EN ISO 11979-3:2006

SLOVENSKI STANDARD
01-julij-2006
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SIST EN 13503-3:2000
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Ophthalmic implants - Intraocular lenses - Part 3: Mechanical properties and test
methods (ISO 11979-3:2006)
Ophthalmische Implantate - Intraokularlinsen - Teil 3: Mechanische Eigenschaften und
Prüfverfahren (ISO 11979-3:2006)
Implants ophtalmiques - Lentilles intraoculaires - Partie 3: Propriétés mécaniques et
méthodes d'essai (ISO 11979-3:2006)
Ta slovenski standard je istoveten z: EN ISO 11979-3:2006
ICS:
11.040.70
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 11979-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2006
ICS 11.040.70 Supersedes EN 13503-3:2000
English Version
Ophthalmic implants - Intraocular lenses - Part 3: Mechanical
properties and test methods (ISO 11979-3:2006)
Implants ophtalmiques - Lentilles intraoculaires - Partie 3: Ophthalmische Implantate - Intraokularlinsen - Teil 3:
Propriétés mécaniques et méthodes d'essai (ISO 11979- Mechanische Eigenschaften und Prüfverfahren (ISO
3:2006) 11979-3:2006)
This European Standard was approved by CEN on 13 April 2006.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11979-3:2006: E
worldwide for CEN national Members.

Foreword
This document (EN ISO 11979-3:2006) has been prepared by Technical Committee ISO/TC 172
"Optics and optical instruments" in collaboration with Technical Committee CEN/TC 170
"Ophthalmic optics", the secretariat of which is held by DIN.

This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by November 2006, and conflicting national
standards shall be withdrawn at the latest by November 2006.

This document supersedes EN 13503-3:2000.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

Endorsement notice
The text of ISO 11979-3:2006 has been approved by CEN as EN ISO 11979-3:2006 without any
modifications.
INTERNATIONAL ISO
STANDARD 11979-3
Second edition
2006-05-01
Ophthalmic implants — Intraocular
lenses —
Part 3:
Mechanical properties and test methods
Implants ophtalmiques — Lentilles intraoculaires —
Partie 3: Propriétés mécaniques et méthodes d'essai

Reference number
ISO 11979-3:2006(E)
©
ISO 2006
ISO 11979-3:2006(E)
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ii © ISO 2006 – All rights reserved

ISO 11979-3:2006(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Requirements . 1
4.1 General. 1
4.2 Tolerances and dimensions . 2
4.3 Clearance analysis. 2
4.4 Compression force . 2
4.5 Axial displacement in compression. 3
4.6 Optic decentration . 3
4.7 Optic tilt . 3
4.8 Angle of contact. 3
4.9 Compression force decay. 3
4.10 Dynamic fatigue durability. 3
4.11 Surgical manipulation . 4
4.12 Surface and bulk homogeneity . 4
5 Recovery of properties following simulated surgical manipulation . 4
Annex A (normative) Measurement of compression force. 5
Annex B (normative) Measurement of axial displacement in compression . 9
Annex C (normative) Measurement of optic decentration. 12
Annex D (normative) Measurement of optic tilt . 15
Annex E (normative) Measurement of angle of contact. 18
Annex F (normative) Testing of compression force decay. 21
Annex G (normative) Testing of dynamic fatigue durability. 22
Annex H (informative) Measurement of loop pull strength. 24
Annex I (informative) Clearance analysis . 26
Annex J (informative) Precision.29
Bibliography . 30

ISO 11979-3:2006(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 2.
The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 11979-3 was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee SC 7,
Ophthalmic optics and instruments.
This second edition cancels and replaces the first edition (ISO 11979-3:1999), which has been technically
revised.
ISO 11979 consists of the following parts, under the general title Ophthalmic implants — Intraocular lenses:
⎯ Part 1: Vocabulary
⎯ Part 2: Optical properties and test methods
⎯ Part 3: Mechanical properties and test methods
⎯ Part 4: Labelling and information
⎯ Part 5: Biocompatibility
⎯ Part 6: Shelf-life and transport stability
⎯ Part 7: Clinical investigations
⎯ Part 8: Fundamental requirements
⎯ Part 9: Multifocal intraocular lenses
⎯ Part 10: Phakic intraocular lenses

iv © ISO 2006 – All rights reserved

ISO 11979-3:2006(E)
Introduction
This part of ISO 11979 contains methods for which requirements are given and methods for which no
requirements are formulated. The former are considered essential for the safety or performance of the
intraocular lens, while the latter provide essential information to the ophthalmic surgeon or are used for other
purposes.
A special purpose is the use of mechanical data to assess the need for clinical investigation of modifications of
[7]
existing models as described in ISO 11979-7 . Because of the complexity of this analysis, detailed
[8]
descriptions and examples have been given in ISO/TR 22979 . Due to the wide variety of intraocular lens
designs already on the market, it has not been possible to devise test methods that are applicable to every
design under all circumstances. It can be anticipated that new materials currently under development will
result in drastically new designs that will require modified or other test methods. As with all standards, it is
then up to the parties using the standard to modify or develop corresponding methods, and give rationale and
validation for them in a spirit that is consistent with this part of ISO 11979.
In cases where different tolerances have been given depending on material or design, they reflect an existing
situation with well-established products.

INTERNATIONAL STANDARD ISO 11979-3:2006(E)

Ophthalmic implants — Intraocular lenses —
Part 3:
Mechanical properties and test methods
1 Scope
This part of ISO 11979 specifies requirements and test methods for certain mechanical properties of
intraocular lenses (IOLs).
It is applicable to all types of IOLs intended for implantation in the anterior segment of the human eye,
excluding corneal implants, provided that the test method is appropriate to the particular IOL design.
2 Normative references
The following referenced documents are indispensable for the application 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 11979-1, Ophthalmic implants — Intraocular lenses — Part 1: Vocabulary
ISO 11979-2, Ophthalmic implants — Intraocular lenses — Part 2: Optical properties and test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11979-1 apply.
4 Requirements
4.1 General
For all IOLs, the mechanical properties shall be determined at in situ conditions. The precise composition of
the solution used shall be reported in all cases. Alternative test conditions, e.g. room temperature conditions,
may be used if a justification to deviate from in situ is given. The alternative test conditions shall be specified
in the test reports.
For each of the methods described below, tests shall be performed on a minimum of three IOL lots of medium
dioptric power. If dioptric power affects the property tested, the lots shall comprise one each of low, medium
and high dioptric powers. The minimum sample size for each test shall be 10 IOLs per lot. The lots shall be
representative of IOLs being marketed. In all cases, the sampling criteria applied shall be reported. Means
and standard deviations shall be reported for the pooled samples.
If, for certain designs and certain applications, a specific test method described in this part of ISO 11979 is not
applicable, the IOL manufacturer can devise a corresponding test method and provide a validation and
rationale for it.
ISO 11979-3:2006(E)
4.2 Tolerances and dimensions
For all types of IOLs except multipiece posterior chamber IOLs, the tolerance on the overall diameter shall be
± 0,20 mm. For multipiece posterior chamber IOLs, the tolerance on the overall diameter shall be ± 0,30 mm.
The tolerance on the vault height shall be as follows:
a) for anterior chamber IOLs, ± 0,15 mm;
b) for multipiece posterior chamber IOLs, ± 0,35 mm;
c) for other IOLs, ± 0,25 mm.
The tolerance on the sagitta shall be as follows:
⎯ for anterior chamber IOLs, ± 0,25 mm;
⎯ for multipiece posterior chamber IOLs, ± 0,45 mm;
⎯ for other IOLs, ± 0,35 mm.
The tolerance on the clear optic shall be ± 0,15 mm. The diameter of the clear optic shall be greater than
4,25 mm in any meridian. The tolerance on the dimensions of the body shall be ± 0,10 mm. For ellipsoid IOLs,
the dimensions of the body shall be reported as (short axis) × (long axis).
+0,05
The tolerance on the diameter of the positioning hole shall be nominal ( ) mm.
Dimensions for which tolerances are given above shall be specified in the manufacturer's design
documentation. Some dimensions may vary with dioptric power, hence different specifications may apply to
individual powers of an intraocular lens design.
4.3 Clearance analysis
An empirical analysis of anatomic placement shall be performed for anterior chamber lenses to evaluate the
most proximate points with relation to the anatomical structures of the eye. The clearance of the anterior
surface of the IOL optic in relation to the endothelial layer of the cornea shall be determined for the lens at its
minimum recommended diameter in its compressed state. The separation of the posterior surface of the IOL
optic to the iris as well as if phakic to the crystalline lens shall be determined. These results shall be
considered in the risk analysis. The theoretical eye model in Annex I can be used in the evaluation.
The manufacturer should strive for a clearance of at least 1 mm under worst-case conditions, i.e. conditions
which would result in the minimum amount of clearance.
4.4 Compression force
Using the method described in Annex A, the compression force shall be measured and reported as follows:
a) for IOLs intended for capsular bag placement, with the haptics compressed to a diameter of 10 mm;
b) for IOLs intended for sulcus placement, with the haptics compressed to a diameter of 11 mm;
c) for IOLs intended for both capsular bag and sulcus placement, with the haptics compressed to both a
diameter of 10 mm and a diameter of 11 mm;
d) for anterior chamber IOLs, with the haptics compressed to the minimum and maximum intended
compressed diameters recommended by the manufacturer in the product literature.
2 © ISO 2006 – All rights reserved

