SIST EN ISO 11980:2025

SLOVENSKI STANDARD
01-september-2025
Nadomešča:
SIST EN ISO 11980:2013
Očesna optika - Kontaktne leče in izdelki za vzdrževanje kontaktnih leč - Zahteve
in navodilo za klinične raziskave (ISO 11980:2025)
Ophthalmic optics - Contact lenses and contact lens care products - Requirements and
guidance for clinical investigations (ISO 11980:2025)
Augenoptik - Kontaktlinsen und Kontaktlinsenpflegemittel - Leitfaden für die klinische
Prüfung (ISO 11980:2025)
Optique ophtalmique - Lentilles de contact et produits d'entretien pour lentilles de contact
- Directives pour les investigations cliniques (ISO 11980:2025)
Ta slovenski standard je istoveten z: EN ISO 11980:2025
ICS:
11.040.70 Oftalmološka oprema Ophthalmic equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 11980
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2025
EUROPÄISCHE NORM
ICS 11.040.70 Supersedes EN ISO 11980:2012
English Version
Ophthalmic optics - Contact lenses and contact lens care
products - Requirements and guidance for clinical
investigations (ISO 11980:2025)
Optique ophtalmique - Lentilles de contact et produits Augenoptik - Kontaktlinsen und
d'entretien pour lentilles de contact - Exigences et Kontaktlinsenpflegemittel - Leitfaden für die klinische
recommandations pour les investigations cliniques Prüfung (ISO 11980:2025)
(ISO 11980:2025)
This European Standard was approved by CEN on 24 June 2025.

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 CEN-CENELEC Management Centre 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 CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11980:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 11980:2025) has been prepared by Technical Committee ISO/TC 172 "Optics
and photonics" 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 January 2026, and conflicting national standards shall
be withdrawn at the latest by January 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 11980:2012.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 11980:2025 has been approved by CEN as EN ISO 11980:2025 without any modification.

International
Standard
ISO 11980
Fourth edition
Ophthalmic optics — Contact lenses
2025-06
and contact lens care products —
Requirements and guidance for
clinical investigations
Optique ophtalmique — Lentilles de contact et produits
d’entretien pour lentilles de contact — Exigences et
recommandations pour les investigations cliniques
Reference number
ISO 11980:2025(en) © ISO 2025
ISO 11980:2025(en)
© ISO 2025
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 below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 11980:2025(en)
Contents Page
Foreword .iv
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Clinical investigational requirements . 1
4.1 General .1
4.2 Additional requirements .2
4.2.1 Study design .2
4.2.2 Contact lens and contact lens care product variables .4
4.3 Other considerations .5
Annex A (informative) Elements of a clinical investigation (CI) . 6
Annex B (informative) Grading scales for the evaluation of safety, physiological performance
and effect on ocular tissues . 19
Annex C (informative) The evaluation of visual, refractive and lens performance and subjective
performance .25
Bibliography .29

iii
ISO 11980:2025(en)
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.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of 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 www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 172,Optics and photonics, Subcommittee
SC 7, Ophthalmic optics and instruments, in collaboration with the European Committee for Standardization
(CEN) Technical Committee CEN/TC 170, Ophthalmic optics,in accordance with the Agreement on technical
cooperation between ISO and CEN (Vienna Agreement).
This fourth edition cancels and replaces the third edition (ISO 11980:2012), which has been technically
revised.
The main changes are as follows:
— the title was changed to reflect the requirements;
— the Scope was clarified;
— the inclusion and exclusion criteria (4.2.1.1) were clarified;
— the appropriate controls in 4.2.1.2, 4.2.1.3 and A.2.2 were clarified;
— the clinical assessment variables (4.2.2.2 and 4.2.2.3) were updated and clarified;
— the guidance for minimum completed participants were updated and the material and design details
(Table A.1) were clarified;
— the contact lens group information for contact lens care product testing (A.2.2.2) was updated;
— the statistical considerations (A.2.3) were clarified;
— the details of serious adverse events (A.2.4.2) were clarified;
— examples of significant adverse events (A.2.4.3) were added;
— to clarify suggested reporting of results, Tables A.2 to A.15 were updated;
— a bulbar conjunctival staining grading scale (B.7) was added;

iv
ISO 11980:2025(en)
— to clarify quadrants of interest, Figure B.2 was updated;
— grading scales for anterior chamber cells and flare (B.9) were added;
— the visual performance testing (C.2) was clarified;
— the refractive performance (C.3) was clarified;
— the front surface deposits grading scale (C.6.2) was revised;
— the Bibliography was updated.
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.

