prEN ISO 9342-1

Optics and optical instruments - Test lenses for calibration of focimeters - Part 1: Reference lenses for focimeters used for measuring spectacle lenses (ISO/DIS 9342-1:2022)

Optik und optische Instrumente - Prüfgläser zur Kalibrierung von Scheitelbrechwert-Messgeräten - Teil 1: Referenzgläser für Scheitelbrechwert-Messgeräte für die Messung von Brillengläsern (ISO/DIS 9342‑1:2022)

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/DIS 9342-1:2022)

Optika in optični instrumenti - Preskusne leče za umerjanje fokometrov – 1. del: Referenčne leče za fokometre, ki se uporabljajo za merjenje spektralnih leč (ISO/DIS 9342-1:2022)

General Information

• Status: Not Published
• Publication Date: 08-Jan-2024
• ICS: 11.040.70 - Ophthalmic equipment
• Technical Committee: CEN/TC 170 - Ophthalmic optics
• Drafting Committee: CEN/TC 170 - Ophthalmic optics
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 02-Feb-2023
• Completion Date: 02-Feb-2023
• Ref Project: oSIST prEN ISO 9342-1:2022 - Optics and optical instruments - Test lenses for calibration of focimeters - Part 1: Reference lenses for focimeters used for measuring spectacle lenses (ISO/DIS 9342-1:2022)

Relations

• Revises: EN ISO 9342-1:2005 - Optics and optical instruments - Test lenses for calibration of focimeters - Part 1: Test lenses for focimeters used for measuring spectacle lenses (ISO 9342-1:2005)
• Effective Date: 04-Dec-2019

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN ISO 9342-1:2022
01-september-2022
Optika in optični instrumenti - Preskusne leče za umerjanje fokometrov – 1. del:
Referenčne leče za fokometre, ki se uporabljajo za merjenje spektralnih leč
(ISO/DIS 9342-1:2022)

Optics and optical instruments - Test lenses for calibration of focimeters - Part 1:

Reference lenses for focimeters used for measuring spectacle lenses (ISO/DIS 9342-

1:2022)

Optik und optische Instrumente - Prüfgläser zur Kalibrierung von Scheitelbrechwert-

Messgeräten - Teil 1: Referenzgläser für Scheitelbrechwert-Messgeräte für die Messung

von Brillengläsern (ISO/DIS 9342‑1:2022)

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/DIS 9342-1:2022)
Ta slovenski standard je istoveten z: prEN ISO 9342-1
ICS:
11.040.70 Oftalmološka oprema Ophthalmic equipment
oSIST prEN ISO 9342-1:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 9342-1:2022
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oSIST prEN ISO 9342-1:2022
DRAFT INTERNATIONAL STANDARD
ISO/DIS 9342-1
ISO/TC 172/SC 7 Secretariat: DIN
Voting begins on: Voting terminates on:
2022-06-10 2022-09-02
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 étalons pour frontofocomètres pour le mesurage des verres de lunettes

ICS: 11.040.70
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 9342-1:2022(E)
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 SUPPORTING DOCUMENTATION. © ISO 2022
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oSIST prEN ISO 9342-1:2022
ISO/DIS 9342-1:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

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

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Published in Switzerland
© ISO 2022 – All rights reserved
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oSIST prEN ISO 9342-1:2022
ISO/DIS 9342-1:2022(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 reference lenses .......................................................................................................................................... 3

4.2.2 Low power reference lenses (optional) .......................................................................................................... 4

4.3 Prismatic reference lenses ........................................................................................................................................................... 4

4.4 Cylindrical reference lenses........................................................................................................................................................ 5

4.5 Spherocylindrical-power reference lenses .................................................................................................................... 5

4.6 Reference filter ....................................................................................................................................................................................... 6

4.7 Darker reference filters (optional) ....................................................................................................................................... 6

5 Uncertainties and Tolerances ................................................................................................................................................................ 7

5.1 Uncertainties for spherical reference lenses ............................................................................................................... 7

5.2 Uncertainties for prismatic reference lenses .............................................................................................................. 8

5.3 Tolerance for the axis of the cylindrical reference lens ..................................................................................... 8

Annex A (informative) Design of spherical reference lenses .................................................................................................... 9

Annex B (informative) Design and/or validation of prismatic reference lenses ...............................................13

Annex C (informative) Verification of the cylindrical reference lens ...........................................................................16

iii
© ISO 2022 – All rights reserved
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oSIST prEN ISO 9342-1:2022
ISO/DIS 9342-1:2022(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: 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.

This second edition cancels and replaces the first edition (ISO 9342-1:2005), which has been technically

revised.
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.
© ISO 2022 – All rights reserved
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oSIST prEN ISO 9342-1:2022
DRAFT INTERNATIONAL STANDARD ISO/DIS 9342-1:2022(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 part of ISO 9342 specifies requirements for reference lenses for the calibration and verification of

focimeters that are used for the measurement of spectacle form lenses. 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 paragraph 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 8598-1, Optics and optical instruments — Focimeters — Part 1: General purpose instruments

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 as well as the following

apply.

ISO and IEC maintain terminological 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 value of the back vertex focal length

Note 1 to entry: According to ophthalmic convention, the “power” of a lens is specified as the back vertex power.

