EN ISO 15253:2000
(Main)Ophthalmic optics and instruments - Optical devices for enhancing low vision (ISO 15253:2000)
Ophthalmic optics and instruments - Optical devices for enhancing low vision (ISO 15253:2000)
Migrated from Progress Sheet (TC Comment) (2000-07-10): Contact Mr Vyze ext 850 when processing this project through each stage
Augenoptik und ophthalmische Instrumente - Vergrößernde Sehhilfen für Sehbehinderte (ISO 15253:2000)
Diese Internationale Norm gilt für optische Geräte, die vom Hersteller zur Verwendung durch sehbehinderte Personen als optische Sehhilfen vorgesehen sind. Sie legt optische und mechanische Anforderungen und Prüfverfahren fest. Sie gilt auch für optische Vorrichtungen mit elektrischen Komponenten, wie z.B. Beleuchtungen. Diese Internationale Norm gilt nicht für elektrooptische Sehhilfen für Sehbehinderte. ANMERKUNG: Anforderungen und Prüfverfahren für elektrooptische Sehhilfen für Sehbehinderte sind in ISO 15254 "Ophthalmic optics and instruments - Elektro-optical devices for low vision" festgelegt.
Optique et instruments ophtalmiques - Dispositifs optiques pour malvoyants (ISO 15353:2000)
La présente Norme internationale s'applique aux dispositifs optiques qui, selon les indications du fabricant, sont destinés à être utilisés par des personnes malvoyantes comme systèmes d'aide à la vision. Elle spécifie des exigences optiques et mécaniques, ainsi que des méthodes d'essai, et inclut les dispositifs optiques avec composants électriques, tels que des sources lumineuses. La présente Norme internationale ne s'applique pas aux dispositifs électro-optiques pour malvoyants. NOTE: Les exigences et les méthodes d'essai relatives aux dispositifs électro-optiques pour malvoyants figurent dans l'ISO 15254, Optique et instruments ophtalmiques - Dispositifs étectro-optiques pour malvoyants.
Očesna optika in instrumenti - Optične naprave za izboljšanje slabovidnosti (ISO 15253:2000)
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
01-november-2001
2þHVQDRSWLNDLQLQVWUXPHQWL2SWLþQHQDSUDYH]DL]EROMãDQMHVODERYLGQRVWL ,62
Ophthalmic optics and instruments - Optical devices for enhancing low vision (ISO
15253:2000)
Augenoptik und ophthalmische Instrumente - Vergrößernde Sehhilfen für Sehbehinderte
(ISO 15253:2000)
Optique et instruments ophtalmiques - Dispositifs optiques pour malvoyants (ISO
15353:2000)
Ta slovenski standard je istoveten z: EN ISO 15253:2000
ICS:
11.040.70 Oftalmološka oprema Ophthalmic equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
INTERNATIONAL ISO
STANDARD 15253
First edition
2000-09-15
Ophthalmic optics and instruments —
Optical devices for enhancing low vision
Optique et instruments ophtalmiques — Dispositifs optiques pour
malvoyants
Reference number
ISO 15253:2000(E)
©
ISO 2000
ISO 15253:2000(E)
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ii © ISO 2000 – All rights reserved
ISO 15253:2000(E)
Contents Page
Foreword.iv
1 Scope .1
2 Normative references .1
3 Terms and definitions .1
4 Classification.6
4.1 Magnifiers.6
4.2 Telescopes — Distance vision .6
4.3 Telescopes — Near-vision/telemicroscopes .6
4.4 Telescopes — Adjustable .6
5 Requirements.6
5.1 Optical characteristics .6
5.2 Materials and construction.8
6 Environmental conditions of use.8
7 Test methods.9
7.1 General.9
7.2 Equivalent power — Magnifiers .9
7.3 Angular magnification — Telescopes.9
7.4 Resolution test.9
7.5 Determination of lateral variation of magnification.13
8 Marking and instructions for use.13
8.1 Marking .13
8.2 Information to be provided by the manufacturer .13
Annex A (informative) Determination of lateral variation of magnification.14
Annex B (informative) List of equivalent terms.19
ISO 15253:2000(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
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.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 15253 was prepared by Technical Committee ISO/TC 172, Optics and optical
instruments, Subcommittee SC 7, Ophthalmic optics and instruments.
Annexes A and B of this International Standard are for information only.
iv © ISO 2000 – All rights reserved
INTERNATIONAL STANDARD ISO 15253:2000(E)
Ophthalmic optics and instruments — Optical devices for
enhancing low vision
1 Scope
This International Standard applies to optical devices specified by the manufacturer for use by visually impaired
persons as optical low-vision aids. It specifies the optical and mechanical requirements and test methods for such
devices, including optical devices with electrical components such as illuminators.