v
ISO 11980:2025(en)
Introduction
Currently, contact lenses and contact lens care products are regulated in different ways in different
countries. This document has been developed to encourage global alignment. Widespread adoption of this
document can represent yet another step toward universal recognition. This document can also be used as a
basis to fulfil design elements of ISO 9001 and or ISO 13485 as well as related national laws.

vi
International Standard ISO 11980:2025(en)
Ophthalmic optics — Contact lenses and contact lens
care products — Requirements and guidance for clinical
investigations
1 Scope
This document gives requirements and guidelines for the clinical investigation (CI) to establish the safety
and performance of contact lenses and contact lens care products.
NOTE 1 This document attempts to align the recognised regulatory requirements for the conduct of a CI to meet the
marketing and labelling requirements for contact lenses and contact lens care products around the world. However,
national requirements vary greatly. Wherever national practice or regulations dictate some legal requirement, this
requirement takes precedence over this document.
NOTE 2 For indications beyond correction of refractive error, additional considerations for safety and performance
are to be included in the clinical investigation plan (CIP).
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.
ISO 14155, Clinical investigation of medical devices for human subjects — Good clinical practice
ISO 14534, Ophthalmic optics — Contact lenses and contact lens care products — Fundamental requirements
ISO 18369-1, Ophthalmic optics — Contact lenses — Part 1: Vocabulary, classification system and
recommendations for labelling specifications
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14155, ISO 14534 and
ISO 18369-1 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/
4 Clinical investigational requirements
4.1 General
The general requirements for a CI and for a CIP given in ISO 14155 shall apply, with additional requirements
given below.
ISO 11980:2025(en)
4.2 Additional requirements
4.2.1 Study design
4.2.1.1 General
a) The inclusion criteria for participant selection shall relate to the study objectives and should include,
but not be limited to:
1) participants with eyes appropriate for the study being conducted;
2) participants of appropriate age for the study being conducted (age range to be specified);
3) participants requiring lens powers within the range available for the study lenses;
4) the manifest cylinder less than or equal to 1,00 D (for a study with only spherical power correcting
soft lenses. For rigid contact lenses, the suitable manifest cylinder can be higher and shall be
specified in the inclusion criteria);
5) best spectacle corrected visual acuity greater than or equal to 20/25 (less than or equal to
LogMAR 0,1).
b) The exclusion criteria for participant selection shall relate to the study objectives and should include,
but not be limited to
1) anterior segment infection, inflammation or abnormality,
2) any active anterior segment ocular disease that would contraindicate contact lens wear,
3) the use of systemic or ocular medications that would contraindicate contact lens wear,
4) history of herpetic keratitis,
5) history of refractive surgery or irregular cornea (except when the contact lens or contact lens care
product under investigation is indicated for ocular conditions such as irregular cornea, keratoconus
or refractive surgery),
6) slit lamp findings that are more serious than grade 1 (see Annex B containing grading scales),
7) inactive (i.e. ghost) vessels greater than 1 mm of penetration into the cornea, and
8) participation of the participant in a contact lens or contact lens care product clinical trial within
the previous 90 days (orthokeratology), 30 days (extended wear, rigid gas permeable corneal and
scleral lenses) or 15 days (daily disposable, daily wear).
c) The CIP shall provide a description of the monitoring procedure to ensure consistent quality of data
collection and recording based on the chosen intended purpose.
d) The CIP shall include a statistical analysis plan. Sample size shall be statistically justified.
4.2.1.2 Contact lenses
4.2.1.2.1 General
A CI of contact lenses, including daily wear and extended wear hydrogel, silicone hydrogel, and rigid gas-
permeable contact lenses, shall be designed as one of 4.2.1.2.2 or 4.2.1.2.3.
For CIPs to demonstrate safety and performance based on the chosen intended purpose, as well as special
claims (e.g. comfort), labelling or additional indications, the following is required per wearing modality
to be investigated: a pre-determined statistical analysis plan (including sample size calculations) shall be
specified in the clinical protocol. Where feasible, the CIP shall specify objective endpoints to help support
such claims.
ISO 11980:2025(en)
Bilateral studies are preferred to contralateral studies, due to the potential dependence between the two
eyes and concerns regarding participant compliance.
NOTE Annex A provides guidance for the design of a CI.
4.2.1.2.2 Prospective, concurrently controlled study
For investigations evaluating hydrogel, silicone hydrogel or rigid gas-permeable contact lenses, a prospective,
concurrent control study design shall be followed. Either a
a) bilateral crossover design, or
b) parallel groups (inter-participant controls) design, or
c) contra-lateral eye (i.e. intra-participant controlled) design shall be utilised.
If parallel groups/inter-participant controls are utilised, the ratio of test participants to control participants
can be either 2:1 or 1:1.
The control lens shall be a currently cleared, registered, or approved contact lens in use for the same modality,
in all countries where the study is performed. Randomisation and masking (participant, investigator, and
evaluator) shall be employed where possible to minimise the potential for bias. Participants shall be divided
evenly between study investigators.
A single arm study is acceptable for orthokeratology studies (overnight or daily wear).
4.2.1.2.3 Uncontrolled study
Here, results are compared to a historical control. Alternative investigational study designs, such as historical
controls, shall be utilised when a sponsor has a clinical database on a cleared, registered, or approved
contact lens to use as a comparator. If any historical control is used, the control group shall be defined and
adequately characterised for comparison to the test group. Compatibility of test and control groups shall be
demonstrated by comparison of the selection criteria, demographics, refractive characteristics, contact lens
wearing history and in the CIPs used.
4.2.1.3 Contact lens care products
For investigations evaluating contact lens care products, a prospective concurrent control study design
shall be followed. It is recommended that the ratio of test to control participants be either 2:1 or 1:1. The
control care product shall be a currently cleared, registered, or approved contact lens care product in
all countries where the study is performed. Randomisation and masking (participant, investigator, and
evaluator) shall be employed where possible to minimise the potential for bias. Participants shall be divided
evenly between study investigators. Alternative investigational study designs, such as use of historical
controls, can be utilised when a sponsor has a clinical database on a cleared, registered, or approved care
product to use for comparison. If any historical control is used, the control group should be defined and
adequately characterised for comparison to the test group. Compatibility of test and control groups should
be demonstrated by comparison of the selection criteria and CIPs used.
For CIPs to demonstrate safety and performance, as well as special claims (e.g. comfort), labelling or
additional indications, the following is required for the care products: a pre-determined statistical analysis
plan (including sample size calculations) shall be specified in the clinical protocol. Where feasible, the
protocol should specify objective endpoints to help support such claims.
Bilateral studies are preferred to contralateral studies, due to the potential dependence between the two
eyes and concerns regarding participant compliance.
In a contact lens care product investigation, a daily wear schedule shall be followed for most products in
order to maximise the participant's exposure to those products. However, a study of a lens or a periodic
cleaner, used at weekly intervals, can provide more valuable clinical data concerning effectiveness when
extended wear participants are enrolled than a similar investigation with daily wear participants.

