EN ISO 8980-3:2013

SLOVENSKI STANDARD
01-februar-2014
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SIST EN ISO 8980-3:2005
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Ophthalmic optics - Uncut finished spectacle lenses - Part 3: Transmittance
specifications and test methods (ISO 8980-3:2013)
Augenoptik - Rohkantige fertige Brillengläser - Teil 3: Transmissionsanforderungen und
Prüfverfahren (ISO 8980-3:2013)
Optique ophtalmique - Verres de lunettes finis non détourés - Partie 3: Spécifications
relatives au facteur de transmission et méthodes d'essai (ISO 8980-3:2013)
Ta slovenski standard je istoveten z: EN ISO 8980-3:2013
ICS:
11.040.70 Oftalmološka oprema Ophthalmic equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 8980-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2013
ICS 11.040.70 Supersedes EN ISO 8980-3:2004
English Version
Ophthalmic optics - Uncut finished spectacle lenses - Part 3:
Transmittance specifications and test methods (ISO 8980-
3:2013)
Optique ophtalmique - Verres de lunettes finis non détourés Augenoptik - Rohkantige fertige Brillengläser - Teil 3:
- Partie 3: Spécifications relatives au facteur de Transmissionsanforderungen und Prüfverfahren (ISO 8980-
transmission et méthodes d'essai (ISO 8980-3:2013) 3:2013)
This European Standard was approved by CEN on 7 September 2013.

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, 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
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8980-3:2013: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
This document (EN ISO 8980-3:2013) 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 April 2014, and conflicting national standards shall be withdrawn at the
latest by October 2016.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 8980-3:2004.
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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 8980-3:2013 has been approved by CEN as EN ISO 8980-3:2013 without any modification.

INTERNATIONAL ISO
STANDARD 8980-3
Third edition
2013-10-01
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
Reference number
ISO 8980-3:2013(E)
©
ISO 2013
ISO 8980-3:2013(E)
© ISO 2013
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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved

ISO 8980-3:2013(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 4
5 Classification . 4
6 Requirements . 4
6.1 General . 4
6.2 General transmittance requirements . 5
6.3 Spectral transmittance requirements of spectacle lenses intended for road use
and driving . 6
6.4 Additional transmittance requirements for special types of spectacle lenses . 6
6.5 Resistance to radiation . 7
7 Test methods . 8
7.1 General . 8
7.2 Spectral transmittance . 8
7.3 Luminous transmittance and relative visual attenuation coefficient (quotient) . . 8
7.4 Ultraviolet transmittance . 8
7.5 Transmittance properties of photochromic spectacle lenses and
photochromic specimens . 9
7.6 Test methods for polarizing spectacle lenses .11
7.7 Determination of resistance to radiation .13
8 Identification .14
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
Annex D (informative) Spectral data for calculating relative visual attenuation quotients for LED
signal lights .25
Annex E (informative) Spectral radiation risks .28
Annex F (informative) Example of the calculation of luminous transmittance,τ .29
V
Bibliography .31
ISO 8980-3:2013(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. 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. 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.
The committee responsible for this document is ISO/TC 172, Optics and photonics, Subcommittee SC 7,
Ophthalmic optics and instruments.
This third edition cancels and replaces the second edition (ISO 8980-3:2003), which has been technically
revised. In particular, the requirement in 6.3.2 for lenses intended for road use and driving has been
amended with an extension of three years for the continued manufacture of existing products.
ISO 8980 consists of the following parts, under the general title Ophthalmic optics — Uncut finished
spectacle lenses:
— Part 1: Specifications for single-vision and multifocal lenses
— Part 2: Specifications for progressive power lenses
— Part 3: Transmittance specifications and test methods
— Part 4: Specifications and test methods for anti-reflective coatings
— Part 5: Minimum requirements for spectacle lens surfaces claimed to be abrasion-resistant
iv © ISO 2013 – All rights reserved

INTERNATIONAL STANDARD ISO 8980-3:2013(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 finished spectacle
lenses and mounted pairs, including attenuation of solar radiation.
