EN ISO 10940:1998
(Main)Ophthalmic instruments - Fundus cameras (ISO 10940:1998)
Ophthalmic instruments - Fundus cameras (ISO 10940:1998)
Specification of minimum requirements in order to guarantee a sufficient quality of use.
Ophthalmische Instrumente - Funduskameras (ISO 10940:1998)
Diese Internationale Norm legt zusammen mit ISO 15004 Anforderungen und Prüfverfahren für Funduskameras fest, die ausschließlich zur Photograhie des Hintergrundes des menschlichen Auges dienen. Grundlage dieser Internationalen Norm sind Verfahren, die auf der direkten Einwirkung eines optischen Bildes auf eine photographische Emulsion beruhen. Diese Internationale Norm gilt nicht für folgende Typen von Funduskameras: - Instrumente, die für die simultane stereoskopische Photographie konstruiert sind;
Instruments ophtalmiques - Appareils photographiques du fond de l'oeil (ISO 10940:1998)
Oftalmični instrumenti - Kamere za slikanje očesnega ozadja (ISO 10940:1998)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 10940:2000
01-januar-2000
2IWDOPLþQLLQVWUXPHQWL.DPHUH]DVOLNDQMHRþHVQHJDR]DGMD ,62
Ophthalmic instruments - Fundus cameras (ISO 10940:1998)
Ophthalmische Instrumente - Funduskameras (ISO 10940:1998)
Instruments ophtalmiques - Appareils photographiques du fond de l'oeil (ISO
10940:1998)
Ta slovenski standard je istoveten z: EN ISO 10940:1998
ICS:
11.040.70 Oftalmološka oprema Ophthalmic equipment
SIST EN ISO 10940:2000 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 10940:2000
INTERNATIONAL ISO
STANDARD 10940
First edition
1998-05-01
Ophthalmic instruments — Fundus
cameras
Instruments ophtalmiques — Appareils photographiques du fond de l'œil
A
Reference number
ISO 10940:1998(E)
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SIST EN ISO 10940:2000
ISO 10940:1998(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.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75% of the member bodies casting
a vote.
International Standard ISO 10940 was prepared by Techncial Committee
ISO/TC 172, Optics and optical instruments, Subcommittee SC 7,
Ophthalmic optics and instruments.
Annex A forms an integral part of this International Standard. Annexes B
and C are for information only.
© ISO 1998
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet central@iso.ch
X.400 c=ch; a=400net; p=iso; o=isocs; s=central
Printed in Switzerland
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SIST EN ISO 10940:2000
©
INTERNATIONAL STANDARD ISO ISO 10940:1998(E)
Ophthalmic instruments — Fundus cameras
1 Scope
This International Standard, together with ISO 15004, specifies requirements and test methods for fundus cameras
operating exclusively for photography of the fundus of the human eye. This International Standard is based upon
techniques involving the direct effects of an optical image on a photographic emulsion.
This International Standard is not applicable to the following types of fundus camera:
- those designed to produce simultaneous stereoscopic photography;
- those using infrared radiation as a source of illumination for the observing system.
This International Standard takes precedence over ISO 15004, if differences exist.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
ISO 15004:1997 Ophthalmic instruments - Fundamental requirements and test methods
IEC 60601-1:1988 Medical electrical equipment - Part 1: General requirements for safety
3 Definitions
For the purposes of this International Standard, the following definitions apply.
3.1
resolving power of the fundus camera
minimum separation allowing recognition of two adjacent lines on the fundus, expressed as line pairs per millimetre
(lp/mm)
3.2
field of view
photographic angular field of view
angle subtended at the exit pupil of the eye by the maximum dimension 2r
See figure 1.
1
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ISO 10940:1998(E)
Key
1 Angular field of view
2 Entrance pupil of instrument/exit pupil of eye
Figure 1 — Meaning of dimension r for various formats
3.3
magnification of photography
ratio of the size of the image on the photosensitive target to that of the fundus at the centre of the photographic field,
assuming that the eye is emmetropic and that it has a focal length of 17 mm in air
3.4
high eye point eyepiece
eyepiece in which the exit pupil is of sufficient clearance from the eyepiece to allow spectacles to be worn
4 Requirements
4.1 General
The fundus camera shall conform to the requirements specified in ISO 15004.
4.2 Optical requirements
The fundus camera shall conform to the requirements given in table 1. These requirements are verified as de-
scribed in 5.1.
NOTE It is recommended that an oblique astigmatism compensator is provided for observation and photography of
the periphery of the retina when using a fundus camera with an angular field-of-view of 30° or less.
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Table 1 — Requirements for optical properties
Criterion Minimum requirement
centre 80 lp/mm
< 30° middle (r/2) 60 lp/mm
Resolving power for periphery (r) 40 lp/mm
camera with centre 60 lp/mm
field of view > 30° middle (r/2) 40 lp/mm
periphery (r) 25 lp/mm
Tolerance of field of view + 7 %
Tolerance of magnification + 7 %
of photography
25 D to +5 D
Range of dioptre adjustment
24 D to +2 D
of the optical finder
for high eye point eyepieces
Range of focus adjustment for 215 D to +15 D
compensation of patient's refractive error
4.3 Construction and function
4.3.1 General
The instrument shall be designed in a way that there is no reflection nor stray light which is detrimental to the
photography.