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 by adding note 2 to entry.]
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ISO/DIS 9342-1:2022(E)
3.2
reference lens

lens complying with this document used for the calibration and verification of focimeters

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 surface of plano power is a special case of a spherical surface having an infinite radius of

curvature.
3.4
prismatic reference lens

prismatic lens constructed with two 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 that are used to check the non-symmetric

cylinder power and cylinder axis error given by an automated focimeter after calibration

3.7
reference filter

neutral density filter of plano power that is used to check the capability of an automated focimeter to

measure tinted lenses
3.8
surface power

capacity of an optical surface to change the curvature of incident wavefronts by refraction

Note 1 to entry: Back surface power is given by the formula:
F = (1 – n)/r
BS 2
where
F is the back surface power in D;
n is the refractive index of the material of the lens, and

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, 3.2.10, modified by the deletion of 'of a lens' and 'or deviation' and the

addition of Note 1 to entry.]
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oSIST prEN ISO 9342-1:2022
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3.9
verified power

power derived from measurements of the parameters of the reference lens

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 must 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 4 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 above.

The reference wavelength for the reference lenses used to calibrate and calculate the conventional

power value of the back vertex power shall be stated. The reference wavelengths shall be either the

green mercury e line (λe = 546,07 nm) or the yellow helium d-line (λd = 587,56 nm).

The conventional power value 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 17025 for these measurements or one specified in national or

regional regulations.

NOTE The reference lenses should have protective mounts, which are designed so that, when a lens is

correctly placed on the lens support, the focimeter is not obstructed. It is recommended that the verified power

value of the power of the lens and the reference wavelength be marked on the mount.

4.2 Spherical reference lenses
4.2.1 Standard 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.

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.
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oSIST prEN ISO 9342-1:2022
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Table 1 — Design range for the standard spherical reference lenses
Range for back surface
Nominal back vertex power Range for centre thickness
power
D D mm
−25 -26 to -24 2 to 6
−20 -21 to -19 2 to 6
−15 -16 to -14 2 to 6
−10 -13 to -11 2 to 8
−5 -10 to -8 2 to 8
+5 -6 to -4 3 to 7
+10 -4 to -2 3 to 7
+15 -2 to 0 5 to 7
+20 -1 to 0 7 to 9
+25 -1 to 0 9 to 11

The centre thicknesses are required to guarantee stability in the negative power range.

The back surface shall not be convex
4.2.2 Low power 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.
Table 2 — Design range for the low power spherical reference lenses

Nominal back vertex Nominal back surface Power range for back Range for centre thick-

power power surface power ness
D D D mm
–2,5
–0,25
–0,12
–6 ± 1 2 to 8
+0,12
+0,25
+2,5

The centre thicknesses are required to guarantee stability in the negative power range.

Choose either +0,25 and-0,25 or +0,12 and -0,12.
4.3 Prismatic reference lenses

The optical surfaces of prismatic reference lenses shall be plane and their aperture shall be at least

15 mm.

The number of prismatic reference lenses that should be used to adjust or to check a focimeter depends

on the measuring range of the instrument. The prismatic power marked on the mount shall be the

power for light incident normal to the surface resting on the lens support.
For a complete set, the following set of prismatic powers is recommended:
2 Δ 5 Δ 10 Δ 15 Δ 20 Δ

NOTE The prismatic value may depend on the design of the focimeter (IOA or FOA – see ISO 13666) due to

the implications of incident angle. This is explained in ISO/TR 29890.
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oSIST prEN ISO 9342-1:2022
ISO/DIS 9342-1:2022(E)
4.4 Cylindrical reference lenses

This reference lens shall be a positive plano-cylindrical lens of at least 5 D edged to a rectangular shape

and shall have the dimensions, nominal unless otherwise stated, shown in Figure 1. The cylinder axis

shall be parallel to the longer, reference, side of the rectangle and shall be marked by a centre line. The

reference side shall also be marked.
Dimensions in millimetres
Key
1 Centre line
2 Reference side/edge
Figure 1 — Cylindrical reference lens
4.5 Spherocylindrical-power reference lenses

Spherocylindrical-power reference lenses are used to test automated focimeters that measure sphere

power, cylinder power, and cylinder axis simultaneously for non-symmetric cylinder power and cylinder

axis errors. They are specially mounted spherocylindrical-power lenses with a power of –2,00 D sph/–

1,50 D cyl, of spectacle form and quality conforming to ISO 8980-1, and shall have a diameter of not less

than 25 mm.

The spherocylindrical-power reference lens is centred and firmly affixed on to an octagonal disk so

that the optical centre of the lens is coincident with the geometrical centre of the disk. The length of

the sides of the disk shall be between 25 mm and 30 mm. The axis of the cylinder should be aligned

as close as practicable to one of the faces of the disk. The disk shall have a clear central aperture of at

least 10 mm diameter centred on the geometrical centre of the disk. The disk is constructed of metal or

rigid plastic at least 3 mm in thickness.

An illustration of the specially mounted spherocylindrical-power reference lens with the disk is shown

in Figure 2.

As an alternative to using a lens mounted on an octagonal disc, a lens may be edged to the same

octago
...