This part of ISO 8980 is not applicable to
— spectacle lenses having particular transmittance or absorption characteristics prescribed for
medical reasons;
— products where specific personal protective equipment transmittance standards apply;
— products intended for direct observation of the sun, such as for solar-eclipse viewing.
NOTE Optical and geometric requirements for uncut finished spectacle lenses are specified in ISO 8980-1
and ISO 8980-2, and for mounted lenses, in ISO 21987.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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, Colorimetry — Part 1: CIE standard colorimetric observers
ISO 11664-2, Colorimetry — Part 2: CIE standard illuminants
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 apply.
NOTE 1 For the convenience of the reader, the following definitions have been reproduced from ISO 13666.
NOTE 2 Absorptance, reflectance and transmittance are usually expressed as percentages. The equations in
this clause are written in this form. Although the definitions use integrals, in practice summation, typically at
1 nm, 5 nm or 10 nm intervals, is performed to calculate the various transmittances.
3.1
mean UV-A transmittance
τ
UVA
mean transmittance between 315 nm and 380 nm
380 nm
ττ=×100 ()λλ⋅d %
UVA
∫
65 nm
315 nm
ISO 8980-3:2013(E)
[ISO 13666:2012, definition 15.3.1]
3.2
solar UV-A transmittance
τ
SUVA
mean of the spectral transmittance between 315 nm and 380 nm weighted by the solar radiation
distribution E (λ) at sea level, for air mass 2, and the relative spectral effectiveness function for
s
UV radiation S(λ)
380 nm
τλ()⋅⋅ES()λλ()⋅dλ
s
∫
315 nm
τ =×100 %
SUVA
3880 nm
ES()λλ⋅⋅() dλ
s
∫
315 nm
Note 1 to entry: The complete weighting function W(λ) is the product of E (λ) and S(λ) and is given in Table B.1.
s
[SOURCE: ISO 13666:2012, definition 15.3.2]
3.3
solar UV-B transmittance
τ
SUVB
mean of the spectral transmittance between 280 nm and 315 nm weighted by the solar radiation
distribution E (λ) at sea level, for air mass 2, and the relative spectral effectiveness function for UV
S
radiation S(λ)
315 nm
τλ()⋅⋅ES()λλ()⋅dλ
s
∫
280 nm
τ =×100 %
SUVB
315 nm
ES()λλ⋅⋅() dλ
s
∫
280 nnm
Note 1 to entry: The complete weighting function W(λ) is the product of E (λ) and S(λ) and is given in Table B.1.
s
[SOURCE: ISO 13666:2012, definition 15.3.3]
3.4
luminous transmittance
τ
V
ratio of the luminous flux transmitted by the lens or filter to the incident luminous flux
780 nm
τλ()⋅VS()λλ⋅ ()⋅dλ
D65
∫
380 nm
τ =×100 %
V
780 nm
VSλλ⋅ ⋅ dλ
() ()
D65
∫
380 nm
where
τ(λ) is the spectral transmittance of the spectacle lens;
V(λ) is the spectral luminous efficiency function for daylight (see ISO 11664-1);
S (λ) is the spectral distribution of radiation of CIE standard illuminant D65 (see ISO 11664-2).
D65
Note 1 to entry: The spectral values of the product of the spectral radiation distributions S (λ) of the CIE
D65
standard illuminant D65 and the eye’s spectral luminous efficiency function V(λ) are given in Table A.2.
2 © ISO 2013 – All rights reserved

ISO 8980-3:2013(E)
[SOURCE: ISO 13666:2012, definition 15.4]
3.5
relative visual attenuation coefficient (quotient) for incandescent traffic signal light
recognition/detection
Q-value
ratio of the luminous transmittance of a tinted lens for the spectral radiant power distribution of the
light emitted by a traffic signal τ to the luminous transmittance of the same lens for CIE standard
signal
illuminant D65 (τ )
V
τsignal
Q =
τ
V
where
τ is the luminous transmittance of the lens for the spectral radiant power distribution of the
signal
traffic signal light.
