EN ISO 9342-1:2023
(Main)Optics and optical instruments - Test lenses for calibration of focimeters - Part 1: Reference lenses for focimeters used for measuring spectacle lenses (ISO 9342-1:2023)
Optics and optical instruments - Test lenses for calibration of focimeters - Part 1: Reference lenses for focimeters used for measuring spectacle lenses (ISO 9342-1:2023)
This document specifies requirements for reference lenses for the calibration and verification of focimeters that are used for the measurement of spectacle form lenses, e.g. those complying with ISO 8598-1. It also gives a method for the determination of the back vertex power of the reference lenses.
NOTE It is accepted that other reference lenses can also be used with powers within the given range, manufactured to the same standard of accuracy and form, but different back vertex powers. However, only lenses with integer nominal powers, as described in 4.1, can be used for the calibration of digitally-rounding focimeters.
Optik und optische Instrumente - Prüfgläser zur Kalibrierung von Scheitelbrechwert-Messgeräten - Teil 1: Referenzgläser für Scheitelbrechwert-Messgeräte für die Messung von Brillengläsern (ISO 9342‑1:2023)
Dieses Dokument legt Anforderungen an Referenzgläser zur Kalibrierung und Überprüfung von Scheitelbrechwert-Messgeräten fest, die für die Messung von Brillengläsern verwendet werden, z. B. solche, die der ISO 8598 1 entsprechen. Es enthält auch ein Verfahren zur Bestimmung des bildseitigen Scheitelbrechwerts der Referenzgläser.
ANMERKUNG Die Verwendung anderer Referenzgläser, deren Brechwert im angegebenen Bereich liegt und die bezüglich Genauigkeit und Form gleichwertig gefertigt wurden, jedoch andere bildseitige Scheitelbrechwerte aufweisen, ist ebenfalls zulässig. Für die Kalibrierung von digital rundenden Scheitelbrechwert-Messgeräten können jedoch nur Gläser mit einem ganzzahligen Sollscheitelbrechwert, wie in 4.1 beschrieben, verwendet werden.
Optique et instruments d'optique - Verres étalons pour l'étalonnage des frontofocomètres - Partie 1: Verres de référence pour frontofocomètres pour le mesurage des verres de lunettes (ISO 9342-1:2023)
Le présent document spécifie les exigences applicables aux verres de référence pour l'étalonnage et la vérification des frontofocomètres utilisés pour le mesurage des verres de lunettes, par exemple ceux qui sont conformes à l'ISO 8598-1. Il donne en outre une méthode qui permet de déterminer la puissance frontale arrière des verres de référence.
NOTE Il est admis que d'autres verres de référence ayant des puissances situées dans la plage donnée, fabriqués selon les mêmes normes d'exactitude et de courbure, mais ayant des puissances frontales arrière différentes, puissent être utilisés. Cependant, pour l'étalonnage des frontofocomètres à affichage numérique avec arrondi, on ne peut utiliser que des verres ayant des puissances nominales entières, comme décrit en 4.1.
Optika in optični instrumenti - Preskusne leče za umerjanje fokometrov – 1. del: Referenčne leče za fokometre, ki se uporabljajo za merjenje spektralnih leč (ISO 9342-1:2023)
Ta dokument določa zahteve za referenčne leče za umerjanje in preverjanje fokometrov, ki se uporabljajo za merjenje spektralnih leč, npr. tistih, ki so skladne s standardom ISO 8598-1. Prav tako podaja metodo za določanje moči referenčnih leč glede na vrh na zadnji strani.
