EN ISO 9338:1998
(Main)Optics and optical instruments - Contact lenses - Determination of the diameters (ISO 9338:1996)
Optics and optical instruments - Contact lenses - Determination of the diameters (ISO 9338:1996)
Specification of a uniform test procedure in order to achieve comparable test results.
Optik und optische Instrumente - Kontaktlinsen - Bestimmung der Durchmesser (ISO 9338:1996)
Diese Internationale Norm legt die Verfahrensweise für die Bestimmung des Durchmessers von Kontaktlinsen fest. Anhang A beschreibt ein Projektionsverfahren, das sowohl für weiche als auch für hartflexible Kontaktlinsen geeignet ist. Anhang B beschreibt ein Verfahren, das nur für hartflexible Kontaktlinsen geeignet ist.
Optique et instruments d'optique - Lentilles de contact - Détermination des diamètres (ISO 9338:1996)
Optika in optični instrumenti - Kontaktne leče - Ugotavljanje premerov (ISO 9338:1996)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 9338:2000
01-januar-2000
2SWLNDLQRSWLþQLLQVWUXPHQWL.RQWDNWQHOHþH8JRWDYOMDQMHSUHPHURY ,62
Optics and optical instruments - Contact lenses - Determination of the diameters (ISO
9338:1996)
Optik und optische Instrumente - Kontaktlinsen - Bestimmung der Durchmesser (ISO
9338:1996)
Optique et instruments d'optique - Lentilles de contact - Détermination des diametres
(ISO 9338:1996)
Ta slovenski standard je istoveten z: EN ISO 9338:1998
ICS:
11.040.70 Oftalmološka oprema Ophthalmic equipment
SIST EN ISO 9338:2000 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 9338:2000
INTERNATIONAL ISO
STANDARD 9338
First edition
1996-l O-l 5
Optics and optical instruments - Contact
lenses - Determination of the diameters
Optique et instruments d’optique - Len Mes de con tact - Détermination
des diamètres
Reference number
ISO 9338:1996(E)
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SIST EN ISO 9338:2000
ISO 9338: 1996(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 9338 was prepared by Technical Committee
ISORC 172, Optics and optical instruments, Subcommittee SC 7,
Oph thalmic op tics and instruments.
Annex A forms an integral part of ISO 9338. Annex B is for information
only.
0 60 1996
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 l CH-l 211 Genève 20 8 Switzerland
Printed in Switzerland
ii
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SIST EN ISO 9338:2000
ISO 9338: 1996(E)
INTERNATIONAL STANDARD @ Iso
Contact lenses -
Optics and optical instruments -
Determination of the diameters
1 Scope
This International Standard describes methods for the determination of contact lens diameters.
Annex A describes a projection method which is suitable for both soft and rigid contact lenses. Annex B describes
a method which is suitable only for rigid contact lenses.
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 edition indicated was 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 8320:1986, Optics and optical instruments - Contact lenses - Vocabulary and symbols
ISO 10344:1996, Optics and optical instruments - Contact lenses - Saline solution for con tact lens tes ting.
BS 3625:1963 (1994), Specification for eyepiece and screen graticules for the determination of the particle size of
powders.
BS 3406 Part 4:1993, Methods for determination of particle size distribution - Guide to microscope and image
analysis methods.
3 Definitions
For the purposes of this International Standard, the definitions given in ISO 8320 apply.
4 Requirements
4.1 Measuring precision
The minimum reproducibility shall be k 0,05 mm.
1
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4.2 Measuring temperature
The measurements shall be done at a temperature in the range of 18 OC to 35 OC. The chosen measuring
temperature shall be stated in the test report.
5 Test report
The test report shall contain at least the following information:
a) the identification of the contact lens tested;
b) a reference to this International Standard;
c) the measuring temperature;
d) the diameter of the contact lens;
e) the date of the measurements.
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Annex A
(normative)
Determination of diameter of a contact lens using the projection method
A. 1 Principle
The diameter of the lens is determined from an enlarged projection of the lens on a screen in comparison with a
calibrated scale.
A.2 Apparatus and reagents
A.2.1 Projection system
The projection system, as shown in figure A.1 shall be capable of measuring to + 0,05 mm over a range of 0 mm to
17 mm.
S: Observing screen with scale
M: Mirror
_----------------------
XT )-- i d-0: Diaphragm
8
0: Objective
CL: Contact Lens
test specimen
CV: Contact lens
-
support (cuvette)
C: Condenser
+-
/
8
L: Light source
,
Figure A. 1 - Principle of the apparatus
The contact lens support CV is placed horizontally and cari be adjusted vertically. The scale of the screen S
represents a linear magnification of at least x 15 and permits a measurement accuracy of 0,05 mm for the contact
lens diameter. The apparatus has a telecentric path of rays which is ensured by positioning the diaphragm D in the
rear focal plane of the objective 0.
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ISO 9338: 1996(E)
A.2.2 Test graticule
A microscope graticule as specified in BS 3625, or an equivalent graticule with a diameter of at least 15 mm shall
be used for calibration as recommended in BS 3406 Part 4.
A.2.3 Reagent
Conditioning and measurement of soft contact lenses shall be made in saline solution as specified in ISO 10344.
A.3 Conditioning
A.3.1 For hydrogel lenses, each contact lens shall be fully hydrated and stabilized in saline solution The
measuring solution and the contact lens shall be stabilized before the test and maintained during the
...
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