Note 1 to entry: Q-values can be determined for each of blue, green, amber (yellow) and red signal lights. τ is
signal
given by the equation:
780 nm
τλ()⋅⋅τλ() VS()λλ⋅⋅() dλ
A
S
∫
380 nm
τ signal=×100 %
780 nm
τλ()⋅V (λ))(⋅⋅S λλ) d
S A
∫
380 nm
where
τ (λ) is the spectral transmittance of the traffic signal lens;
S
S (λ) is the spectral distribution of radiation of CIE standard illuminant A (or 3 200 K light
A
source for blue signal light) (see ISO 11664-2);
Note 2 to entry: The spectral values of the products of the spectral distributions S (λ) of the illuminant A, the
A
spectral luminous efficiency function V(λ) of the eye and the spectral transmittance τ (λ) of the traffic signal lens
S
are given in Table A.1, where E (λ)=S (λ)×τ (λ).
Signal A S
Note 3 to entry: Calculations are currently based on the measured values of E(λ) for traffic signal lights using
incandescent quartz-halogen lamps. They previously used the product τ (λ) ·S (λ) of the spectral transmittance
S A
of the traffic signal filter and the spectral distribution of radiation of CIE standard illuminant A. Calculations
using the values for quartz-halogen lamps and LED signals will give different results
Note 4 to entry: Adapted from ISO 13666:2012, definition 15.5.
3.6
polarizing efficiency
property of a polarizing lens, describing the percentage of the transmitted light that is polarised, defined
by the equation
ττ−
p,maxp,min
P=×100 %
ττ+
p,maxp,min
where
ISO 8980-3:2013(E)
τ is the maximum value of luminous transmittance as determined with 100% linearly polar-
p,max
ised radiation;
τ is the minimum value of luminous transmittance as determined with 100% linearly polar-
p,min
ised radiation.
Note 1 to entry: Adapted from ISO 13666:2012, definition 8.1.12.3.
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 condi-
V0
tioning.
τ Luminous transmittance in the darkened state as reached at (23 ± 2) °C after specified
V1
irradiation simulating mean outdoor conditions.
τ Luminous transmittance in the darkened state as reached at (5± 2) °C after specified irra-
VW
diation simulating outdoor conditions at low temperatures.
τ Luminous transmittance in the darkened state as reached at (35± 2) °C after specified
VS
irradiation simulating outdoor conditions at high temperatures.
τ Luminous transmittance in the darkened state as reached at (23 ± 2) °C after specified
VA
irradiation simulating reduced light conditions.
5 Classification
Spectacle lenses are classified with respect to transmittance as follows:
a) clear spectacle lenses, having no intended colour (including grey) in transmission;
b) uniformly tinted spectacle lenses;
c) gradient-tinted spectacle lenses;
d) photochromic spectacle lenses;
e) polarizing spectacle lenses.
NOTE Two or more of the above classifications may be combined.
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. The requirements shall apply at a temperature of (23 ± 5) °C, and shall apply
at the design reference point, unless specified otherwise.
4 © ISO 2013 – All rights reserved

ISO 8980-3:2013(E)
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, and shall be tested as described in Clause 7.
A spectacle lens intended to have a luminous transmittance τ that is in categories 0, 1, 2 and 3 shall have
V
a luminous transmittance at its design reference point that shall not lie outside the limits of the stated
category by more than 2 % absolute. For example, a lens intended to have a luminous transmittance
of 40 % but actually having a transmittance of 45 % shall comply with the UV requirements of a
category 2 lens.
A spectacle lens intended to have a luminous transmittance τ that is in category 4 shall have a luminous
V
transmittance τ at its design reference point that shall not lie outside the limits of that category by
V
more than 20 % relative to the stated luminous transmittance.
All lenses shall meet the specified UV requirements corresponding to their intended luminous
transmittance τ in Table 2, but those clear glass spectacle lenses of category 0 for which no specific
V
claim is made as to UV transmittance performance are excluded from the UV requirements of Table 2.
NOTE This exclusion applies because some clear crown glass lenses cannot meet the UV-B requirement.
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
shall not be obviously dissimilar from the tint of the sample and its assessment is not restricted by its
luminous transmittance τ measured by spectrophotometer.