ISO 11979-3:2006(E)
4.5 Axial displacement in compression
Using the method described in Annex B, the axial displacement in compression shall be measured and
reported at the same diameters that were used for the measurement of compression force (see 4.4).
In addition, for anterior chamber IOLs, the vault height and the sagitta in the compressed state shall be given
in the product literature as a function of dioptric power at the minimum and maximum intended compressed
diameters, as specified in 4.4.
4.6 Optic decentration
Using the method described in Annex C, the optic decentration shall be measured and reported at the same
diameters that were used for the measurement of compression force (see 4.4).
The sum of the arithmetic mean and two standard deviations of the optic decentration shall not exceed 10 %
of the clear optic.
4.7 Optic tilt
Using the method described in Annex D, the optic tilt shall be measured and reported at the same diameters
that were used for the measurement of compression force (see 4.4).
The sum of the arithmetic mean and two standard deviations of the optic tilt shall not exceed 5°.
4.8 Angle of contact
Using the method described in Annex E, the angle of contact shall be measured and reported at the same
diameters that were used for the measurement of compression force (see 4.4).
NOTE The angle of contact is a measured approximation of the total haptic contact with the supporting ocular tissue.
4.9 Compression force decay
Using the method described in Annex F, the compression force decay shall be tested and reported at the
same diameters that were used for the measurement of compression force (see 4.4).
The loops of IOLs are designed to exert some pressure on eye structures as a means of keeping the IOL in
position and should continue to do so for some time after implantation.
Results shall be reported as residual compression force after 24 h ± 2 h in compression at each required
compressed diameter.
4.10 Dynamic fatigue durability
All loops shall be capable of withstanding, without breaking, 250 000 cycles of near-sinusoidal deformation of
± 0,25 mm around the compressed distance.
Using the method described in Annex G, fatigue testing shall be performed as follows:
a) for IOLs intended for capsular bag placement, at a compressed distance of 5,0 mm between the testing
plate and the centre of the optic;
b) for IOLs intended for sulcus placement, at a compressed distance of 5,5 mm between the testing plate
and the centre of the optic;
c) for IOLs intended for both capsular bag and sulcus placement, at a compressed distance of 5,0 mm
between the testing plate and the centre of the optic;
ISO 11979-3:2006(E)
d) for anterior chamber IOLs, at a distance between the testing plate and the centre of the optic,
corresponding to half the maximum intended compressed diameter as recommended by the
manufacturer in the product literature.
This test shall be carried out only for IOL designs in which the loop will be in a compressed state when
implanted. The frequency shall be between 1 Hz and 10 Hz.
Higher frequencies can be used if it is verified that the loop follows the testing plate without lag at all times.
No loop tested shall break.
For IOLs designed to move axially under compression, additional testing shall be considered.
4.11 Surgical manipulation
The IOL manufacturer shall provide evidence that the loops of an IOL design are capable of withstanding
surgical manipulations without failure. An appropriate test method and specification shall be established by the
manufacturer to ensure that the device does not fail at typical deformations. A test method, useful for some
designs with loops, is given in Annex H.
4.12 Surface and bulk homogeneity
The IOL shall be essentially free from defects, i.e. deviations from surface and bulk homogeneity that are not
intended features of the design, including all kinds of surface defects such as scratches, digs, protrusions,
cracks, roughness, etc., as well as bulk defects such as inclusions, bubbles, striae, discoloration, etc. The lens
should be inspected at 10× under optimal lighting conditions; any questionable or critical areas should be
viewed at higher magnification.
5 Recovery of properties following simulated surgical manipulation
The testing in this clause applies only to IOLs of which the optic is intended to be folded or compressed during
implantation. Perform testing on 10 lenses of each of the dioptric powers with the smallest and largest cross-
sectional dimensions. In practice this will typically be 10 lenses with the lowest and 10 lenses with the highest
dioptric power. Follow the instructions supplied by the manufacturer, using recommended lubricants and
instrumentation. To determine the acceptable time during which the lens is allowed to be kept deformed prior
to implantation, maintain the deformed state for a period of time. This time shall not be shorter than 3 min.
Times in excess of 20 min need not be investigated. The time used shall be reported.
After release from the deformed state, allow the lens to relax at in situ conditions up to 24 h ± 2 h. The time
used shall be reported. Subsequently:
a) measure dioptric power and image quality (see ISO 11979-2);
b) measure overall diameter and sagitta (see 4.2);
c) inspect for surface and bulk homogeneity (see 4.12).
The results shall be reported and are acceptable if they remain within manufacturing specifications of the
product.
4 © ISO 2006 – All rights reserved

ISO 11979-3:2006(E)
Annex A
(normative)
Measurement of compression force
A.1 Principle
The force exerted by the loops is measured when the IOL is confined to a prescribed diameter with the
movement of the body being unrestricted.
A.2 Apparatus
A diagram of the apparatus is shown in Figures A.1 and A.2 and comprises the following.
A.2.1 Two anvils, with faces having a radius of 5,00 mm ± 0,02 mm or 5,50 mm ± 0,02 mm, as appropriate,
constructed from a low-friction material to minimize loop rotational constraint, and aligned relatively with each
other.
A.2.2 Device, capable of measuring force accurate to at least ± 0,1 mN.
A.3 Procedure
A.3.1 Carry out the testing with the IOL in the horizontal plane.
NOTE Testing in the vertical plane leads to asymmetrical distribution of force between the loops due to the mass of
the IOL.
A.3.2 Set the anvils to a distance approximately equal to the overall dimension of the IOL and place the IOL
between the anvils.
A.3.3 Locate the IOL in the uncompressed state so that the line of compression bisects the angle of contact
in the compressed state or, in the case of IOLs where there are multiple contacts, so that the line of
compression bisects the angle of contact of the extremes in the compressed state (see Figure A.
...