 of the standard only meets the requirements
of Annex I, 7.1 of the Directive in respect of
toxicity and flammability.
5.3 of the standard only meets the requirements
of Annex I, 7.1 of the Directive in respect of
optical performance.
5.4 of the standard only meets the requirements
of Annex I, 7.1 of the Directive in respect of lens
thickness.
5.5 of the standard only meets the requirements
of Annex I, 7.1 of the Directive in respect of
positioning of the various lens segments.
5.6 of the standard only meets the requirements
of Annex I, 7.1 of the Directive in respect of the
orientation of polarizing lenses.
Essential Requirements Clause(s)/sub- Remarks/Notes
of Directive 93/42/EEC clause(s) of this
document
9.2 5.2 5.2 of the standard only meets the requirements
of Annex I, 9.2 of the Directive in respect of
mechanical strength and material ageing.
9.3 5.2 5.2 of the standard only meets the requirements
of Annex I, 9.3 of the Directive in respect of
flammability.
11.3.1 5.2 5.2 of the standard only meets the requirements
of Annex I, 11.3.1 of the Directive in respect of
transmittance.
13.1 Clause 7, Clause 9 Clause 7 of the standard only meets the
requirements of Annex I, 13.1 of the Directive in
respect of permanent or non-permanent marking.
Clause 9 of the standard only meets the
requirements of Annex I, 13.1 of the Directive in
respect of product identification.
13.3 Clause 9 Clause 9 of the standard only meets the
requirements of Annex I, 13.3 of the Directive in
respect of product trade name and manufacturer
address.
WARNING 1 — Presumption of conformity stays valid only as long as a reference to this document is
maintained in the list published in the Official Journal of the European Union. Users of this standard
should consult frequently the latest list published in the Official Journal of the European Union.
WARNING 2 — Other Union legislation may be applicable to the products falling within the scope of this
standard.
INTERNATIONAL ISO
STANDARD 21987
Second edition
2017-07
Ophthalmic optics — Mounted
spectacle lenses
Optique ophtalmique — Verres ophtalmiques montés
Reference number
ISO 21987:2017(E)
©
ISO 2017
ISO 21987:2017(E)
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

ISO 21987:2017(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Classification . 3
5 Requirements . 3
5.1 Reference temperature . 3
5.2 Lenses used in manufacturing complete spectacles . 3
5.3 Optical requirements . 3
5.3.1 General. 3
5.3.2 Back vertex power . 4
5.3.3 Direction of the cylinder axis . 4
5.3.4 Addition power or variation power. 5
5.3.5 Prism imbalance (relative prism error) for mounted single-vision lenses
(excluding position-specific single-vision lenses) and multifocal lenses . 5
5.3.6 Prism imbalance (relative prism error) for position-specific single-vision
lenses and power-variation lenses . 7
5.4 Requirements for thickness . 7
5.5 Requirements for positioning . 8
5.5.1 Multifocal lenses. 8
5.5.2 Position-specific single-vision lenses and power-variation lenses . 9
5.6 Orientation requirement for polarizing lenses . 9
6 Verification methods . 9
6.1 General . 9
6.2 Verification method for back vertex power. 9
6.3 Verification method for the direction of the cylinder axis. 9
6.4 Verification method for addition power or variation power .10
6.4.1 General.10
6.4.2 Method for verification of addition power for multifocal lenses .10
6.4.3 Method for verification of variation power (including addition power) for
power-variation lenses .10
6.5 Verification method for position and tilt .11
6.6 Verification method for prism imbalance (relative prism error) for mounted
single-vision lenses (excluding position-specific single-vision lenses) and
multifocal lenses .11
6.7 Verification method for planes of transmission of polarizing lenses.11
6.7.1 General.11
6.7.2 Apparatus .11
6.7.3 Procedure .12
6.8 Inspection method for material and surface quality .12
7 Marking for position-specific single-vision lenses and power-variation lenses .12
7.1 Permanent marking .12
7.2 Optional non-permanent marking .13
8 Recommendations on mounting .13
9 Identification .13
10 Reference to this document .13
Annex A (informative) Material and surface quality.14
Annex B (informative) Recommendations on mounting .15
ISO 21987:2017(E)
Annex C (informative) Alternative method for measuring prism imbalance (relative prism
error) for mounted single-vision lenses (excluding position-specific single-vision
lenses) and multifocal lenses .17
Bibliography .21
iv © ISO 2017 – All rights reserved

ISO 21987:2017(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 on 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 the following
URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee
SC 7, Ophthalmic optics and instruments.
