Ophthalmic optics and instruments - Optical and electro-optical devices for enhancing low vision (ISO 15253:2021)

Augenoptik und ophthalmische Instrumente - Optische und elektrooptische vergrößernde Sehhilfen für Sehbehinderte (ISO 15253:2021)

Dieses Dokument ist anwendbar für optische und elektrooptische Geräte, die vom Hersteller für die Verwendung durch sehbehinderte Personen als Sehhilfen vorgesehen sind. Dieses Dokument legt Anforderungen und Prüfverfahren für optische und elektrooptische Geräte fest, die vom Hersteller für die Verwendung durch sehbehinderte Personen als Sehhilfen vorgesehen sind.
Implantierbare Sehhilfen sind ausgenommen.

Optique et instruments ophtalmiques - Dispositifs optiques et électro-optiques pour malvoyants (ISO 15253:2021)

Očesna optika in instrumenti - Optične in elektrooptične naprave za izboljšanje slabovidnosti (ISO 15253:2021)

General Information

Status
Published
Technical Committee
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
14-Jul-2021
Completion Date
14-Jul-2021

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SLOVENSKI STANDARD
oSIST prEN ISO 15253:2020
01-december-2020
Očesna optika in instrumenti - Optične in elektrooptične naprave za izboljšanje
slabovidnosti (ISO/DIS 15253:2020)

Ophthalmic optics and instruments - Optical and electro-optical devices for enhancing

low vision (ISO/DIS 15253:2020)
Augenoptik und ophthalmische Instrumente - Optische und elektro-optische
vergrößernde Sehhilfen für Sehbehinderte (ISO/DIS 15253:2020)

Optique et instruments ophtalmiques - Dispositifs optiques et électro optiques pour

malvoyants (ISO/DIS 15253:2020)
Ta slovenski standard je istoveten z: prEN ISO 15253
ICS:
11.040.70 Oftalmološka oprema Ophthalmic equipment
oSIST prEN ISO 15253:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 15253:2020
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oSIST prEN ISO 15253:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 15253
ISO/TC 172/SC 7 Secretariat: DIN
Voting begins on: Voting terminates on:
2020-10-07 2020-12-30
Ophthalmic optics and instruments — Optical and electro-
optical devices for enhancing low vision
Optique et instruments ophtalmiques — Dispositifs optiques pour malvoyants
ICS: 11.040.70
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 15253:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
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oSIST prEN ISO 15253:2020
ISO/DIS 15253:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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

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ii © ISO 2020 – All rights reserved
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oSIST prEN ISO 15253:2020
ISO/DIS 15253:2020(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Classification ............................................................................................................................................................................................................ 9

4.1 Optical devices ........................................................................................................................................................................................ 9

4.1.1 Distance vision ...................................................................... ............................................................................................. 9

4.1.2 Near and intermediate vision ............................................................................................................................... 9

4.1.3 Retinal illumination reduction or contrast enhancement ............................................................ 9

4.2 Electro-optical devices ..................................................................................................................................................................... 9

5 Requirements .......................................................................................................................................................................................................... 9

5.1 General ........................................................................................................................................................................................................... 9

5.1.1 Risk assessment and management .................................................................................................................. 9

5.1.2 Materials ................................................................................................................................................................................. 9

5.1.3 Dimensions and weight ...........................................................................................................................................10

5.1.4 Flammability/Ignitability......................................................................................................................................10

5.1.5 Resistance to perspiration ....................................................................................................................................10

5.1.6 Robustness .........................................................................................................................................................................10

5.1.7 Resistance to drop .......................................................................................................................................................10

5.2 Optical devices .....................................................................................................................................................................................10

5.2.1 Spatial resolution .........................................................................................................................................................10

5.2.2 Equivalent power (applies to optical devices designed for near or

intermediate use) .........................................................................................................................................................11

5.2.3 Magnification ...................................................................................................................................................................11

5.2.4 Exit image distance (applies to stand magnifiers) ..........................................................................12

5.2.5 Entrance pupil diameter (applies to telescopes) ..............................................................................12

5.2.6 Transmittance .................................................................................................................................................................12

5.2.7 Image relocation ...........................................................................................................................................................12

5.3 Electro-optical devices ..................................................................................................................................................................12