ISO 11980:2025(en)
When a daily wear schedule is used and safety is a primary objective, one post-dispensing visit should be
done 1 h to 2 h after lens insertion in order to permit observation of corneal and conjunctival staining, and
redness caused by an immediate toxicity reaction.
A contact lens care product with a cleaning indication shall have an objective measure of lens deposits on at
least one lens collected from each participant at the end of the clinical study.
If the sponsor of a contact lens care product wishes to recommend its use with a specific type of lens in the
labelling, the compatibility with the lens type should be confirmed pre-clinically and during the clinical trial.
If the CI has not collected any data on use with a particular type of lens material (such as silicone hydrogel
lenses), the product label should clearly state this fact.
NOTE 1 Annex A provides guidance for the design of a CI.
4.2.2 Contact lens and contact lens care product variables
4.2.2.1 General
The following variables listed in 4.2.2.1 and 4.2.2.2 should be assessed during the CI for contact lenses and
lens care products.
4.2.2.2 Contact lens assessments
a) visual acuity;
b) refractive performance (refractive changes from baseline to final visit as specified in C.3);
c) anterior corneal curvature measurements e.g. keratometry, corneal topography;
d) lens position/centration;
e) lens movement;
f) lens surface wettability;
g) lens surface deposits;
h) lens condition e.g. defects, damage, discolouration
i) participant rating of comfort;
j) participant rating of vision;
k) participant rating of handling.
Additional variables can be studied in the CI to support specific claims.
NOTE 1 Annex C provides guidance on grading of each of these variables.
NOTE 2 Participant rating of symptoms, problems or complaints can also be collected.
4.2.2.3 Anterior segment assessments
a) corneal oedema;
b) corneal infiltrative events;
c) corneal vascularisation;
d) corneal staining;
e) conjunctival observations;
ISO 11980:2025(en)
f) palpebral conjunctival observations;
g) corneal ulcers;
h) corneal opacification;
i) hypopyon;
j) anterior uveitis;
k) corneal scarring.
Additional variables can be studied in the CI to support specific claims.
NOTE 1 Corneal thickness, endothelial irregularity and endothelial cell density can also be measured in extended
wear or overnight orthokeratology studies.
NOTE 2 Annex B provides guidance on classifications for some of these variables.
4.3 Other considerations
Serious ophthalmic adverse events and all adverse device effects shall be reported using an adverse event
case report form and forwarded to the sponsor and related authorities as required. All other ophthalmic
adverse events shall be reported using the standard visit case report forms.