This second edition cancels and replaces the first edition (ISO 21987:2009), which has been technically
revised.
INTERNATIONAL STANDARD ISO 21987:2017(E)
Ophthalmic optics — Mounted spectacle lenses
1 Scope
This document specifies requirements and test methods for mounted spectacle lenses relative to the
prescription order.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 7944, Optics and optical instruments — Reference wavelengths
ISO 8429, Optics and optical instruments — Ophthalmology — Graduated dial scale
ISO 8598-1, Optics and optical instruments — Focimeters — Part 1: General purpose instruments
ISO 8624, Ophthalmic optics — Spectacle frames — Measuring system and terminology
ISO 8980-1, Ophthalmic optics — Uncut finished spectacle lenses — Part 1: Specifications for single-vision
and multifocal lenses
ISO 8980-2, Ophthalmic optics — Uncut finished spectacle lenses — Part 2: Specifications for power-
variation lenses
ISO 13666, Ophthalmic optics — Spectacle lenses — Vocabulary
ISO 14889, Ophthalmic optics — Spectacle lenses — Fundamental requirements for uncut finished lenses
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 13666 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
power-variation lens
spectacle lens with a smooth variation of focal power over part or all of its area, without discontinuity,
designed to provide more than one focal power
Note 1 to entry: These are usually designed to provide increasing or decreasing spherical power, typically in a
vertical meridian, so as to provide correction for different object distances.
Note 2 to entry: Examples of power-variation lenses are, but not limited to, progressive-power lenses (3.2) and
degressive-power lenses (3.3).
ISO 21987:2017(E)
3.2
progressive-power lens
PPL
progressive-addition lens
PAL
varifocal lens
power-variation lens (3.1) with two reference points for focal power, generally designed to provide
correction for presbyopia and clear vision from distance to near
Note 1 to entry: Progressive-power lenses have a primary reference point (3.5) that is the distance reference point
and a secondary reference point (3.6) that is the near reference point.
3.3
degressive-power lens
power-variation lens (3.1) with a primary reference point (3.5) for near vision, generally designed to
provide clear vision from near to further distances
3.4
position-specific single-vision lens
single-vision lens, generally with complex surface geometry, that needs to be positioned accurately
according to the ordered specification and bears permanent alignment reference markings
Note 1 to entry: An example for position-specific single-vision lenses are those single-vision lenses calculated to
take into account the as-worn position and therefore requiring accurate mounting in front of the wearer’s eye.
3.5
primary reference point
point on the front surface of a power-variation lens (3.1) at which the verification power (3.8) for the
designed primary use of the lens applies
Note 1 to entry: All power-variation lenses have a primary reference point.
Note 2 to entry: For example, the primary reference point for a progressive-power lens (3.2) is the distance
reference point and for a degressive-power lens (3.3) is the near reference point.
3.6
secondary reference point
point on the front surface of a power-variation lens (3.1) at which the verification power (3.8) for the
designed secondary use of the lens applies
Note 1 to entry: Some power-variation lenses can have a secondary reference point (3.6) that is used for the
determination of the addition power or variation power (3.7).
Note 2 to entry: For example, the secondary reference point for a progressive-power lens (3.2) is the near
reference point.
3.7
variation power
difference between the vertex powers at the primary (3.5) and secondary
reference points (3.6)
Note 1 to entry: For example, for a progressive-power lens (3.2), this is the addition power, while for some
degressive-power lenses (3.3), it is the degression power.
Note 2 to entry: Variation power is defined for power-variation lenses (3.1) only if they have both a primary and a
secondary reference point.
2 © ISO 2017 – All rights reserved

ISO 21987:2017(E)
3.8
verification power
dioptric power of the lens, specifically calculated and provided by the manufacturer as the reference
for focimeter verification
Note 1 to entry: This is the power that is expected to be found as the measured power using the specified method,
and to which the tolerances apply.
Note 2 to entry: The verification power can differ from the ordered power, for example, because the ray path
through the lens when being measured on a focimeter can be different from that in the as-worn position, and
because of (ocular) physiological effects.
Note 3 to entry: If only one power is stated by manufacturer with the finished uncut or mounted lenses, then this
will be the ordered power and is to be used for verification.
4 Classification
Finished, mounted lenses are classified as follows:
a) single-vision finished lenses;
b) multifocal finished lenses;
c) power-variation finished lenses.
5 Requirements
5.1 Reference temperature
The tolerances shall apply at a temperature of 23 °C ± 5 °C.