5.3.1 Display size ........................................................................................................................................................................12

5.3.2 Ambient temperatures .................. ......................................................................................................................... ..12

5.3.3 Image characteristics ................................................................................................................................................12

5.3.4 Object (XY) table ...........................................................................................................................................................13

5.3.5 Working distance ..........................................................................................................................................................13

5.3.6 Text to speech ..................................................................................................................................................................13

5.3.7 Electrical requirements ..........................................................................................................................................13

6 Test methods ..........................................................................................................................................................................................................13

6.1 General ........................................................................................................................................................................................................13

6.2 Optical devices .....................................................................................................................................................................................14

6.2.1 Spatial resolution test ...............................................................................................................................................14

6.2.2 Equivalent power – Magnifiers .........................................................................................................................17

6.2.3 Angular magnification – Telescopes ............................................................................................................17

6.2.4 Transverse magnification – Stand magnifiers .....................................................................................17

6.2.5 Lateral variation of magnification test .......................................................................................................17

6.2.6 Exit image distance – Stand magnifiers ....................................................................................................18

6.3 Electro-optical devices ..................................................................................................................................................................18

6.3.1 Display magnification test ....................................................................................................................................18

6.3.2 Uniformity of magnification ................................................................................................................................18

7 Information to be provided by the manufacturer ...........................................................................................................18

7.1 Marking ......................................................................................................................................................................................................18

7.2 Instructions for use ..........................................................................................................................................................................18

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7.2.1 General...................................................................................................................................................................................18

7.2.2 Optical devices ................................................................................................................................................................19

7.2.3 Electro-optical devices.............................................................................................................................................19

Annex A (informative) Determination of lateral variation of magnification ...........................................................20

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oSIST prEN ISO 15253:2020
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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 (see 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 (see 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.

For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following

URL: www .iso .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee

SC 7, Ophthalmic optics.

This edition cancels and replaces the first edition (ISO 15253:2000) and the second edition of ISO 15254

(ISO 15254:2009), which both have been technically revised.
The main changes compared to the previous edition are as follows:
— merger of ISO 15253 and ISO 15254;
— revision of normative references;
— revision and re-organisation of terms and definitions;

— addition of new requirements for filters and tints, image relocation, and text to speech;

— editorial revision of the document.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
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Introduction

This document represents the merger of two earlier related standards for low vision devices – one for

optical devices only (previous ISO 15253) and another for electro-optical devices (ISO 15254) – and

updating of terms, definitions, and requirements. It also includes new requirements for

— filters and tints, such as for users with extreme light sensitivity or reduced contrast sensitivity,

independent of visual acuity or visual field loss;

— image relocation, such as with prisms or mirrors for users with visual field loss or eye- or head-

movement restriction; and
— text to speech for electro-optical devices that offer such capability.

The reader is reminded that the requirements within this document apply to the manufacturer of low

vision devices. While the requirements can also pertain to how a particular device will function for the

low vision user, some factors and variables about the user may not be known to the manufacturer and

thus specific requirements cannot be made. For example, the system resolution of an electro-optical

device is governed by pixel size and density for both the camera and display, while the spatial resolution

for the user depends on the size of the display and the distance at which the user views the display.

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oSIST prEN ISO 15253:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 15253:2020(E)
Ophthalmic optics and instruments — Optical and electro-
optical devices for enhancing low vision
1 Scope

This document applies to optical and electro-optical devices specified by the manufacturer for use by

visually impaired persons as low vision aids. This document contains requirements and test methods

for optical and electro-optical devices specified by the manufacturer for use by visually impaired

persons as low vision devices.
Implanted low vision devices are excluded.
2 Normative references

The following documents are referred to in the text in such a way that some or all of 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.