OPOMBA: Sprejemljivo je, da se lahko uporabljajo tudi druge referenčne leče z močmi znotraj danega območja, ki so izdelane po enakem standardu natančnosti in oblike, vendar z različnimi močmi glede na vrh na zadnji strani. Vendar pa se lahko za umerjanje fokometrov z digitalnim zaokroževanjem uporabljajo le leče s celimi nazivnimi močmi, kot je opisano v točki 4.1.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-2023
Nadomešča:
SIST EN ISO 9342-1:2005
Optika in optični instrumenti - Preskusne leče za umerjanje fokometrov – 1. del:
Referenčne leče za fokometre, ki se uporabljajo za merjenje spektralnih leč (ISO
9342-1:2023)
Optics and optical instruments - Test lenses for calibration of focimeters - Part 1:
Reference lenses for focimeters used for measuring spectacle lenses (ISO 9342-1:2023)
Optik und optische Instrumente - Prüfgläser zur Kalibrierung von Scheitelbrechwert-
Messgeräten - Teil 1: Referenzgläser für Scheitelbrechwert-Messgeräte für die Messung
von Brillengläsern (ISO 9342-1:2023)
Optique et instruments d'optique - Verres étalons pour l'étalonnage des frontofocomètres
- Partie 1: Verres de référence pour frontofocomètres pour le mesurage des verres de
lunettes (ISO 9342-1:2023)
Ta slovenski standard je istoveten z: EN ISO 9342-1:2023
ICS:
11.040.70 Oftalmološka oprema Ophthalmic equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 9342-1
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2023
EUROPÄISCHE NORM
ICS 11.040.70 Supersedes EN ISO 9342-1:2005
English Version
Optics and optical instruments - Test lenses for calibration
of focimeters - Part 1: Reference lenses for focimeters used
for measuring spectacle lenses (ISO 9342-1:2023)
Optique et instruments d'optique - Verres étalons pour Optik und optische Instrumente - Prüfgläser zur
l'étalonnage des frontofocomètres - Partie 1: Verres de Kalibrierung von Scheitelbrechwert-Messgeräten - Teil
référence pour frontofocomètres pour le mesurage des 1: Referenzgläser für Scheitelbrechwert-Messgeräte
verres de lunettes (ISO 9342-1:2023) für die Messung von Brillengläsern (ISO 9342-1:2023)
This European Standard was approved by CEN on 7 July 2023.
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, Türkiye 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
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9342-1:2023 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 9342-1:2023) 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 2024, and conflicting national standards shall
be withdrawn at the latest by January 2024.
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 9342-1:2005.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 9342-1:2023 has been approved by CEN as EN ISO 9342-1:2023 without any
modification.
INTERNATIONAL ISO
STANDARD 9342-1
Second edition
2023-07
Optics and optical instruments — Test
lenses for calibration of focimeters —
Part 1:
Reference lenses for focimeters used
for measuring spectacle lenses
Optique et instruments d'optique — Verres étalons pour l'étalonnage
des frontofocomètres —
Partie 1: Verres de référence pour frontofocomètres pour le mesurage
des verres de lunettes
Reference number
ISO 9342-1:2023(E)
ISO 9342-1:2023(E)
© ISO 2023
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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 9342-1:2023(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Design requirements and recommendations for reference lenses .3
4.1 General . 3
4.2 Spherical reference lenses . 3
4.2.1 Standard spherical reference lenses . 3
4.2.2 Low power spherical reference lenses (optional) . 4
4.3 Prismatic reference lenses . 5
4.4 Cylindrical reference lens . 5
4.5 Spherocylindrical-power reference lens . 6
4.6 Reference filter . 7
4.7 Darker reference filters (optional) . 7
Annex A (informative) Design of spherical reference lenses . 9
Annex B (informative) Design and/or validation of prismatic reference lenses .14
Annex C (informative) Verification of the cylindrical reference lens .17
Bibliography .19
iii
ISO 9342-1:2023(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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
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 second edition cancels and replaces the first edition (ISO 9342-1:2005), which has been technically
revised.
The main changes are as follows:
— use of the term "reference lens" to denote these high precision test lenses;
— use of the term "verified power" instead of "conventional power";
— the addition of the spherocylindrical-power reference lens and, with some modification to tolerances,
reference filters that were added to ISO 8598-1 during its last revision;
— the optional addition of low power spherical reference lenses;
— editorial revision and clarification of Annex A on the design of reference spherical lenses
— the addition of annexes on the design and validation of prismatic reference lenses and the validation
of the cylindrical reference lens.
A list of all parts in the ISO 9342 series can be found on the ISO website.
