ISO/DIS 11979-1.2:2025(en)

ISO TC 172/SC 7/WG 7

Secretariat: DIN

Date: 2025-02-24

Ophthalmic implants — Intraocular lenses — Part 1: Vocabulary

© ISO 2025

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Contents

Foreword iv

1 Scope 1

2 Normative references 1

3 Terms and definitions 1

4 Abbreviated terms 10

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 document 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).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

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This document was prepared by Technical Committee ISO/TC 172 , Optics and photonics, Subcommittee SC 7, Ophthalmic optics and instruments.

This fifth edition cancels and replaces the fourth edition (ISO 11979-1:2018), which has been technically revised.

The main changes are as follows:

— definitions of non-accommodative posterior chamber “Simultaneous Vision Range” (SVIOL) lenses that include the subtypes of MIOL (Multifocal), EDF (Extended Depth of Focus) and FVR (Full Visual Range) IOLs.

— definitions of properties related to SVIOLs

A list of all parts in the ISO 11979 series can be found on the ISO website.

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.

Ophthalmic implants — Intraocular lenses
Part 1:
Vocabulary

This document contains definitions of terms related to intraocular lenses and phakic intraocular lenses as well as definitions related to the methods used to evaluate these IOLs.

NOTE Terms are listed in the alphabetical order of the English terms in the English version of this document.

There are no normative references in this document.

For the purposes of this document, the following terms and definitions apply.

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

— ISO Online browsing platform: available at https://www.iso.org/obp

— IEC Electropedia: available at https://www.electropedia.org/

3.1

accelerated shelf-life study

stability study designed to increase the rate of chemical or physical degradation of a product by using exaggerated storage condition by temperature to establish an initial expiration dating period to be validated by real time study using the same methods of evaluation

3.2

accommodating intraocular lens

AIOL

IOL having continuous focusing from far point to near point by changing the dioptric power of the eye

3.3

accommodative amplitude

difference in refractive power between the near point and the far point of the eye

3.4

addition power

difference between the far power and the near power(s)

3.5

additional wrapping

protective packaging used in addition to the primary packaging which could be used to maintain sterility of the intraocular lens

3.6

anterior chamber lens

IOL designed to be placed entirely in the anterior chamber of the eye

3.7

aspheric intraocular lens

IOL having at least one optical surface which differs from a segment of a spherical optical surface

3.8

axial displacement in compression

taking the uncompressed state as reference, displacement of optic along the optical axis when the IOL is compressed to a specified diameter

3.9

axis mark

indicator of the meridian of lowest dioptric power of a toric IOL

Note 1 to entry: See Figure 1.

3.10

back focal length

BFL

distance from the back vertex of the IOL to the focal point with collimated light incident on-axis upon the IOL

3.11

base power

dioptric power that is intended to provide an in-focus image of an object at far (infinity)

Note 1 to entry: base power is same as far power

3.12

best-case subject

subject with no pre-operative ocular pathology detected at any time, no macular degeneration detected at any time, and no previous surgery for the correction of refractive errors

3.13

body

central part of an intraocular lens incorporating the optic

Note 1 to entry: See Figure 1.

3.14

clear optic

diameter of circle concentric with the optical axis of an intraocular lens, containing only features of the intraocular lens belonging to the optical design.

Note 1 to entry: Axis marks and positioning holes cannot be in the clear optic

Note 2 to entry: See Figure 1.

3.15

closed-loop intraocular lens

IOL model which contains two loops, each loop having both ends attached to the body of the optic

3.16

compression force

force exerted by the haptics of the IOL when compressed to a specified diameter

Key

Figure 1 — Overall diameter, vault height, sagittal distance, clear optic, body, positioning hole and axis mark

3.17

compression force after decay

residual compression force when the IOL has been confined to a specified diameter under in situ conditions for a specified time

3.18

compression force decay

process by which the compression force of an IOL is reduced over time when the IOL is held in a compressed state

3.19

cumulative adverse events

total number of adverse events that have occurred at any time up to a specified post operative time point

3.20

custom-made device

device specifically made in accordance with a duly qualified medical practitioner's written prescription, which gives, under his responsibility, specific design characteristics and it is intended for the sole use of a particular patient

Note 1 to entry: Mass-produced devices, which need to be adapted to meet the specific requirements of the medical practitioner, are not considered to be custom-made devices.

3.21

cut-off wavelength

wavelength at which spectral transmission drops below defined level

3.22

cylindrical power

difference in dioptric power between the meridians with the highest and the lowest dioptric powers

3.23

delivery system

instrument(s) or system used to implant the IOL into the eye

3.24

device history record

collection of records and reports assembled in a batch package, containing, or referring to, the relevant information pertaining to the manufacture and control of that batch of devices

3.25

dioptric power

reciprocal of the reduced paraxial focal length in situ for light, where paraxial focal length is the distance between the back principal plane and the back paraxial focal point, and reduced paraxial focal length is the paraxial focal length divided by the refractive index of the surrounding medium

Note 1 to entry: The unit for expressing dioptric power is the reciprocal metre (m-1). The special name for this unit is “dioptre”, for which the symbol “D” is used.

