ISO 5868:2025
(Main)Ophthalmic optics and instruments — Anomaloscopes for the diagnosis of red-green colour vision deficiencies
Ophthalmic optics and instruments — Anomaloscopes for the diagnosis of red-green colour vision deficiencies
This document applies to anomaloscopes used to examine red-green-colour vision by investigating the colour match of a mixture of red and green compared with yellow, known as the “Rayleigh equation”. This document specifies the requirements for optical and technical parameters, which are of physiological relevance to ensure that the measured values on the eye of the examinee are independent of the technical characteristics of the anomaloscope used.
Optique et instruments ophtalmiques — Anomaloscopes pour le diagnostic des déficiences de la vision des couleurs rouge-vert
General Information
Standards Content (Sample)
International
Standard
ISO 5868
First edition
Ophthalmic optics and
2025-05
instruments — Anomaloscopes for
the diagnosis of red-green colour
vision deficiencies
Optique et instruments ophtalmiques — Anomaloscopes pour le
diagnostic des déficiences de la vision des couleurs rouge-vert
Reference number
© ISO 2025
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General . 2
5 Spectral characteristics of the lights . 2
6 Stimulus angular subtense and luminance . 4
7 Graduation, mean standard match . . 4
8 Neutral adaptation . . 4
9 Test methods for standard conformity . 5
9.1 General .5
9.2 Determination of conformity.5
10 Marking . . 5
11 Accompanying documents . . 5
Annex A (informative) Explanation of the derivation of equivalent wavelength . 6
Annex B (normative) Application of uncertainty of measurement . 9
Bibliography .11
iii
Foreword
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iv
Introduction
Laws and guidelines give characteristics of colour vision for qualification in certain occupational activities
which, among other things, specify findings in the form of anomalous quotients that are determined using
anomaloscopes.
For the quality assurance of the examination there is an interest to standardize the properties of
anomaloscopes internationally. This document undertakes this, based, in part, on the provisions of the
national standard DIN 6160.
v
International Standard ISO 5868:2025(en)
Ophthalmic optics and instruments — Anomaloscopes for the
diagnosis of red-green colour vision deficiencies
1 Scope
This document applies to anomaloscopes used to examine red-green-colour vision by investigating the
colour match of a mixture of red and green compared with yellow, known as the “Rayleigh equation”. This
document specifies the requirements for optical and technical parameters, which are of physiological
relevance to ensure that the measured values on the eye of the examinee are independent of the technical
characteristics of the anomaloscope used.
2 Normative references
The following documents are referred to in the text in such a way that some or all 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 15004-1, Ophthalmic instruments — Fundamental requirements and test methods — Part 1: General
requirements applicable to all ophthalmic instruments
ISO/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
IEC 60601-1, Medical electrical equipment — Part 1: General requirements for basic safety and essential
performance
ISO/CIE 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
anomaloscope
apparatus for quantitative examination of
human colour vision enabling an accurate reproducible optical mixture of narrow band red and green lights
to be produced and this mixture to be compared with a narrow band yellow light
3.2
anomalous quotient
anomalquotient
anomaloquotient
Q
A
anomalous quotient calculated according to the following formula:
()RP−
P
Q = (1)
A
RM−
()
M
where
P is the red-green scale setting of the match of the examinee;
M is the average red-green scale setting of the matches of colour-normal examinees;
R is the full scale reading of the mixture scale at pure red, zero being the scale reading at pure green.
3.3
equivalent wavelength
wavelength of light that, in some specified respect, has the same property as the heterogeneous beam under
consideration
Note 1 to entry: In this application the “specified respect” is taken as the minimum chromaticity difference between
the light and the spectral wavelength in CIE 1976, u’v’ (ISO/CIE 11664-calculated using the CIE 2° Standard Observer
(ISO/CIE 11664-1).
Note 2 to entry: Any linear transformation of CIE 1931 diagram will give the same result.
[SOURCE: https:// www .electropedia .org/ 881 -04 -38, modified — definition slightly rephrased.]
3.4
spectral half power bandwidth
spectral bandwidth
maximum difference between the wavelengths for which the spectral power (energy) is half of its peak value
3.5
troland
td
non-SI unit for conventional retinal illuminance and natural pupil luminance
Note 1 to entry: When the eye is viewing a surface of uniform luminance, the numerical value of the conventional
retinal illuminance or the natural pupil luminance, expressed in troland, is equal to the product of the area in square
millimetres of the limiting pupil, natural or artificial, by the luminance of the surface in candela per square metre.
[SOURCE: IEC 60050-845:1987, 845-02-16]
4 General
Anomaloscopes shall be constructed to provide a continuous change or change in steps of not more than 1 %
of the full scale value in the red - green mixture and the yellow brightness
The result can be displayed as a value from a linear scale or a ratio value of the red-green mixture in the
form of an anomalous quotient.
5 Spectral characteristics of the lights
When tested in accordance with Clause 9, the chromaticities of the lights shall lie within the areas defined in
Table 1 and Figure 1. The equivalent wavelengths limits listed in Table 2 are equivalent to the requirements in
Table 1 and Figure 1. The spectral half power bandwidths of the colours shall comply with the requirements
in Table 2.
For an explanation of the derivation of equivalent wavelength, please see Annex A.
Table 1 — Requirements on the chromaticity limits for Rayleigh equation anomaloscopes
CIE x,y corners of boundaries CIE u',v' corners of boundaries
Red x 0,726 0 0,724 2 0,733 3 0,734 7 u' 0,600 5 0,600 3 0,622 9 0,623 4
y 0,274 0 0,272 8 0,264 7 0,265 3 v' 0,509 9 0,508 8 0,505 8 0,506 5
Green x 0,251 4 0,248 4 0,310 7 0,315 9 u' 0,088 7 0,088 5 0,119 8 0,120 2
y 0,736 6 0,727 0 0,666 4 0,679 1 v' 0,584 8 0,582 8 0,578 1 0,581 1
Yellow x 0,544 8 0,537 6 0,585 1 0,593 0 u' 0,295 9 0,295 4 0,352 9 0,353 5
y 0,455 0 0,446 3 0,400 2 0,407 2 v' 0,555 4 0,551 7 0,543 1 0,546 8
Key
X u’ coordinate
Y v’ coordinate
1 red
2 green
3 yellow
NOTE The wavelengths (nm) are marked on the spectral locus.
Figure 1 — Chromaticity limits for the anomaloscope colours plotted in the CIE 1976 uniform
chromaticity diagram
Table 2 — Requirements of Table 1 expressed as equivalent wavelength and requirements for
spectral half power bandwidth limits
Equivalent wave- Spectral half power
length bandwidth
Color
nm nm
Red ≥650 ≤35
Green 543 to 552 ≤25
Yellow 585 to 593 ≤25
NOTE For colours that lie on the spectral locus, equiva-
lent wavelength is the same as dominant wavelength, no
specification of achromatic reference is necessary.
6 Stimulus angular subtense and luminance
Anomaloscopes shall present a circular or square, half-divided, uniformly illuminated field of vision of
(2,0 ± 0,2) degrees or alternatively a square with the same area. For calibration of the test field diameter,
the focus setting of the eyepiece should be 0 D. By visual inspection, the surround of the matching field shall
contain no visible light.
The two halves of the visual field shall appear to touch each other directly.
The stimulus field brightness shall have a luminance of (4,5 ± 2,3) cd/m or a retinal illuminance of
(175 ± 90) td.
NOTE Luminance is the applicable meas
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