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
INTERNATIONAL STANDARD ISO 9342-1:2023(E)
Optics and optical instruments — Test lenses for
calibration of focimeters —
Part 1:
Reference lenses for focimeters used for measuring
spectacle lenses
1 Scope
This document specifies requirements for reference lenses for the calibration and verification of
focimeters that are used for the measurement of spectacle form lenses, e.g. those complying with
ISO 8598-1. It also gives a method for the determination of the back vertex power of the reference lenses.
NOTE It is accepted that other reference lenses can also be used with powers within the given range,
manufactured to the same standard of accuracy and form, but different back vertex powers. However, only lenses
with integer nominal powers, as described in 4.1, can be used for the calibration of digitally-rounding focimeters.
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 13666, Ophthalmic optics — Spectacle lenses — Vocabulary
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 terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
back vertex power
reciprocal of the paraxial vertex focal length
Note 1 to entry: According to ophthalmic convention, the “power” of a lens is specified as the back vertex power.
-1
Note 2 to entry: The unit for expressing focal length is the metre and for vertex power is the reciprocal metre (m ).
The name for this unit is “dioptre”, and the symbol is “D”.
[SOURCE: ISO 13666:2019, 3.10.8, modified — A Note 2 to entry was added.]
3.2
reference lens
lens complying with the requirements of this document used for the calibration and verification of
focimeters
ISO 9342-1:2023(E)
3.3
spherical reference lens
lens with spherical front and back surfaces used for the calibration and verification of dioptric power
measurements by focimeters
Note 1 to entry: A plane surface is a special case of a spherical surface having an infinite radius of curvature and
hence of zero power.
3.4
prismatic reference lens
prismatic lens constructed with two non-parallel plane surfaces used for the calibration and verification
of prismatic power measurements by focimeters
Note 1 to entry: The unit for expressing prismatic power is centimetres deviation per metre distance (cm/m).
The name for this unit is “prism dioptre” and the symbol is “Δ”.
Note 2 to entry: The prism shall be constructed to give the correct deviation with light incident perpendicular to
one surface.
3.5
cylindrical reference lens
lens with one plane surface and one cylindrical surface used to calibrate and verify the axis indicator
and axis marker with reference to the orientation of the adjusting rail
3.6
spherocylindrical-power reference lens
lens with one spherical surface and one toroidal surface used to check the non-symmetric cylindrical
power and non-symmetric cylinder axis error given by an automated focimeter after calibration
3.7
reference filter
neutral density filter of plano power used to check the capability of an automated focimeter to measure
tinted lenses
3.8
surface power
local ability of a finished surface to change the vergence of a bundle of rays incident at the surface
Note 1 to entry: The surface power is determined from the radius or radii of the surface and the refractive index
of the optical material, and is calculated for light incident or emergent in air. The refractive index may be the
actual refractive index of the material or a nominal value.
Note 2 to entry: Back surface power is given by the following formula:
F = (1 – n)/r
BS 2
where
-1
F is the back surface power in D (m );
BS
n is the refractive index of the material of the lens;
r is the radius of curvature of the back surface in metres, regarded as being positive if the centre of
curvature is behind the surface according to the direction of travel of light through the surface.
[SOURCE: ISO 13666:2019, 3.10.4, modified — Note 2 to entry was added.]
ISO 9342-1:2023(E)
3.9
verified power
power derived from measurements of a set of parameters of the reference lens (3.2)
Note 1 to entry: Each verified power comes with an uncertainty. This uncertainty is derived from the uncertainties
of the individual measurements used to establish the verified power and should be within the values specified in
this document.
Note 2 to entry: An example for the set of parameters to be measured for a spherical reference lens are the
refractive index, radii of curvature of the two surfaces and thickness (see Annex A). For a prismatic reference
lens, an example for a set of parameters to be measured are the refractive index and its apical angle (i.e. the angle
between its two surfaces); (see Annex B).
Note 3 to entry: These parameters are measured using procedures and/or equipment traceable to certificates
issued by an appropriate metrology laboratory.
4 Design requirements and recommendations for reference lenses
4.1 General
All reference lenses shall be made of homogeneous white crown glass selected to be free of bubbles and
striae in an area of 8 mm radius surrounding the centre of the aperture.