5.2 Lenses used in manufacturing complete spectacles
Uncut finished lenses used in manufacturing complete spectacles shall meet the requirements of
ISO 14889.
Lenses in mounted spectacles shall also comply with those other requirements of the prescription
order not included in this document.
5.3 Optical requirements
5.3.1 General
The optical characteristics shall be verified using a focimeter conforming to the requirements
of ISO 8598-1.
The optical tolerances shall apply at the reference point(s) of the lenses at one of the reference
wavelengths specified in ISO 7944.
If the manufacturer states a verification power, then the ranges and tolerances in Table 1, Table 2
Table 3, and Table 4 shall be chosen according to and applied to the verification power. In this case, the
verification power may be stated by the manufacturer in an accompanying document.
ISO 21987:2017(E)
5.3.2 Back vertex power
When verified according to 5.3.1, spectacle lenses shall comply with the tolerances on the power of each
principal meridian (see Table 1, second column), and with the tolerances on the cylindrical power (see
Table 1, third to sixth column), using the method specified in 6.2:
— the back vertex power at the reference point of all single-vision lenses and the distance reference
point of multifocal lenses, including those with aspherical or atoroidal surfaces, shall comply with
the tolerances in Table 1;
— the back vertex power at the primary reference point of power-variation lenses shall comply with
the tolerances in Table 2.
Table 1 — Tolerances on the back vertex power of single-vision and multifocal lenses
Values in dioptres (D)
Tolerance on the Tolerance on the absolute cylindrical power
Power of principal
back vertex power
meridian with higher ab-
≥0,00 >0,75 >4,00
of each principal
>6,00
solute back vertex power
and ≤0,75 and ≤4,00 and ≤6,00
meridian
≥0,00 and ≤3,00 ±0,12 ±0,09 ±0,12 ±0,18 —
>3,00 and ≤6,00 ±0,12 ±0,12 ±0,12 ±0,18 ±0,25
>6,00 and ≤9,00 ±0,12 ±0,12 ±0,18 ±0,18 ±0,25
>9,00 and ≤12,00 ±0,18 ±0,12 ±0,18 ±0,25 ±0,25
>12,00 and ≤20,00 ±0,25 ±0,18 ±0,25 ±0,25 ±0,25
>20,00 ±0,37 ±0,25 ±0,25 ±0,37 ±0,37
Table 2 — Tolerances on the back vertex power at the primary reference point of power-
variation lenses
Values in dioptres (D)
Tolerance on the Tolerance on the absolute cylindrical power
Power of principal
back vertex power
meridian with higher ab-
≥0,00 >0,75 >4,00
of each principal
>6,00
solute back vertex power
and ≤0,75 and ≤4,00 and ≤6,00
meridian
≥0,00 and ≤6,00 ±0,12 ±0,12 ±0,18 ±0,18 ±0,25
>6,00 and ≤9,00 ±0,18 ±0,18 ±0,18 ±0,18 ±0,25
>9,00 and ≤12,00 ±0,18 ±0,18 ±0,18 ±0,25 ±0,25
>12,00 and ≤20,00 ±0,25 ±0,18 ±0,25 ±0,25 ±0,25
>20,00 ±0,37 ±0,25 ±0,25 ±0,37 ±0,37
5.3.3 Direction of the cylinder axis
When verified according to 5.3.1 and using the method specified in 6.3, the direction of the cylinder axis
shall comply with the tolerances specified in Table 3. The cylinder axis shall be specified in accordance
with ISO 8429.
NOTE 1 To allow for some tolerance in mounting, the tolerances on the direction of cylinder axis have generally
been increased over the tolerances found in ISO 8980-1 and ISO 8980-2.
NOTE 2 There are no requirements for the axis direction for cylindrical powers of less than 0,12 D.
4 © ISO 2017 – All rights reserved

ISO 21987:2017(E)
Table 3 — Tolerances on the direction of the cylinder axis
Absolute
≥0,12 >0,25 >0,50 >0,75 >1,50
cylindrical
<0,12 and and and and and >2,50
power
≤0,25 ≤0,50 ≤0,75 ≤1,50 ≤2,50
dioptres (D)
Tolerance on the
direction of the
No
±16 ±9 ±6 ±4 ±3 ±2
cylinder axis
requirement
degrees (°)
5.3.4 Addition power or variation power
For multifocal lenses and those power-variation lenses with primary and secondary reference points,
the following shall apply. When verified according to 5.3.1 and using the method specified in 6.4, the
addition or variation p
...