ISO 11980:2025(en)
Annex A
(informative)
Elements of a clinical investigation (CI)
A.1 General
The following are elements of a CIP which can assist in collecting data for the purpose of determining the
safety and performance of contact lenses and contact lens care products.
To minimise risks in extended wear and overnight orthokeratology modalities, assessments of variables
such as corneal thickness/oedema are recommended prior to conducting the CI to determine safety and
performance.
A.2 Study size and duration
A.2.1 Contact lens investigations
Guidance to participant numbers suggested for contact lens clinical investigations of correction of refractive
error is given in Table A.1.
Table A.1 — Guidance to the participant numbers (minimum completed participants) suggested for
contact lens clinical investigations of correction of refractive error (informative)
Minimum partici-
Wearing schedule
pant number com-
or replacement fre- Duration Material and design
pleted per group at
quency
end of trial
a
Daily wear Containing new material components ; signif-
50 3 months
b
icant design changes
—  reusable
—  disposable (single
c
30 30 days Containing new ratio of material components
use)
3 months or longer
a
Daily wear orthoker- if necessary to reach Containing new material components ; signif-
b
atology stability as defined in icant design changes
the CIP
a
Extended wear, Containing new material components ; signif-
160 12 months
b
up to 7 days icant design changes
a
Extended wear, Containing new material components ; signif-
570 12 months
b
up to 30 days icant design changes
Registered, or approved established material
160 12 months for extended wear; significant design chang-
Overnight orthokera-
b
es
tology
300 12 months Containing new material components
a
Containing new material components not previously registered or approved
b
Significant design changes are ones that introduce new or additional risks.
c
With different physicochemical properties (water content and oxygen permeability (Dk) not within ISO tolerance as specified
in ISO 18369-2:2017, Table 4).
NOTE 1 Actual sample sizes used in a study are to be based upon statistical calculations concerning all relevant
issues to evaluate safety and performance.
NOTE 2 A single arm study can be used for orthokeratology studies (overnight or daily wear).