4.3.2 High eye point eyepiece
If the manufacturer states that the eyepiece is a high eye point eyepiece, the clearance shall be a minimum of
17 mm, as measured from that part of the eyepiece nearest the examiner's eye to the exit pupil of the instrument.
4.4 Optical radiation hazard with fundus cameras
4.4.1 General
This clause replaces clauses 32, 33 and 34 of IEC 60601-1:1988.
The limit values given in items a) and b) of 4.4.2 shall apply to the radiation emerging from the fundus camera used
to illuminate and view the human eye with visible light (380 nm to 700 nm) and in which the full beam
homogeneously illuminates an 8 mm circular pupil (see notes 1 and 2 of 4.4.2).
NOTE The limit values given in 4.4.2 are considered acceptable with respect to the risks when weighted against the
performances intended.
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4.4.2 Limit values
a) Short wavelength limit:
The amount of radiant power exiting the fundus camera in the portion of the spectrum from 305 nm to 400 nm
2
shall have an irradiance no greater than 0,05 mW/cm as measured in the corneal plane when the instrument is
1)
operating at maximum intensity and, if the aperture can be varied, at maximum aperture.
b) Long wavelength limit:
The amount of energy exiting the fundus camera in the wavelength range 700 nm to 1100 nm shall not exceed
2
100 mW/cm nor shall it exceed the amount of energy exiting the fundus camera in the range between 380 nm
and 700 nm. The energy shall be measured in the corneal plane when the fundus camera is operating at
maximum intensity and maximum aperture.
NOTE 1 If due to stops or other obstructions of the beam, a circular pupil of less than 8 mm diameter is illuminated,
the limit values may be increased by the ratio of the area of an 8 mm diameter pupil divided by the true area
illuminated.
NOTE 2 It is recommended that the energy in the range of the spectrum below 420 nm be attenuated as much as
possible.
NOTE 3 For fundus cameras, when operated with non-pulsed radiation (in particular when using the alignment
illumination), the assumptions used to set the limit value for radiation of wavelength shorter than 400 nm are based on
considerations of the typical spectral distribution of a 3000 K standard black-body source, an illuminating solid angle at
the corneal plane of 0,031 sr, a maximum exposure time of 5 min and the weighting factors for L (see annex A). The
A
limit is set to ensure that the fraction of the photochemical hazard dose due to radiation of wavelength shorter than
400 nm is no greater than 1/8 of the total photochemical hazard dose over all wavelengths when that total dose is at
the threshold limit for an 8 mm diameter pupil.
Using the American Conference of Governmental Industrial Hygienists (ACGIH) guidelines, that threshold limit is
2
14 J/(cm ⋅ sr). To convert from photochemical hazard weighted radiance to irradiance, over the designated spectral
range 305 nm to 400 nm, the conversion factor 0,276 is used. Thus the limit is then found by the formula
2 2
[14 J/(cm ⋅ sr)] x (0,031 sr) x [0,276/(300s ⋅ 8)] = 0,05 mW/cm
2
NOTE 4 For fundus cameras, when operated with pulsed radiation, the limit is a total dose expressed in J/cm , and is
found by the formula
2 2
[14 J/(cm ⋅ sr)] x (0,031 sr) x (0,276/8) = 15 mJ/cm
2
For multiple pulses, the limit per pulse is then 15 mJ/cm divided by the number of pulses.
NOTE 5 Fundus cameras often have illuminating solid angles larger than Ω = 0,031 sr. If this is the case, the limit
values may be increased by the ratio of the true solid angle, expressed in steradians, divided by 0,031.
4.4.3 Variable brightness
For instruments where provision is made to vary the brightness, the manufacturer shall provide indications of the
proportions of the maximum intensity.
4.4.4 Particular information
The manufacturer shall provide the user with a graph showing the relative spectral output of the fundus camera
between 305 nm and 1100 nm when the instrument is operating at maximum intensity and maximum aperture. The
spectral output shall be shown for the beam after it exits the illumination system.
_______________________
1) Maximum intensity is the highest brightness the fundus camera is capable of delivering, including the highest intensity achievable if
overvoltage is provided.
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The manufacturer shall provide the user with the values for the spectrally-weighted photochemical source radiance,
both phakic (L ) and aphakic (L ), measured in the beam exiting from the instrument when operating at maximum
B A
intensity and maximum aperture and determined by using the spectral weighting values given in Annex A.
The manufacturer shall provide information on the meaning of L and L to the user.
B A
NOTE An example of such information is given in Annex B.
5 Test methods
All tests described in this International Standard are type tests.
5.1 Checking the optical requirements
The requirements specified in 4.2 shall be verified by use of measuring devices the measuring errors of which are
smaller than 10 % of the smallest value to be determined.
Test results shall be evaluated in accordance with general rules of statistics.
5.1.1 Checking the resolving power
The resolving power shall be
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