V
For a lens ordered by a specific luminous transmittance τ shall have a measured τ at the design
V V
reference point within ± 8 % absolute of that ordered. The tint of the two lenses of a pair should not be
obviously dissimilar.
Table 2 — Categories for luminous transmittance and the related permissible transmittance in
the ultraviolet solar spectral range
Visible spectral range Ultraviolet spectral range
Range of luminous Maximum value of solar Maximum value of solar
transmittance UV-A transmittance UV-B transmittance
τ τ τ
V SUVA SUVB
Luminous
to > 315 nm to 380 nm > 280 nm to 315 nm
Tint transmit- from over
description tance %
% UV-A UV-B
category
Clear or
very light 0 80,0 100 τ 0,05 τ
V V
tint
Light tint 1 43,0 80,0 τ 0,05 τ
V V
1,0 % absolute or 0,05 τ ,
V
Medium tint 2 18,0 43,0 0,5 τ
V
whichever is greater
Dark tint 3 8,0 18,0 0,5 τ 1,0 % absolute
V
Very dark 1,0 % absolute or 0,25 τ ,
V
4 3,0 8,0 1,0 % absolute
tint whichever is greater
ISO 8980-3:2013(E)
6.3 Spectral transmittance requirements of spectacle lenses intended for road use and
driving
6.3.1 General
Spectacle lenses having a luminous transmittance τ less than or equal to 8 % are not intended for road
V
use and driving. This clause therefore does not contain requirements for such lenses.
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
0,2 τ .
V
For a period of three years from the date of publication of this part of ISO 8980, products that are
existing at the date of publication of this part of ISO 8980 that satisfy the requirement that the spectral
transmittance, τ(λ) at any wavelength in the range 500 nm to 650 nm shall be not less than 0,2 τ will
V
be deemed to pass the requirement of this part of ISO 8980.
6.3.3 Daylight use
When using illuminant D65, the luminous transmittance τ of spectacle lenses for road use and driving
V
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 road use and
V
driving 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 recognition/detection of incandes-
cent signal lights
Spectacle lenses shall have a relative visual attenuation coefficient (quotient) Q not less than:
a) 0,8 for Q ;
red
b) 0,6 for Q ;
yellow
c) 0,6 for Q ;
green
d) 0,4 for Q .
blue
The relative visual attenuation coefficient (quotient) Q shall be calculated according to 3.5, in accordance
with Table A.1.
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. The faded and darkened state transmittances shall be determined according
to the method in 7.5. The UV transmittance in both the faded and darkened states shall conform to the
values specified for both categories in Table 2.
NOTE It is not required to claim the category of the lens in its darkened state.
6 © ISO 2013 – All rights reserved

ISO 8980-3:2013(E)
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 specimen (see 7.5.1) in its faded state τ and, after 15 min irradiation, in its darkened
V0
state τ shall be at least 1,25, i.e.
V1
τ
V0
≥12, 5
τ
V1
6.4.1.3 Photochromic response at various temperatures
If photochromic temperature influence is stated, it shall be determined by measuring the luminous
transmittance of the specimen (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 ).
VW V1 VS
NOTE The manufacturer may 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 specimen (see 7.5.1) in the darkened state τ using the procedure described
VA
in 7.5.3.4 after exposure to the illumination specified in 7.5.2.1 attenuated to an intensity of 30 %.
6.4.2 Polarizing spectacle lenses
6.4.2.1 Individual uncut polarizing lenses
When tested according to the method in 7.6, the polarizing efficiency as calculated in 3.6 shall be > 78 %
for luminous transmittance categories 2, 3, 4 and > 60 % for luminous transmittance category 1.
If there is a marking on the spectacle lens indicating the intended direction of horizontal orientation,
then the actual plane of transmittance shall be at (90 ± 3)° from this marking.
6.4.2.2 Mounted pairs of polarizing lenses
If the lenses mounted in spectacles are claimed to be polarizing for sun glare attenuation, the lenses
shall be fitted in the frame so that their planes of transmission do not deviate from the vertical by more
than ± 5º when tested according to the method in 7.6.
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.