ISO 11980:2025(en)
A.2.2 Contact lens care product investigations
A.2.2.1 Contact lens care products, including saline solutions, daily cleaners, periodic cleaners, disinfecting
solutions, neutralisers, “in-eye” solutions, conditioning solutions, and multipurpose solutions that have
any new active ingredient, or any active ingredient outside the concentration range used in a comparable
cleared, registered, or approved product, should undergo a 3-month clinical study.
A.2.2.2 Products for use with soft (hydrophilic) lenses: sample size (completed) should be 30 participants
in the test solution and 15 participants in the control solution (a currently cleared, registered, or approved
solution for the same indication) for each appropriate representative category such as:
— Group 1;
— Group 4;
— A separate group for each silicone hydrogel lens Group 5, A, B and, C with and without surface modifications
as described in ISO 18369-1:2017, 4.6, Table 3 and 4.9. For example, for 6 contact lens groups/subgroups;
with 30 participants in the test and 15 in the control, a minimum of 270 total completed participants
should be evaluated at the end of the study.
A.2.2.3 Products for use with rigid lenses: sample size (completed) should be 30 participants using the
test solution and 15 participants using the control solution (a currently cleared, registered, or approved
solution for the same indication) for each appropriate material group.
A.2.2.4 For a contact lens solution that does not contain any new active ingredients (as described in
A.2.2.1), but contains any active ingredient lower than the concentration range used in a comparable cleared,
registered, or approved product, a 1-month clinical study should be conducted. In this case, the sample size
should be about half of that recommended in A.2.2.2 and A.2.2.3, using the same general distribution of
participants.
A.2.3 Statistical considerations for contact lens and lens care product safety evaluations
A.2.3.1 General
Primary safety analysis: the key safety endpoint should be the frequency of serious and significant adverse
events calculated by participant and not by eye, except for contralateral studies.
A.2.3.2 Extended wear evaluations
The null hypothesis, H , is that the test rate of endpoint adverse events, p , minus the control rate of endpoint
0 t
adverse events, p , is greater than or equal to the clinically insignificant difference, δ, between the two rates,
c
as given by Formula (A.1):
H : p − p ≥ δ (A.1)
0 t c
The alternative hypothesis, H , is that the test rate of endpoint adverse events, p , minus the control rate
a t
of endpoint adverse events, p , is less than a clinically insignificant difference, δ, between the two rates, as
c
given in Formula (A.2):
H : p − p < δ (A.2)
a t c
where
p is the proportion in the test population;
t
p is the proportion in the control population.
c
ISO 11980:2025(en)
When using a 1:1 ratio of patient allocation between treatment and control, the minimum number, n, of
completed patients necessary for each treatment group is determined by Formula (A.3):
()ZZ+×[(pp11−+)(pp− )]
11−−βα tt cc
n= (A.3)
δ
where
α is the significance level (also known as the type 1 error rate);
1 − β is the power of the test;
Z is the standard normal quantile.
The following is an example of the calculation that makes assumptions found to be reasonable for clinical
studies of 7 day extended wear hydrogel or silicone hydrogel contact lenses. With a control rate, p , and a
c
test rate, p , of 0,033 (under H ), a clinically insignificant difference, δ, of 0,05, a power, 1 − β, of 0,80, and a
t a
significance level, α, of 0,05, the minimum number of completed patients per treatment group is given by
Formula (A.4):
(,0841+×,)64 [,0 033×−(,10 033),+×0 033 (,10− 033)]
n= ≈158 (A.4)
00, 5
This formula is only valid when it is assumed for the alternative hypothesis, H , that the test rate of adverse
a
events is equal to the control rate, p = p . When this is not a valid assumption, the following Formula (A.5)
t c
can be used to provide an approximate calculation for the sample size:
()ZZ+×[(pp11−+)(pp− )]
11−−βα tt cc
n= (A.5)
()pp−−δ
tc
For clinical studies of 30 day extended wear hydrogel contact lenses, it is recommended that a 7 day
extended wear lens (worn for up to 6 nights/7 days) be used as the control. The following is an example of
the calculation that makes assumptions found to be reasonable for many clinical studies of 30 day extended
wear hydrogel contact lenses. With a control rate, p , of 0,033 and a test rate, p , of 0,053 (under H ), a
c t a
clinically insignificant difference, δ, of 0,05, a power, 1 − β, of 0,80, and a significance level, α, of 0,05, the
minimum number of completed participants per treatment group is given by Formula (A.6):
(,0841+×,)64 [,0 053×−(,10 053),+×0 033 (,10− 033)]
n= ≈562 (A.6)
(,0 053−00, 333−00,)5
Enrolment should be adjusted to compensate for drop-out which is typically 20 % to 25 % in 1 year contact
lens studies. Therefore, for the above example of a clinical study of a 7-day extended wear contact lens, the
recommended sample size would be adjusted to approximately 215 per participant group. For the above
example of a study of a 30-day extended wear lens, the recommended sample size would be approximately
760 per participant group.
At the conclusion of the study, sensitivity analyses (e.g. multiple imputation analyses) should be conducted
to evaluate the robustness of the study result accounting for missing observations, if there is more than
minimal participant drop-out.
The full safety analysis should provide a complete discussion and evaluation of the rates of each type of
adverse events, the seriousness, severity, duration, necessary treatment, and sequelae for each reported
adverse event, a brief case history for each adverse event, and an overall evaluation of relative safety results
of the two arms based upon all these factors.