EN 55022, Information technology equipment — Radio disturbance characteristics — Limits and methods

of measurement (IEC/CISPR 22:2005, modified + A1: 2005)

EN 60950-1, Information technology equipment — Safety — Part 1: General requirements

ISO 12312-1, Eye and face protection — Sunglasses and related eyewear — Part 1: Sunglasses for general use

ISO 12870, Ophthalmic optics — Spectacle frames — Requirements and test methods

ISO 14889, Ophthalmic optics — Spectacle lenses — Fundamental requirements for uncut finished lenses

ISO 14971, Medical devices — Application of risk management to medical devices

ISO 15004-1, Ophthalmic instruments — Fundamental requirements and test methods — Part 1: General

requirements applicable to all ophthalmic instruments

ISO 15004-2, Ophthalmic instruments — Fundamental requirements and test methods — Part 2: Light

hazard protection

IEC 60601-1, Medical electrical equipment — Part 1: General requirements for basic safety and essential

performance

IEC 60601-1-2, Medical electrical equipment — Part 1-2: General requirements for basic safety and essential

performance — Collateral standard: Electromagnetic disturbances — Requirements and tests

IEC 60601-1-3, Medical Electrical Equipment — Part 1-3: General Requirements for Basic Safety And

Essential Performance — Collateral Standard: Radiation Protection In Diagnostic X-Ray Equipment

IEC 60695-2-11, Fire Hazard Testing — Part 2-11: Glowing/Hot-Wire Based Test Methods — Glow-Wire

Flammability Test Method for End-Products (GWEPT)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org
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— ISO Online browsing platform: available at https:// www .iso .org/ obp
3.1
low vision device
apparatus that alters or enhances the image viewed by a person having low vision
3.1.1
optical low vision device

lens or lens system, prism, or mirror, or combination of such optical components, that alters image

characteristics, such as vergence, size, and/or position

Note 1 to entry: Image relocation using a prism, whether ground in or temporary (e.g., Fresnel), is commonly

expressed in centimetres per metre or prism dioptres.

Note 2 to entry: Image relocation using a mirror is commonly expressed in degrees.

3.1.2
electro-optical low vision device
opto-electronic low vision device

device or system that produces an altered or enhanced image through the interaction between light

from the object and an electronic system

Note 1 to entry: The device minimally consists of a camera and a monitor or display, but can contain additional

components such as a computer, display control interface, projector, speakers, tactile output, narrow-beam light

source, scanner, and software.

Note 2 to entry: In addition to computer-based systems, common configurations and terms for electro-optical

low vision devices are video magnifier and closed-circuit television (CCTV), with which the image is displayed or

projected at some distance removed from the user’s spectacle plane, and head-mounted (a.k.a. head-up) display,

with which the image is presented on a display at or near the user’s spectacle plane or projected directly into the

user’s eye.
3.1.3
filter
tinted lens

optical component that absorbs and/or reflects light in order to reduce the amount of light transmitted

to the user’s eye
3.1.3.1
neutral density filter

filter designed to reduce the amount of light by the same percentage for each wavelength across the

visible spectrum
3.1.3.2
coloured tint

filter that selectively reduces the amount of light transmitted for some wavelengths relative to that

transmitted for other wavelengths

Note 1 to entry: Examples of coloured tints include cut-off, bandpass, and notch filters.

3.2
magnification

ratio between a dimension of the image when a low vision device is in use and the corresponding

dimension when the object is viewed without the device
Note 1 to entry: Dimension can be angular or linear.
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3.2.1
angular magnification

ratio of the angle subtended by the image of the object when viewed using a low vision device to the

angle subtended by the object alone at a viewing point of reference, such as the entrance pupil of the eye

Note 1 to entry: Angular magnification is used primarily for afocal telescopic low vision devices. It also applies in

part to magnifiers that are positioned at distances removed from the spectacle plane.

3.2.2
retinal image magnification

total magnification that is obtained when using a low vision device and/or viewing technique, calculated

as the product of the angular, relative distance, and relative size magnifications.

Note 1 to entry: Viewing techniques include changing viewing distance (i.e., relative distance magnification) and

changing font or object size (i.e., relative size magnification). Depending on the low vision device and how it is

used, a specific change can result in an increase or decrease in image size compared to that dimension when the

device is not used.
3.3
magnifier
lens system designed to change the size of the image of a near object

Note 1 to entry: The magnifier may be a simple single element or a compound multiple-element system.