6.5 Resistance to 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
V
irradiation. In addition, the following shall be met:
τ
V0
a) for photochromic filters shall be ≥ 1,25;
τ
V1
b) the UV requirements for the initial τ shall continue to be satisfied;
V
c) if originally intended for road use and driving, the requirements of 6.3 shall continue to be satisfied;
ISO 8980-3:2013(E)
d) where a UV transmittance lower (i.e. better) than that specified in Table 2 is claimed, then this
transmittance 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 may be used if shown to be equivalent.
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 %.
7.3 Luminous transmittance and relative visual attenuation coefficient (quotient)
7.3.1 The spectral distribution of standard illuminant D65 as specified in ISO 11664-2 and the luminous
efficiency of the average human eye for daylight vision (2° observer) as specified in ISO 11664-1 shall be
used to determine the luminous transmittance, τ . When calculating the luminous transmittance, τ ,
V V
from the spectral transmittance τ(λ), the step width shall not exceed 10 nm.
7.3.2 Relative visual attenuation coefficient for signal light recognition/detection [incandescent]. When
calculating the relative visual attenuation coefficient (quotient), Q, for signal lights from the spectral
transmittance τ(λ), the step width shall not exceed 10 nm. The relevant formula, from ISO 13666, is:
τ
signal
Q=
τ
V
where
τ is given in 3.4;
V
τ is given in 3.5;
signal
E (λ)×V(λ) for red, yellow, green and blue incandescent lamps are listed in Table A.1.
Signal
NOTE For information, E (λ)×V(λ) for red, yellow, green and blue light emitting diode (LED) signals lights
Signal
are listed in informative Annex D.
7.4 Ultraviolet transmittance
7.4.1 Principle
The ultraviolet transmittance in the spectral range from 280 nm to 380 nm of the uncut finished
spectacle lens shall be determined using a spectrophotometer.
8 © ISO 2013 – All rights reserved

ISO 8980-3:2013(E)
7.4.2 Apparatus
The spectrophotometer shall:
a) operate over the wavelength range from 280 nm to 380 nm;
b) have a spectral bandwidth (full width at half maximum, FWHM) not exceeding 5 nm;
c) be capable of measuring spectral data at wavelength intervals of 5 nm or less.
7.4.3 Calculation
When calculating bioactinically weighted solar ultraviolet transmittance values τ from 280 nm to
SUVB
315 nm and τ from 315 nm to 380 nm, for data recorded with fixed (i.e. constant) spectral bandwidths
SUVA
from 2 nm to 5 nm, the step width shall be equal to or less than the bandwidth; for data recorded with
varying spectral bandwidth, or for bandwidths smaller than 2 nm, a step width not greater than 2 nm
shall be used.
NOTE The spectral functions for the calculation of the bioactinically-weighted solar ultraviolet transmittance
values τ and τ defined in ISO 13666 are given in Annex B. Linear interpolation of these values for steps
SUVA SUVB
smaller than 5 nm is permitted.
The relevant formulae are given in ISO 13666 and Clause 3.
7.5 Transmittance properties of photochromic spectacle lenses and photochromic
specimens
7.5.1 Test specimens
The test specimens shall be plano spectacle lenses, normally with a reference thickness of (2,0 ± 0,1) mm.
If a thickness outside this range is used, the thickness shall be stated. After having undergone careful
cleaning, each specimen shall be conditioned as described in 7.5.3.1.
NOTE The base curve is not specified but should be recorded.
7.5.2 Apparatus
7.5.2.1 Irradiation source, used to darken photochromic spectacle lens.
The irradiation source (solar simulator) shall approximate as closely as practical the spectral
[4] [12]
power distribution of solar radiation defined as air mass (AM) m = 2 (see or ) at an illuminance
of 50 000 lx ± 5 000 lx, or when the luminous transmittance for night driving shall be measured, at the
illuminance specified in 7.5.3.4.
Testing shall be done with an irradiation source (e.g. a xenon high pressure lamp with filters) that
has the specified luminance of 50 000 lx ± 5 000 lx and the irradiance values given in Table 3, at the
specimen’s position. The intensity of the irradiation source shall be monitored to correct for drifts in
the output of the source.
Where testing at 15 000 lx ± 1 500 lx is specified, the irradiance related values in Table 3 shall be
multiplied by 0,30.
