prEN ISO 8980-3

Ophthalmic optics - Uncut finished spectacle lenses - Part 3: Transmittance specifications and test methods (ISO/DIS 8980-3:2021)

Augenoptik - Rohkantige fertige Brillengläser - Teil 3: Transmissionsanforderungen und Prüfverfahren (ISO/DIS 8980-3:2021)

Optique ophtalmique - Verres de lunettes finis non détourés - Partie 3: Spécifications relatives au facteur de transmission et méthodes d'essai (ISO/DIS 8980-3:2021)

Očesna optika - Nebrušena zglajena stekla očal - 3. del: Specifikacije za prepustnost in preskusne metode (ISO/DIS 8980-3:2021)

General Information

• Status: Not Published
• ICS: 11.040.70 - Ophthalmic equipment
• Technical Committee: CEN/TC 170 - Ophthalmic optics
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Due Date: 03-Mar-2022
• Completion Date: 03-Mar-2022
• Ref Project: oSIST prEN ISO 8980-3:2021 - Ophthalmic optics - Uncut finished spectacle lenses - Part 3: Transmittance specifications and test methods (ISO/DIS 8980-3:2021)

RELATIONS

• Revised: EN ISO 8980-3:2013 - Ophthalmic optics - Uncut finished spectacle lenses - Part 3: Transmittance specifications and test methods (ISO 8980-3:2013)
• Effective Date: 30-May-2018

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN ISO 8980-3:2021
01-april-2021
Očesna optika - Nebrušena zglajena stekla očal - 3. del: Specifikacije za
prepustnost in preskusne metode (ISO/DIS 8980-3:2021)
Ophthalmic optics - Uncut finished spectacle lenses - Part 3: Transmittance
specifications and test methods (ISO/DIS 8980-3:2021)

Augenoptik - Rohkantige fertige Brillengläser - Teil 3: Transmissionsanforderungen und

Prüfverfahren (ISO/DIS 8980-3:2021)

Optique ophtalmique - Verres de lunettes finis non détourés - Partie 3: Spécifications

relatives au facteur de transmission et méthodes d'essai (ISO/DIS 8980-3:2021)
Ta slovenski standard je istoveten z: prEN ISO 8980-3
ICS:
11.040.70 Oftalmološka oprema Ophthalmic equipment
oSIST prEN ISO 8980-3:2021 en,fr,de

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

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oSIST prEN ISO 8980-3:2021
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oSIST prEN ISO 8980-3:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 8980-3
ISO/TC 172/SC 7 Secretariat: DIN
Voting begins on: Voting terminates on:
2021-02-23 2021-05-18
Ophthalmic optics — Uncut finished spectacle lenses —
Part 3:
Transmittance specifications and test methods
Optique ophtalmique — Verres de lunettes finis non détourés —

Partie 3: Spécifications relatives au facteur de transmission et méthodes d'essai

ICS: 11.040.70
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
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 8980-3:2021(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 2021
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oSIST prEN ISO 8980-3:2021
ISO/DIS 8980-3:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

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Published in Switzerland
ii © ISO 2021 – All rights reserved
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oSIST prEN ISO 8980-3:2021
ISO/DIS 8980-3:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols .......................................................................................................................................................................................................................... 2

5 Classification ............................................................................................................................................................................................................ 2

6 Requirements .......................................................................................................................................................................................................... 2

6.1 General ........................................................................................................................................................................................................... 2

6.2 General transmittance requirements .................................................................................................................................. 2

6.2.1 Tint descriptions, categories, and UV transmittance requirements.................................... 2

6.2.2 Tolerances on luminous transmittance of tinted lenses ................................................................ 3

6.3 Spectral transmittance requirements of spectacle lenses intended for driving and

road use ......................................................................................................................................................................................................... 3

6.3.1 General...................................................................................................................................................................................... 3

6.3.2 Spectral transmittance ........................................................................................................................................... ..... 4