Other materials may also be used provided their use results in lenses with a durability and optical
reproducibility within the given tolerance over time and that can be manufactured to the same standard
of uncertainty and form as the glass lenses specified in this document.
The reference wavelength for the reference lenses used to calibrate and calculate the verified power
value of the back vertex power shall be stated. The reference wavelengths shall be either the green
mercury e-line (λ = 546,07 nm) or the yellow helium d-line (λ = 587,56 nm), in accordance with
e d
ISO 7944.
The actual powers of the reference lenses should be close to, but need not be not exactly, the nominal
power. The verified power (see 3.9) is that used to calibrate instruments. The closer the verified powers
are to integral values, the easier it will be to calibrate or verify the calibration of some types of focimeter,
e.g. manual focusing instruments or automated instruments that have display steps of 0,25 D.
The verified power of a reference lens is defined as a calculated value, which is based on actual
measurements of the individual design parameters of the reference lens, such as refractive index, radius
of curvature of lens surface, etc. These are measured using procedures and/or equipment traceable to
certificates issued by an appropriate metrology laboratory. An appropriate metrology laboratory may
be one accredited to ISO/IEC 17025 for these measurements or one specified in national or regional
regulations.
The reference lenses are recommended to have protective mounts designed so that, when a lens is
correctly placed on the lens support, the focimeter is not obstructed. It is also recommended that the
verified power of the lens and the reference wavelength be marked on the mount.
4.2 Spherical reference lenses
4.2.1 Standard spherical reference lenses
For a complete set of spherical reference lenses, the following set of nominal back vertex powers is
recommended:
−25 D, −20 D, −15 D, −10 D, −5 D, +5 D, +10 D, +15 D, +20 D, +25 D
The spherical reference lenses should have an aperture of at least 15 mm.
ISO 9342-1:2023(E)
In order to minimize the influence of spherical aberration, the curvature of the back surface and the
centre thickness shall approximately correspond to those of normal spectacle lenses. Table 1 gives
nominal back surface powers and ranges for centre thickness, which will ensure that the reference
lenses are of this form.
The highest permissible uncertainties on the verified spherical power for the standard spherical
reference lenses are also specified in Table 1.
Table 1 — Design range for the standard spherical reference lenses
Highest permissible un-
Nominal back vertex Range for back surface Range for centre thick-
certainty on the verified
a
power power ness
spherical power
D D mm D
−25 −26 to −24 2 to 6 ±0,03
−20 −21 to −19 2 to 6 ±0,02
−15 −16 to −14 2 to 6 ±0,02
−10 −13 to −11 2 to 8 ±0,01
−5 −10 to −8 2 to 8 ±0,01
+5 −6 to −4 3 to 7 ±0,01
+10 −4 to −2 3 to 7 ±0,02
b
+15 −2 to 0 5 to 7 ±0,02
b
+20 −1 to 0 7 to 9 ±0,03
b
+25 −1 to 0 9 to 11 ±0,04
a
These centre thicknesses are required to guarantee stability in the negative power range.
b
The back surface shall not be convex.
NOTE 1 In Annex A, an example is given for the design of reference lenses that meet the requirements
of Tables 1 for apertures of up to 15 mm diameter.
NOTE 2 The astigmatic power can be assessed the same way as uncertainties in spherical power by measuring
surface geometries. See Annex A.
4.2.2 Low power spherical reference lenses (optional)
When validating automated instruments, it is recommended to add extra low powers into the range.
Suggested values can be found in Table 2. The highest permissible uncertainties on the verified spherical
power for these reference lenses are also specified in Table 2.
Table 2 — Design range for the low power spherical reference lenses
Highest permissible un-
Nominal back vertex Range for back surface Range for centre thick-
certainty on the verified
a
power power ness
spherical power
D D mm D
–2,5 −8 to −6
b
–0,25 −7 to −5
b
–0,12 −7 to −5
2 to 8 ±0,01
b
+0,12 −7 to -5
b
+0,25 −7 to −5
+2,5 −7 to −5
a
These centre thicknesses are required to guarantee stability.
b
Choose either +0,25 and −0,25 or +0,12 and −0,12.
ISO 9342-1:2023(E)
NOTE 1 In Annex A,
...
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