See Annex E for details of risks associated with solar radiation.
NOTE 1 Care should be taken to ensure that irradiation from the source does not interfere with the
transmittance measurements.
NOTE 2 To attenuate the intensity of the irradiation source (solar simulator) for the measurement of the
photochromic response of a photochromic spectacle lens at moderate light levels (see 6.4.1.4), a neutral density
filter may be used, suitably positioned in the irradiation beam.
ISO 8980-3:2013(E)
Table 3 — Irradiance for testing photochromic spectacle lenses
Wavelength range Irradiance Irradiance tolerance
2 2
nm W/m W/m
300 to 340 < 2,5 —
340 to 380 5,6 ± 1,5
380 to 420 12 ± 3,0
420 to 460 20 ± 3,0
460 to 500 26 ± 2,6
7.5.2.2 Specimen chamber, to maintain the specimen at the required temperature, 5 °C, 23 °C or 35 °C,
to within ± 2 °C during exposure to the solar simulator.
NOTE 1 A water bath may be used to achieve temperature control. Since immersion of the specimen(s) in
water reduces the reflectivity of the surfaces, the transmittance values determined using water immersion may
require correction to yield the equivalent “air” values. Calibration of the equipment may be checked using a non-
photochromic test sample with refractive index within ± 0,01 of the refractive index of the specimen.
NOTE 2 If a water bath is used, in order to avoid modifying the photochromic performance due to water
absorption into the lens, care should be taken not to immerse specimens longer than necessary.
7.5.2.3 Spectrophotometer, capable of recording spectral transmittance data from 280 nm to 780 nm
within a time span that does not affect the results. Alternatively, the 280 nm to 380 nm range may be
measured immediately after removal from the irradiation source to ensure the performance measurement
is not affected by the measuring beam.
For determining transmittance properties in the darkened state, the spectrophotometer shall:
a) have a spectral bandwidth not greater than 5 nm;
b) be capable of measuring spectral data at wavelength intervals of 5 nm or less.
7.5.3 Determination of transmittance
7.5.3.1 Conditioning
Use the procedure specified by the manufacturer in their product technical information to attain the
faded state of the lens. If no procedure is specified by the manufacturer, store the specimen(s) in the
dark at (65 ± 5) °C for (2,0 ± 0,2) h. Then store the specimen in the dark at (23 ± 5) °C for a minimum
of 12 h before testing.
7.5.3.2 Luminous and UV transmittance in the faded state
After conditioning and before exposing the specimen to any irradiation source, determine the luminous
transmittance τ and the UV transmittance of the specimen in its faded state, using the apparatus
V0
described in 7.5.2 with the specimen at a temperature of (23 ± 2) °C.
7.5.3.3 Luminous and UV transmittance in the darkened state
While maintaining the specimen temperature at (23 ± 2) °C illuminate the specimen with the irradiation
source for (15 ± 0,1) min and determine the luminous transmittance τ and the UV transmittance of the
V1
specimen in the darkened state using the apparatus described in 7.5.2.
10 © ISO 2013 – All rights reserved

ISO 8980-3:2013(E)
7.5.3.4 Luminous transmittance at moderate light levels
When determining the photochromic response at moderate light levels, repeat the procedure described
in 7.5.3.1 to 7.5.3.3 at (23 ± 2) °C at an illuminance of 15 000 lx ± 1 500 lx and maintain the same relative
spectral power distribution with the solar simulator specified in 7.5.2.1.
7.5.3.5 Luminous and UV transmittance for driving in twilight or at night
After conditioning as described in 7.5.3.1 and while maintaining the specimen temperature at (23 ± 2) °C,
illuminate the specimen under the conditions described in 7.5.3.4 for (15 ± 0,1) min. Afterwards,
store the specimen at (23 ± 2) °C for (60 ± 1) min either in the dark or under reduced illumination,
depending on the manufacturer’s instructions. Then determine the luminous transmittance τ and the
V
UV transmittance of the specimen using the apparatus described in 7.5.2.