6.3.3 Daylight use .......................................................................................................................................................................... 4

6.3.4 Driving in twilight or at night ............................................................................................................................... 4

6.3.5 Relative visual attenuation coefficient (quotient) for incandescent traffic

signal light detection .................................................................................................................................................... 4

6.4 Additional transmittance requirements for special types of spectacle lenses ................................ 4

6.4.1 Photochromic spectacle lenses............................................................................................................................ 4

6.4.2 Polarizing spectacle lenses ..................................................................................................................................... 5

6.4.3 Gradient-tinted spectacle lenses ........................................................................................................................ 5

6.5 Resistance to ultraviolet radiation ......................................................................................................................................... 6

7 Test methods ............................................................................................................................................................................................................. 6

7.1 General ........................................................................................................................................................................................................... 6

7.2 Spectral transmittance ..................................................................................................................................................................... 6

7.3 Luminous transmittance and relative visual attenuation coefficient (quotient) ......... .................. 6

7.4 Ultraviolet transmittance ............................................................................................................................................................... 7

7.4.1 Principle .................................................................................................................................................................................. 7

7.4.2 Apparatus ............................................................................................................................................................................... 7

7.4.3 Calculation ............................................................................................................................................................................. 7

7.5 Transmittance properties of photochromic spectacle lenses and photochromic

specimens .................................................................................................................................................................................................... 7

7.5.1 Test lenses ............................................................................................................................................................................. 7

7.5.2 Apparatus ............................................................................................................................................................................... 7

7.5.3 Determination of transmittance ......................................................................................................................10

7.6 Test methods for polarizing spectacle lenses ............................................................................................................11

7.6.1 Mean luminous transmittance ..........................................................................................................................11

7.6.2 Polarizing efficiency ...................................................................................................................................................11

7.6.3 Plane of transmission ...............................................................................................................................................11

7.7 Determination of resistance to radiation ......................................................................................................................12

7.7.1 Principle ...............................................................................................................................................................................12

7.7.2 Reference apparatus ..................................................................................................................................................13

7.7.3 Procedure using reference apparatus ........................................................................................................13

8 Identification .........................................................................................................................................................................................................13

Annex A (normative) Spectral data for calculating relative visual attenuation quotients for

incandescent signal lights ........................................................................................................................................................................15

Annex B (normative) Calculation of solar UV transmittance values ................................................................................20

Annex C (normative) Cut-on filter for UV filtering ..............................................................................................................................22

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Annex D (informative) Spectral radiation risks .....................................................................................................................................25

Annex E (informative) Transmittance equations in summation form ...........................................................................26

Annex F (informative) Example of the calculation of luminous transmittance, τ ............................................30

Bibliography .............................................................................................................................................................................................................................32

iv © ISO 2021 – All rights reserved
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oSIST prEN ISO 8980-3:2021
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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.

The committee responsible for this document is ISO/TC 172, Optics and photonics, Subcommittee SC 7,

Ophthalmic optics and instruments.

This fourth edition cancels and replaces the third edition (ISO 8980-3:2013), which has been technically

revised.
A list of all parts in the ISO 8980 series can be found on the ISO website.
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oSIST prEN ISO 8980-3:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 8980-3:2021(E)
Ophthalmic optics — Uncut finished spectacle lenses —
Part 3:
Transmittance specifications and test methods
1 Scope

This part of ISO 8980 specifies requirements for the transmittance properties of uncut and unmounted

finished spectacle lenses, including attenuation of solar radiation.
This part of ISO 8980 is not applicable to

— spectacle lenses having specific transmittance or absorption characteristics prescribed for medical

reasons;

— products to which specific personal protective equipment transmittance standards apply;

— products intended for direct observation of the sun, such as for solar-eclipse viewing.

NOTE 1 By reference to ISO 21987 and ISO 14889, this document also applies to lenses mounted in spectacles.