3.3.1
hand magnifier
hand-held magnifier

magnifier intended to be positioned and supported by the user's hand and without artificial support

3.3.2
stand magnifier

magnifier in which a support positions the optical system at a fixed or adjustable distance from the

object to be viewed
3.3.3
head-mounted magnifier
magnifier mounted in a device that is supported on the head
3.3.4
spectacle-mounted magnifier
magnifier mounted in a device that attaches to a spectacle frame
3.3.5
spectacle magnifier
spectacle microscope

spectacle lenses having greater power for near focus than found in typical spectacle corrections,

creating retinal image magnification primarily by allowing for relative distance magnification

Note 1 to entry: In addition to relative distance magnification, some usually small amount of magnification can

result from the parameters of the lens, such as base curve, centre thickness, and refractive index.

3.4
telescope

optical system composed of two separated lenses (or lens systems), the objective and the eyepiece, that

forms a magnified image of a distant object when the eyepiece is the higher powered lens (or system)

Note 1 to entry: In its afocal adjustment, the second (back) focal point of the objective lies at the first (front)

focal point of the eyepiece, so that light from a distant object, entering the objective with zero vergence, exits the

eyepiece with zero vergence. This is the condition for a user wearing full correction for refractive error viewing a

very distant object clearly through the telescope.
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Note 2 to entry: A telescope provides angular magnification, which in its afocal adjustment can be calculated by

the negative of the ratio of the equivalent power of the eyepiece to the equivalent power of the objective.

3.4.1
entrance pupil diameter
clear aperture of the telescopic objective
Note 1 to entry: Entrance pupil diameter is expressed in millimetres.
3.4.2
focusable telescope

telescope for which the separation between the objective and eyepiece can be changed to compensate

for a range of object distances and/or to compensate for uncorrected spherical refractive error

3.5
telemicroscope
near-vision telescope
telescope adapted for viewing near or intermediate objects
3.5.1
reading cap

positive optical element placed in front of the telescopic objective to adapt the device for viewing a near

or intermediate object
Note 1 to entry: Reading cap power is expressed in dioptres.

Note 2 to entry: In a fixed-focus afocal telescope, the reading cap is a removable lens.

Note 3 to entry: In a fixed-focus telemicroscope, the reading cap is incorporated into the objective power.

Note 4 to entry: In a focusable telescope, a portion of the objective power functions as the reading cap. This

reduces the objective power that remains, thus creating a “new” afocal telescope with slightly greater angular

magnification.
3.6
field expander
reverse telescope
minifier

device that reduces the apparent field of view so that it is smaller than the user’s unaided field of view

Note 1 to entry: Apparent field of view is the angle subtended by the field as viewed through a telescope.

3.7
spatial resolution

smallest separation between two details in the object for which they can be recognised as being

separate under a given set of conditions
3.8
field of view
extent of the object plane visible through, or imaged by, a device

Note 1 to entry: See entries below for definitions of field of view for specific types of devices.

3.8.1
resolvable field of view
field of view within which the device is capable of resolving required details
3.9 Parameters for magnifiers
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3.9.1
optical dimensions
zone of optical dimensions
optical zone of magnifier
linear size of the lens of a magnifier that is visible when mounted
Note 1 to entry: Optical dimensions are expressed in millimetres.
3.9.2
optical axis

line connecting the centres of curvature of the surfaces of an optical system, along which there is

symmetry and zero induced prism
3.9.3
equivalent focal length

distance between a focal point and the corresponding principal plane, measured along the optical axis

SEE: Figure 1.

Note 1 to entry: First focal length is measured from the first principal plane to the first (front) focal point.

Note 2 to entry: Second focal length is measured from the second principal plane to the second (back) focal point.

3.9.4
equivalent power
reciprocal of the equivalent focal length in air measured in metres

Note 1 to entry: Equivalent power is expressed in dioptres, or reciprocal metres.

Key
1 first focal length F first (front) focal point
2 second focal length F’ second (back) focal point
H first principal plane
H’ second principal plane
Figure 1 — Illustration of focal lengths
3.9.5
working distance
distance between the front vertex of the magnifier and the object being viewed
SEE: Figure 2.
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3.9.6
exit image distance
vertex image distance

distance between the back vertex of the magnifier and the virtual image formed by the magnifier when

the object is placed in the designated position
SEE: Figure 2.
Note 1 to entry: Exit image distance is especially useful for stand magnifiers.
3.9.7
viewing distance

distance between the image formed by the magnifier and the spectacle plane of the user

SEE: Figure 2.
Key
1 object plane y object size
2 image plane y’ image size
3 spectacle plane
4 working dis
...

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