7.5.3.6 Luminous and UV transmittance at various temperatures
If the luminous transmittance or photochromic response at a temperature different from 23°C is stated,
it shall be determined by the procedure described in 7.5.3.1 to 7.5.3.3 at (5 ± 2) °C and (35 ± 2) °C.
7.6 Test methods for polarizing spectacle lenses
7.6.1 Mean luminous transmittance
The transmittance value of polarizing lenses shall be determined using unpolarized light or shall be
calculated as a mean value of the transmittance values determined for two mutually perpendicular
orientations of the plane of transmission of the lens.
7.6.2 Polarizing efficiency
7.6.2.1 Principle
The polarizing efficiency of a polarizing lens is determined with radiation polarized parallel and
perpendicular to the plane of transmission. Before measuring the sample the incident beam should be
essentially 100 % linearly polarized by the introduction of a suitable polarizing medium and calibrating
to 100 %. The spectacle lens or the linear polarizer is rotated to the point of maximum transmittance. At
this orientation, the luminous transmittance, τ , is recorded. The spectacle lens or linear polarizer
p,max
is then rotated 90° and the luminous transmittance, τ , is recorded. The polarizing efficiency shall
p,min
then be calculated according to 3.6.
7.6.2.2 Spectrophotometer method
For the measurements, a spectrophotometer shall be used in combination with a polarizing medium
of known plane of polarization in the light path. The spectral transmittance shall be determined in
accordance with 7.2 and 7.3.
7.6.2.3 Broadband method
Select a combination of source of light and filter to give a correlated colour temperature of (6 500 ± 1 000) K
(approximating CIE Standard Illuminant D65 in the visible region). Select a detector with approximately
the spectral sensitivity of the CIE 2° Standard Observer (ISO 11664-1) and a visible spectral range that is
linear to within ± 0,5 %. Collimate the beam of light from the source and insert the linear polarizer and
the spectacle lens under test between the collimator and detector.
ISO 8980-3:2013(E)
7.6.3 Plane of transmission
7.6.3.1 General
For the determination of the plane of transmission, a polarizer of known plane of polarization in the
light path shall be used, e.g., by the method given in 7.6.3.2 and 7.6.3.3.
7.6.3.2 Apparatus
See Figure 1.
A pair of polarizers are cut to give planes of transmission at a +3° and a – 3° angle about the horizontal.
The top and bottom halves of the polarizers shall be then joined together and glass mounted, with the
line of the join horizontal to form a split field polarizer. The split-field polarizer shall be capable of being
rotated by means of a lever carrying a corresponding pointer. The pointer transverses a scale calibrated
in degrees left or right of zero. The split fields shall be illuminated from behind by a diffused light source.
Make sure that the top and bottom register bars are long enough to fix a complete spectacle frame
parallel to the horizontal axis for measurements of mounted lenses.
7.6.3.3 Procedure for an uncut lens
Mount the lens on the apparatus between the two register bars with the indicating marks aligned along
180° and with its front surface towards the split-field polarizer. Ensure that the split-field appears in the
centre of the lens by means of vertical adjusters.
Move the lever from side to side until the top and bottom halves of the illuminated split-field appear of
equal luminance when viewed through the lens.
Read off the pointer position to give the deviation in degrees (plus or minus) of the plane of transmission
of the lens from the vertical.
7.6.3.4 Procedure for mounted lenses
Mount the spectacles on the apparatus between the two register bars with the front surface of the
lenses towards the split fields. Ensure that the split field appears in the centre of the lens by means of
vertical adjusters.
For the left lens, move the lever from side to side until the top and bottom halves of the illuminated split
field appear of equal luminance when viewed through the lens.
Read off the pointer position to give the deviation in degrees (plus or minus) of the plane of transmission
of the lens from the vertical.
Repeat the procedures for the right lens.
12 © ISO 2013 – All rights reserved

ISO 8980-3:2013(E)
Key
1 scales
2 top register bar
3 split field polarizer
4 bottom register bar
5 polarizing spectacle lens
6 split field rotation lever
7 plane of transmission
8 intended horizontal orientation of lens
Figure 1 — Principle of an apparatus for the determination of the plane of transmission of the
lens from the vertical
7.7 Determination of re
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