NOTE 2 Optical and geometric requirements are specified for uncut finished spectacle lenses in ISO 8980-1

and ISO 8980-2, and for mounted lenses, in ISO 21987.
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 11664-1, 2019, Colorimetry — Part 1: CIE standard colorimetric observers
ISO 11664-2, Colorimetry — Part 2: CIE standard illuminants
ISO 13666:2019, Ophthalmic optics — Spectacle lenses — Vocabulary

ISO 14889:2013+A1 2017, Ophthalmic optics — Spectacle lenses — Fundamental requirements for uncut

finished lenses

ISO 18526-2:2020, Eye and face protection — Test methods — Part 2: Physical optical properties

ISO/IEC Guide 98-3:2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in

measurement (GUM: 1995)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 13666 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 http:// www .electropedia .org/

Note 1 to entry For the convenience of the reader, equations are presented in Annex F in summation form.

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4 Symbols

The symbols for the characteristic luminous transmittances of photochromic lenses are given in Table 1.

Table 1 — Symbols for the characteristic luminous transmittances of photochromic lenses

Symbols Characteristic luminous transmittances

τ Luminous transmittance in the faded state as reached at (23 ± 2) °C after specified conditioning.

v 0

τ Luminous transmittance in the darkened state as reached at (23 ± 2) °C after specified irradi-

v 1
ation simulating mean outdoor conditions.

τ Luminous transmittance in the darkened state as reached at (5 ± 2) °C after specified irradi-

v W
ation simulating outdoor conditions at low temperatures.

τ Luminous transmittance in the darkened state as reached at (35 ± 2) °C after specified irradi-

v S
ation simulating outdoor conditions at high temperatures.

τ Luminous transmittance in the darkened state as reached at (23 ± 2) °C after specified irradi-

v R
ation simulating reduced light conditions.

NOTE 1 When describing a photochromic lens, the luminous transmittance refers to the faded state, before

exposure to optical radiation, and the darkened state, after exposure to optical radiation.

NOTE 2 The symbol for the luminous transmittance in reduced light conditions, τ , has been changed

v R

from τ which is in ISO 13666. This is to avoid possible confusion with the luminous transmittance measured

v A
in CIE standard illuminant A, which is also frequently given the symbol τ .
v A
5 Classification
Spectacle lenses are classified with respect to transmittance as follows:
a) clear lenses, with no intended colour/tint in transmission;
b) uniformly tinted lenses;
c) gradient-tinted lenses;
d) photochromic lenses;
e) polarizing lenses.
NOTE b) or c) may be combined with d) and/or e).
6 Requirements
6.1 General

The fundamental requirements for uncut finished lenses, including reference to 6.3 in this part

of ISO 8980, are in ISO 14889. For other than photochromic lenses, the requirements shall apply at a

temperature of (23 ± 5) °C, and shall apply at the design reference point unless specified otherwise. For

photochromic lenses, the applicable temperatures are given in Table 1.
6.2 General transmittance requirements
6.2.1 Tint descriptions, categories, and UV transmittance requirements

Spectacle lenses shall be attributed to one of five tint descriptions or luminous transmittance categories

as specified in Table 2. Lenses shall be tested as described in Clause 7.
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A spectacle lens categorized by the manufacturer as having a luminous transmittance τ that is in

category 0, 1, 2 or 3 shall have a luminous transmittance at its design reference point that shall not lie

outside the limits of the stated category by more than 2 % absolute.

A spectacle lens categorized by the manufacturer as having a luminous transmittance τ that is in

category 4 shall have a luminous transmittance τ at its design reference point that shall not lie outside

the limits of that category by more than 20 % relative to the stated luminous transmittance.

For gradient-tinted lenses, the overlap in luminous transmittance allowed between categories shall be

double that for uniformly tinted lenses.