It does not apply to electro-optical devices for enhancing low vision.
NOTE Requirements and test methods for electro-optical devices for enhancing low vision are specified in ISO 15254,
Ophthalmic optics and instruments — Electro-optical devices for low vision.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 12870, Ophthalmic optics — Spectacle frames — General requirements and test methods.
ISO 14889, Ophthalmic optics — Spectacle lenses — Fundamental requirements for uncut finished lenses.
ISO 15004:1997, Ophthalmic instruments — Fundamental requirements and test methods.
3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply. The symbols for certain of
these terms are language-dependent. Equivalent terms in other languages, and the corresponding symbols used in
those languages as well as in English, are given in annex B.
3.1
astronomical telescope
Keplerian telescope
compound optical system, afocal in normal adjustment, consisting of a positive objective element or group and a
positive ocular element or group forming a magnified, inverted image
3.2
binocular aid
optical device, usually consisting of two separate optical systems mounted in alignment, intended to be used with
both eyes simultaneously
3.3
biocular aid
optical device in which both eyes view through a single optical system
ISO 15253:2000(E)
3.4
distance cap
negative lens placed in front of a near-vision telescope/telemicroscope objective to adapt the device for viewing a
distant object
3.5
equivalent power
reciprocal of the equivalent focal length in air measured in metres
NOTE Equivalent power is expressed in dioptres, or reciprocal metres.
3.6
eyepiece
ocular
optical element or group nearest to the eye in an optical imaging system, used for viewing the image formed by the
objective
3.7
focal length
linear distance separating the principal focal point (or focus) of an optical system from a point of reference
SeeFigure1.
NOTE The distance needs to be further specified in accordance with the point of reference chosen, e.g. vertex, principal
point. See definitions 3.7.1 to 3.7.3.
3.7.1
back vertex focal length
distance in an optical system from the back surface to the back focal point, measured along the optical axis (axis of
symmetry)
SeeFigure1.
3.7.2
front vertex focal length
distance in an optical system from the front surface to the front focal point, measured along the optical axis (axis of
symmetry)
SeeFigure1.
3.7.3
equivalent focal length
distance in an optical system from a focal point to the corresponding principal point, measured along the optical
axis (axis of symmetry)
SeeFigure1.
NOTE See equivalent power (3.5).
3.8
focusing telescopic device
device intended to be adjusted by the user for a range of object distances
3.9
free working distance
�optical low vision aid� distance between the most anterior portion of a near-vision telescope/telemicroscope and
the object
2 © ISO 2000 – All rights reserved
ISO 15253:2000(E)
Key
1 Front vertex focal length
2 Back vertex focal length
3 Focal length
4 Equivalent focal length
Figure 1 — Illustration of focal lengths
3.10
Galilean telescope
compound optical system, afocal in normal adjustment, consisting of a positive objective element or group and a
negative ocular element or group forming a magnified, erect image
3.11
hand magnifier
device intended to be positioned and supported by the user's hand and without artificial support
3.12
linear field of view
�of a low vision aid� maximum observable extent of the object plane visible through the low vision aid under the
conditions of use stated by the manufacturer
3.13
low vision aid
device used by visually impaired persons to enhance vision
3.14
low vision-aid telescope
optical system, Keplerian with inverted image or Galilean, that forms a magnified retinal image of an object
3.14.1
hand telescope
telescope designed to be hand-held
3.14.2
spectacle telescope
telescope mounted in or on a spectacle frame
3.15
magnification
ratio between any linear dimension of the retinal image when the magnifying device is in use and the
corresponding dimension when the object is viewed without the magnifying device
ISO 15253:2000(E)
3.15.1
angular magnification
ratio of the angle subtended by the image to that subtended by the object at a viewing point of reference such as
the entrance pupil of the eye
3.15.2
nominal magnification
M
�for magnifiers� magnification calculated from the product of the reference seeing distance (see 3.20), in metres,
and the equivalent power F (see 3.5), in dioptres
EXAMPLE With a reference seeing distance of 0,25 m the nominal magnification is calculated from the formula
M=0,25 F.
3.15.3
trade magnification (deprecated)
M
trade
�for magnifiers� magnification calculated from the formula:
M = M +1
trade
NOTE This definition is included since some text books on low vision refer to trade magnification. This term should not be
used in future.
3.16
magnifier
low vision-aid microscope
lens system designed to produce an enlarged image
NOTE It may be a simple single element or a compound multiple-element system.
3.
...
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