ISO 11980:2025(en)
A.2.3.3 Daily wear hydrogel, silicone hydrogel or rigid gas-permeable contact lens evaluations
Sample sizes are designed to give reasonable assurance of obtaining at least one complication, as a function
of the expected complication rate, with a probability of greater than 95 %. For example,
— with 30 participants, we have 95 % confidence to detect at least one adverse event, assuming 10 %
hypothetical complication rate, and
— with 50 participants, we have 95 % confidence to detect at least one adverse event, assuming
6 % hypothetical complication rate.
Therefore, in a participant group of 30 (completed) participants exposed to a short-term duration (30 days)
of a test product, an adverse event occurrence in two to three participants can cause concern as to the
biocompatibility and fundamental safety of the device being tested.
Any investigation resulting in more than one adverse reaction should include adequate justification in order
to establish safety and efficacy.
Expected complication rates should be based on previous studies and/or peer-reviewed literature.
A.2.3.4 Contact lens care product evaluations
Clinical sample sizes are designed so that there is 95 % confidence that a study has at least one complication
in a material category. In a hypothetical example, if the true complication rate is ≥10 %, this implies that a
study should have at least 30 (completed) participants exposed to a short-term duration (30 days) of a test
care product, for each material grouping. Studies should include all material groupings of interest for the
product.
Any investigation resulting in more than one adverse reaction should include adequate justification in order
to establish safety and efficacy.
Expected complication rates should be based on previous studies and/or peer-reviewed literature.
A.2.4 Adverse events and adverse device effects
A.2.4.1 General
Adverse events should be differentiated into device related and non-device related. Any corneal infiltrate,
ulcer, vascularisation, etc. shall be presumed to be device related unless the case history clearly indicates
some other origin. Any serious adverse events that can impact visual acuity shall be recorded in the study
report, including presumed diagnosis/aetiology. All participants experiencing an adverse event should be
followed until the adverse event has resolved or stabilised.
All adverse events and any new information concerning these events shall be documented in a timely
manner throughout the CI and shall be reported as specified in ISO 14155:—, 9.2.5 and 10.8. For adverse
event categorisation, also see ISO 14155:—, Annex F.
A.2.4.2 Serious adverse events
Serious adverse events are those events that result in, or have potential to cause, either permanent
impairment of an ocular function or damage to an ocular structure or can necessitate medical or surgical
intervention.
Serious adverse events can include any hazardous, sight-threatening conditions occurring after exposure to
test article, including but not limited to the following:
a) A presumed infectious ulcer (defined as a progressive erosion of the corneal tissue). Signs can include
irregular focal infiltrates (>1 mm); active lesions with raised edges; significant diffuse infiltration;
anterior corneal to mid-stromal involvement; erosion with overlying staining; conjunctival and lid
oedema; anterior chamber reaction (anterior uveitis); bulbar and limbal redness. Symptoms associated
with a presumed infectious ulcer (microbial keratitis) can include pain of rapid onset; redness; purulent

ISO 11980:2025(en)
or muco-purulent discharge; tearing; photophobia. For the purposes of reporting, a corneal ulcer which
has any of the following characteristics should be considered in this category:
1) central 6 mm location;
2) penetration of Bowman's membrane;
3) infiltrate >2 mm diameter;
4) associated with anterior uveitis ≥grade 2 (see B.9 for grading scale);
5) associated with any increase in intraocular pressure;
6) culture positive for microorganisms;
7) increasing size or severity at subsequent visits.
b) Any central 6 mm corneal event (such as vascularisation) that results in permanent opacification.
c) Any serious adverse ophthalmic events including hypopyon.
d) Any corneal vascularisation within the central 6 mm of the cornea.
e) The loss of two or more lines of visual acuity that fail to resolve after resolution or stabilisation of signs
and symptoms.
f) All cases of anterior uveitis.
A.2.4.3 Significant adverse events
The following are examples of significant adverse events (which can be symptomatic or asymptomatic).
Significant adverse events are those that
— warrant discontinuation (temporary or permanent) of the test article, or
— require intervention due to the disruption of normal ocular structure or function (including reported
significant patient symptoms), or
— the clinical investigator regards as significant.
Significant but non-serious adverse events should include, but not be limited to
— peripheral non-progressive presumed non-infectious ulcers,
— all symptomatic presumed non-infectious corneal infiltrative events,
— all cases of corneal staining greater than or equal to grade 3,
— any temporary loss of two or more lines of best corrected visual acuity,
— all cases of corneal vascularisation greater than or equal to grade 2, and
— any ocular event that necessitates temporary lens discontinuation.
A.3 Reporting of results
Tables A.2 to A.15 give guidance for sample tables of results. Separate tables can be used for test and control
groups. Not all tables apply to studies for all product categories.

ISO 11980:2025(en)
Table A.2 — Accountability by eyes enrolled in the study and distribution status
Number of eyes
Status
Control eyes Trial eyes
N N
C T
Enrolled
Completed N N
C T
Active lens wearers (visit complet-

ed)
dispensed N N
C T
1st follow-up N N
C T
2nd follow-up N N
C T
(list through nth follow-up)
Discontinued N N
C T
Lost to follow-up (no-show) N N
C T
Enrolled not dispensed N N
C T
Total enrolled N N
C T
Table A.3 — Tabulation of eyes by most recent lens-wearing experience and demographics
Eyes
Total
Hydrogel Silicone hydro-
Rigid lens Other Subtotal
lens gel lens
Previous experience
unreported
No prior lens experi-
ence
New wearers
(less than 1 months'
wear)
Previous wearers:
most recent experi-
ence
Successful:
daily wear
extended wear
other
Unsuccessful:
daily wear
extended wear
other
Total lens wearers
Total enrolled
ISO 11980:2025(en)
Table A.4 — Demographics
Demographics
Age of participants: From to Average:
Sex: Female: Male: Ratio:
Ethnicity or Race
Geographic location
Lens power range: + D
(maxima)
− D
Cylinder D
Table A.5 — Adverse events
Non-device related
Diagno- Resolu- Final best
sis/ tion Sta- Inter- Outcome corrected
Time in Date
Descrip- tus (re- vention/ Partic- / Seque- distance
investiga- first
Adverse tion solved or Treatment ipant Sever- la (or VA (indi-
tion seen by
event ongoing) (therapeu- discon- ity resolved cate any
(from dis- investi-
/ Date of tic / moni- tinued? without loss of
pensing) gator
Resolu- toring) sequela) letters or
tion lines)
etc.
Total number of non-device-related adverse events:
Device related
Resolu- Final best
Inter-
tion Sta- Outcome corrected
Time in Date
vention/
Adverse Diagno- tus (re- Partic- / Seque- distance
investiga- first
Treatment
device sis/ solved or ipant Sever- la (or VA (indi-
tion seen by
event Descrip- ongoing) discon- ity resolved cate any
(therapeu-
(from dis- investi-
(ADE) tion / Date of tinued? without loss of
tic / moni-
pensing) gator
Resolu- sequela) letters or
toring)
tion lines)
etc.
Total eyes with adverse device events requiring treatment:

ISO 11980:2025(en)
Table A.6 — Slit lamp findings (example: epithelial oedema) by visit, tabulated by eyes and
incidence rate
Initial
Un-scheduled Final
dispensing Intermediate visits
visits visit
Epithelial
visit
oedema
1 2 3 4 1
No. % No. % No. % No. % No. % No. % No. %
0 = none
1 = trace
2 = mild
3 = moderate
4 = severe
Total eyes
Table A.7 — Symptoms, problems, and complaints (example: comfort) by visit, tabulated by eyes and
incidence rate
Initial Overall
Unsched-
dispensing Intermediate visits Final visit total
uled visits
Total eyes at
visit
visit
1 2 3 4
No. % No. % No. % No. % No. % No. % No. % No. %
a
Comfort
0 = excellent,
cannot be felt
1 = very com-
fortable
...