Note 2 to entry: Refer to ISO 11979-2 for the test conditions.

3.26

dynamic fatigue

fatigue durability by compressing the IOL to a specified dimension and giving cyclic compressive loading to the haptic

3.27

effective focal length

EFL

distance from the back principal plane to the focal point with collimated light incident on-axis upon the IOL

3.28

expiration date

termination of shelf-life, after which the intraocular lens is not to be used

3.29

extended depth of focus intraocular lens

EDF IOL

IOL having useful visual performance for far and intermediate distances

3.30

far point

farthest distance at which one can focus on an object

3.31

far power

far power is same as base power and use to differentiate from addition power(s)

3.32

far power configuration

configuration of an accommodating intraocular lens in the eye that is intended to result in a distant object being in focus in the retinal plane

3.33

finished intraocular lens lot

specific quantity of intraocular lenses that is intended to have uniform characteristics and quality, within specified limits, which is produced according to a single manufacturing order or during the same cycle of manufacture, and is packaged, labelled and sterilized

3.34

full visual range intoraocular lens

FVR IOL

IOL having useful visual performance for far, intermediate and near distances

3.35

haptic

non-optical, generally peripheral, component of an intraocular lens that is intended to keep the IOL in place and centrate it to the optical axis of the eye

3.36

hybrid open-loop/closed-loop intraocular lens

IOL model which contains two loops, with one loop having one end attached to the body of the IOL and the other end free, and the other loop having both ends attached to the body of the IOL

3.37

in situ

condition matching aqueous humour at 35 °C ± 2 °C

3.38

injector system

delivery system in which the IOL is compressed and/or folded and implanted through an incision

3.39

intraocular lens

IOL

ophthalmic lens intended for implantation inside the eye

3.40

intraocular lens model

series of IOLs which are identical in all design specifications except base power and cylindrical power related features such as optic central thickness

3.41

loop

type of haptic, either a peripheral extension of the body or a filament attached to the body at one or more points serving to position the intraocular lens in the eye

3.42

lost to follow-up subject

subject that has missed the post-operative case report form and for which there is no information available

3.43

manufacturer

natural or legal person with responsibility for the design, manufacture, packaging and labelling of a device before it is placed on the market under his own name, regardless of whether these operations are carried out by that person or on their behalf by a third party

Note 1 to entry: The obligations to be met by manufacturers also apply to the natural or legal person who assembles, packages, processes, fully refurbishes and/or labels a product.

3.44

manufacturing date

date when the medical device is manufactured, as defined by the manufacturer and which can be tracked from device history record (e.g., the date of starting manufacturing, the date of final packing, the date of sterilization, etc.)

3.45

meridian of highest dioptric power

meridian with the most positive or least negative dioptric power which is orthogonal to meridian of lowest dioptric power

3.46

meridian of lowest dioptric power

meridian with the least positive or most negative dioptric power which is orthogonal to meridian of highest dioptric power

3.47

monofocal intraocular lens

IOL having only the base power

3.48

multifocal intraocular lens

MIOL

IOL having a base power and at least on addition power providing near vision superior to monofocal intraocular lens

3.49

multi-piece intraocular lens

IOL assembled from separate haptics and body components

3.50

Nd-YAG laser exposure test

test that determines the physical and chemical effects of Nd-YAG laser exposure on a test material

3.51

near point

nearest distance at which one can focus on an object

3.52

near power

power that is intended to provide an in-focus image of an object at near or intermediate

3.53

non-ocular implantation test

test that evaluates the reciprocal tolerance of a test material and local tissue after implantation of the test material in a non-ocular site in an animal

3.54

null lens

lens used to neutralize toric lens cylindrical power or any other aberration combination

3.55

objective refraction

combination of sphere and cylinder powers that corrects the refractive errors of a subject´s eye determined by using techniques and instruments, without relying on the subject's responses or feedback, and/or process of its determination

3.56

ocular implantation test

test that evaluates biocompatibility of a test material after implantation in the eye of an appropriate animal

3.57

one-piece intraocular lens

IOL where the haptics are same material as the body, or the haptics are integrally bonded with the body

3.58

open-loop intraocular lens

IOL model which contains two loops, each loop having one end attached to the body of the IOL and the other end free

3.59

optic

image-forming, generally central, component of an intraocular lens

3.60

optic decentration

displacement between the centre of optic body and the centre of well when compressed to a specified diameter in the well

3.61

optic shape factor

factor associated with the curvatures of the refracting surfaces of the optic (e.g. plano-convex, bi-convex)

where

3.62

optic tilt

angle between the optical axis in the uncompressed state and that in the compressed state, with the intra-ocular lens being confined to a prescribed diameter

3.63

optical power of the eye

reciprocal of the reduced focal length of an eye

3.64

overall diameter

diameter of the circumscribing circle of an intraocular lens

Note 1 to entry: The axis of cylinder being parallel with the optical axis of the intraocular lens

Note 2 to entry: See Figure 1.