A lens categorized by the manufacturer as having a luminous transmittance τ that is in a particular

category shall comply with the ultraviolet (UV) transmittance requirements of that category, regardless

of the actual luminous transmittance. For example, a lens nominated to have a luminous transmittance

in category 2 but actually having a luminous transmittance of 45 % (category 1, or category 2 allowing

for the 2 % tolerance) shall comply with the UV transmittance requirements of a category 2 lens.

Any lens that does not meet the UV transmittance requirements in Table 2 must include the warning

indicated in 8 f).
6.2.2 Tolerances on luminous transmittance of tinted lenses

It is recommended that a tint should be ordered by reference to a manufacturer's sample. Such a tint

should not be visibly different from the tint of the sample and its assessment is not restricted to its

luminous transmittance τ measured by spectrophotometer.

A lens ordered by a specific luminous transmittance τ shall have a measured τ at the design reference

v v
point within ± 8 % absolute of that ordered.
The tint of the two lenses of a pair should not be visibly different.

Table 2 — Categories for luminous transmittance and the related permissible transmittance in

the ultraviolet solar spectral range
Visible spectral range Ultraviolet spectral range
380 nm to 780 nm 315 nm to 380 nm 280 nm to 315 nm
UV-A UV-B
Range of luminous Maximum value of solar Maximum value of solar
Luminous
Tint descrip-
transmittance UV-A transmittance UV-B transmittance
transmittance
tion
category
τ τ τ
v SUVA SUVB
Clear or very
0 τ > 80 % τ 0,05 τ
v v v
light tint
Light tint 1 43 % < τ ≤ 80 % τ 0,05 τ
v v v
1,0 % absolute or 0,05 τ ,
Medium tint 2 18 % < τ ≤ 43 % 0,5 τ
v v
whichever is greater
Dark tint 3 8 % < τ ≤ 18 % 0,5 τ 1,0 % absolute
v v
1,0 % absolute or 0,25 τ ,
Very dark tint 4 3 % < τ ≤ 8 % 1,0 % absolute
whichever is greater

6.3 Spectral transmittance requirements of spectacle lenses intended for driving and

road use
6.3.1 General

Spectacle lenses having a luminous transmittance τ less than or equal to 8 % are not intended for

driving and road use. This clause therefore does not contain requirements for such lenses.

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6.3.2 Spectral transmittance

The spectral transmittance τ(λ) at any wavelength in the range 475 nm to 650 nm shall be not less

than 0,20 τ .
6.3.3 Daylight use

The luminous transmittance τ of spectacle lenses for driving and road use during daylight shall be

more than 8 % at the design reference point.
6.3.4 Driving in twilight or at night

Spectacle lenses with a luminous transmittance τ less than 75 % shall not be used for driving and road

use in twilight or at night. In the case of photochromic spectacle lenses, this requirement applies when

tested in accordance with 7.5.3.5.

6.3.5 Relative visual attenuation coefficient (quotient) for incandescent traffic signal light

detection

Spectacle lenses for driving and road use shall have a relative visual attenuation coefficient

(quotient), Q , not less than:
signal
a) 0,80 for Q ;
red
b) 0,60 for Q ;
yellow
c) 0,60 for Q ;
green
d) 0,40 for Q .
blue

The relative visual attenuation coefficients (quotients), Q , shall be calculated according

signal

to ISO 13666:2019, 3.17.8, using the spectral data in Annex A. An alternative calculation can be made in

summation form according to F.6 using the spectral data in Annex A.
6.4 Additional transmittance requirements for special types of spectacle lenses
6.4.1 Photochromic spectacle lenses
6.4.1.1 General

Photochromic spectacle lenses are usually attributed to two categories, corresponding to the faded

state and to the darkened state. Additional lens states may be specified under various temperatures

(see 6.4.1.3) and moderate light levels (see 6.4.1.4). Transmittances shall be determined according to

the method in 7.5. The UV transmittance in any state shall conform to the values specified for that

category in Table 2.
6.4.1.2 Photochromic response

When tested by the methods described in 7.5.3.1 to 7.5.3.3, the ratio of the luminous transmittance

of a photochromic lens (see 7.5.1) in its faded state τ and, after 15 min irradiation, in its darkened

v 0
state τ shall be at least 1,25, i.e.
v 1
v 0
≥12, 5
v 1
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6.4.1.3 Photochromic response at various temperatures

If the influence of temperature on photochromic response is stated, it shall be determined by measuring

the luminous transmittance of the lens (see 7.5.1) in the darkened state using the procedure described

in 7.5.3.6 at 5 °C (τ ), 23 °C (τ ) and 35 °C (τ ).
v W v 1 v S

The manufacturer can use additional temperatures, provided this information is made available.

6.4.1.4 Photochromic response at moderate light levels

If the photochromic response at moderate light levels is stated, it shall be determined by measuring the

luminous transmittance of the lens (see 7.5.1) in the darkened state τ using the procedure described

v R
in 7.5.3.4.
6.4.2 Polarizing spectacle lenses
6.4.2.1 Polarizing efficiency

When tested according to the method in 7.6, the polarizing efficiency shall be > 78 % for luminous

transmittance categories 2, 3, 4 and > 60 % for luminous transmittance category 1.

6.4.2.2 Orientation

When tested according to the method in 7.6, the actual plane of transmittance shall be at (90 ± 5)° from

the reference.
This reference is constituted by:

— the permanent alignment reference markings for power-variation lenses and position-specific

single-vision lenses;

— the dividing line for straight-top and E-line multifocal lenses, and to the tangent to the mid-point of

the dividing line of curved-top multifocal lenses in their intended orientation;

— the marking according to 6.4.2.3 for single-vision and multifocal lenses with no other geometric

orientation properties;

— for finished lenses, the horizontal line joining the boxed centres of the lenses when fitted to the

intended frame.
6.4.2.3 Marking

Polarizing finished single-vision and multifocal lenses with no other geometric orientation properties

shall include permanent or non-permanent marking on the horizontal meridian to identify clearly the

intended horizontal orientation.

Alternatively, if manufacturers or suppliers choose to include marking on the vertical meridian of the

finished lenses to indicate the plane of transmission, this alternative marking shall be clearly identified.

In this case, the same tolerance as stated in 6.4.2.2 (± 5°) applies for the difference between the marking

and the actual plane of transmittance.
6.4.3 Gradient-tinted spectacle lenses

The requirements for gradient-tinted spectacle lenses shall be determined at the design reference point

of the spectacle lens. It is recommended that gradient tints be ordered by reference to a manufacturer’s

sample lens, identification code, name or reference number.
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6.5 Resistance to ultraviolet radiation

Following irradiation as specified in 7.7, the absolute change in the luminous transmittance (τ ' – τ )

V V

of the lenses shall be less than or equal to 5 % absolute where τ ' is the luminous transmittance

after irradiation. This tolerance shall also apply to photochromic lenses in the faded state when

measured after conditioning according to 7.5.3.1, following testing according to 7.7.

In addition, the following shall be met:
v 0
a) for photochromic filters shall be ≥ 1,25;
v 1
b) the UV requirements for the initial τ shall continue to be satisfied;

c) if originally intended for driving and road use, the requirements of 6.3 shall continue to be satisfied.

7 Test methods
7.1 General

This clause specifies reference methods for transmittance properties of spectacle lenses.

For purposes of quality control, etc., alternative test methods can be used provided they have been

shown to be equivalent and include uncertainties of measurement no greater than those required of the

reference method.
7.2 Spectral transmittance

The uncertainties of the test methods determining transmittance values shall be not greater than:

— 2 % absolute, for transmittance > 20 %;
— 1 % absolute, for luminous transmittance ≤ 20 %;

— 10 % relative, for UV transmittance of lenses with luminous transmittance ≤ 20 %.

These measurement uncertainties shall be based on a confidence level of 95 %.
NOTE Guidelines for evaluating uncertainty can be found in ISO/IEC Gu
...