3.65

package system

combination of a sterile barrier system and protective packaging

3.66

paraxial focal length

distance between the back principal plane and the back paraxial focal point

3.67

parent intraocular lens model

intraocular lens model that a manufacturer has qualified based on a clinical investigation and that meets the requirements of all applicable parts of ISO 11979

3.68

patient information leaflets

PIL

patient information material providing information that can be used to inform discussions on the decision to implant a type of medical device

3.69

patient implant card

PIC

patient information material used to record the details of the specific device that the patient has implanted to enable improved traceability of the device if there are an issue or recalls

3.70

persistent adverse event

adverse event that is present at the end of a clinical investigation

3.71

phakic intraocular lens

PIOL

IOL having indication for which is the modification of the refractive power of a phakic eye

3.72

phakic multifocal intraocular lens

PMIOL

PIOL having useful visual performance at least two distances, far and near distances

3.73

phakic toric intraocular lens

PTIOL

PIOL having different powers in orthogonal meridians

3.74

plate haptic intraocular lens

IOL made from flexible material that are one piece plate design

3.75

positioning hole

hole, whether penetrating or not, intended to be used for surgical manipulation

Note 1 to entry: See Figure 1.

3.76

posterior chamber lens

posterior chamber intraocular lens

IOL designed to be placed entirely in the posterior chamber of the eye

3.77

pre-loaded delivery system

primary package to act as delivery system or part thereof in which the IOL is pre-packaged and sterilized

3.78

primary package

packaging that comes into direct contact with the IOL

3.79

protective packaging

configuration of materials designed to prevent damage to the sterile barrier system and its contents from the time of their assembly until the point of use

3.80

reduced focal length

focal length divided by the refractive index of the medium in image space

3.81

sagittal distance

maximum distance between the planes, normal to the optical axis, which contact, respectively, the most anterior and the most posterior points, be it haptic or optic, of an uncompressed IOL

Note 1 to entry: See Figure 1.

3.82

seal closure integrity

packaging characteristics of a closure to minimize the risk of ingress of microorganisms

3.83

self-adhesive label

label included in the protective packaging with specific information of IOL

3.84

shelf-life

period during which an IOL remains suitable for implantation in the human eye

3.85

simulated visual acuity

predicted visual acuity computed using measured modulation transfer function value(s) or other objective optical performance metrics/objective optical tests

3.86

simultaneous vision intraocular lens

SVIOL

non-accommodative IOL having simultaneous vision at multiple distances

Note 1 to entry: Simultaneous vision IOL include multifocal, full visual range, and extended depth of focus lenses.

3.87

spherical equivalent power

mean of the dioptric powers in the meridians with the highest and lowest dioptric powers

3.88

spherical intraocular lens

IOL in which both optical surfaces consist of a segment from a sphere with same dioptric power on all meridians, one of the surfaces may also be flat

3.89

stability

extent to which a product retains properties and characteristics within the manufacturer's specified limits, throughout its period of storage, i.e. its shelf-life

3.90

sterile barrier system

property of a sterile barrier system to minimize the risk of ingress of microorganisms

3.91

sterilization load

products to be, or that have been, sterilized together using a given sterilization process

3.92

subjective refraction

combination of sphere and cylinder correction that optimizes a subject´s visual acuity utilizing the subject’s response, and/or process of its determination

3.93

surgical manipulations

manipulations of the IOL that take place during the surgical implantation procedure that the IOL, especially the haptics, must withstand without failure

3.94

test material

sterile finished IOL as intended for human implantation, or representative sample material manufactured and processed using a procedure equivalent to that used for the IOL

Note 1 to entry: If using IOL as test material, it is preferable to choose lenses with powers within ±2 D of the mean of the power range, e.g. in general 18 D to 22 D.

3.95

test of photostability

test that determines the potential for degradation of a test material due to exposure to light

3.96

toric intraocular lens

TIOL

IOL having different powers in orthogonal meridians

3.97

vault height

distance from a plane normal to the optical axis, containing the point most proximal to the iris of the uncompressed haptic of an IOL, to the plane normal to the optical axis, containing the vertex of the iris proximal optical surface

Note 1 to entry: See Figure 1.

Note 2 to entry: The iris proximal side of the IOL refers to the intended position as implanted.

Note 3 to entry: The vault height is positive if the distance defined is in the direction towards the retina as implanted, and negative if not.

3.98

vertex

point of intersection of the optical axis with the surface of a lens

3.99

visual acuity

number characterizing the ability of the visual system to recognize optotypes

The following abbreviations are used: