ISO 18259:2014

Ophthalmic optics - Contact lens care products - Method to assess contact lens care products with contact lenses in a lens case, challenged with bacterial and fungal organisms

ISO 18259:2014 specifies an antimicrobial efficacy end point methodology to determine compatibility of contact lens solutions, lens cases and hydrogel lenses for disinfection. This provides a process for evaluating compatibility of solutions used for disinfection with contact lenses and lens cases using an antimicrobial efficacy end point. Specifically, the microbiological effect of the antimicrobial agent(s) while in the presence of the lens cases and/or lenses will be evaluated as described in the soak step of the label instructions.

Optique ophtalmique — Produits d'entretien de lentilles de contact — Méthode d'évaluation des produits d'entretien des lentilles de contact avec les lentilles de contact dans leur étui, en présence de contamination par des bactéries et champignons

General Information

• Status: Published
• Publication Date: 22-Sep-2014
• ICS: 11.040.70 - Ophthalmic equipment
• Technical Committee: ISO/TC 172/SC 7 - Ophthalmic optics and instruments
• Drafting Committee: ISO/TC 172/SC 7/WG 9 - Contact lenses
• Current Stage: 9093 - International Standard confirmed
• Start Date: 22-Nov-2024
• Completion Date: 13-Dec-2025

Overview

ISO 18259:2014 - Ophthalmic optics - Contact lens care products - Method to assess contact lens care products with contact lenses in a lens case, challenged with bacterial and fungal organisms - specifies an antimicrobial efficacy end-point test to evaluate compatibility of contact lens solutions, lens cases and hydrogel lenses for disinfection. The method simulates real-world contamination introduced during patient handling by inoculating lenses in lens case wells with microbial challenge organisms (including the five ISO 14729 challenge organisms), adding product solution, and measuring microbial survival after labelled soak periods.

Key features:

• Tests the microbiological effect of preservative(s) in the presence of lenses and lens cases (soak step).
• Excludes oxidative disinfection systems for practical purposes.
• Produces log-reduction data to assess disinfection performance and compatibility.

Key topics and technical requirements

• Test principle: Inoculate lenses placed in lens case wells with bacterial and fungal organisms in organic soil, allow 3–10 minutes contact, then add the test solution and store for defined time points.
• Soak and sampling times: Minimum regimen soak (labelled), 24 h, 7 days, and maximum labelled storage; additional time points allowed.
• Lens & case selection: New, unused lenses (representative groups e.g., Group I, IV, V) and the manufacturer-recommended lens case(s) are evaluated.
• Challenge organisms & soil: Use the five challenge organisms specified in ISO 14729; organic soil prepared per Annex A (heat‑killed yeast + serum).
• Sample handling: Vortex each lens case before sampling, remove lens, withdraw aliquot, neutralize antimicrobial agents (validated neutralizing media or membrane filtration), perform serial dilutions and plate counts.
• Data endpoint: Calculate viable counts and log reductions for replicate wells; results inform risk assessment of compatibility.
• Environmental controls: Maintain and document storage temperature (20–25 °C), incubation conditions for recovery media, and validated neutralization procedures.

Practical applications and users

ISO 18259:2014 is used by:

• Contact lens solution and lens-case manufacturers for product development and compatibility testing.
• Microbiology and quality control laboratories performing regulatory and conformity testing.
• R&D teams assessing preservative efficacy in the presence of specific lens materials (hydrogel, silicone hydrogel).
• Regulatory affairs and submission dossiers where compatibility and disinfection claims require robust microbial data.

Benefits:

• Simulates in-use contamination to reveal preservative-lens/case interactions.
• Supports labeling claims for disinfection regimens and storage guidance.
• Provides data to combine with preservative uptake/release studies (ISO 11986) for comprehensive compatibility evaluation.

Related standards

• ISO 14729 - Microbiological requirements and test methods for contact lens care products (Stand‑alone test details, challenge organisms).
• ISO 18369 series - Contact lens vocabulary and measurement methods.
• ISO 11986 - Preservative uptake and release testing (recommended for complementary assessment).

Keywords: ISO 18259:2014, contact lens care products, antimicrobial efficacy, lens case compatibility testing, contact lens disinfection, hydrogel lenses, microbial challenge, ISO testing methods.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 18259
First edition
2014-10-01
Ophthalmic optics — Contact lens care
products — Method to assess contact
lens care products with contact
lenses in a lens case, challenged with
bacterial and fungal organisms
Optique ophtalmique — Produits d’entretien de lentilles de contact
— Méthode d’évaluation des produits d’entretien des lentilles de
contact avec les lentilles de contact dans leur étui, en présence de
contamination par des bactéries et champignons
Reference number
©
ISO 2014
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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ii © ISO 2014 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Rationale . 2
6 Methodology . 2
6.1 General . 2
6.2 Test procedure . 2
7 Performance criteria . 4
Annex A (normative) Preparation of challenge organisms in organic soil . 5
Bibliography . 7
Foreword
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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
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For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 172, Optics and photonics, Subcommittee SC 7,
Ophthalmic optics and instruments.
iv © ISO 2014 – All rights reserved

INTERNATIONAL STANDARD ISO 18259:2014(E)
Ophthalmic optics — Contact lens care products — Method
to assess contact lens care products with contact lenses in
a lens case, challenged with bacterial and fungal organisms
1 Scope
This International Standard specifies an antimicrobial efficacy end point methodology to determine
compatibility of contact lens solutions, lens cases and hydrogel lenses for disinfection. This provides a
process for evaluating compatibility of solutions used for disinfection with contact lenses and lens cases
using an antimicrobial efficacy end point. Specifically, the microbiological effect of the antimicrobial
agent(s) while in the presence of the lens cases and/or lenses will be evaluated as described in the soak
step of the label instructions.
For practical purposes, this does not apply to oxidative systems.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 14729, Ophthalmic optics — Contact lens care products — Microbiological requirements and test
methods for products and regimens for hygienic management of contact lenses
ISO 18369-1, Ophthalmic optics — Contact lenses — Part 1: Vocabulary, classification system and
recommendations for labelling specifications
ISO 18369-3, Ophthalmic optics — Contact lenses — Part 3: Measurement methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 18369-1 apply.
4 Principle
The antimicrobial efficacy of the test solution in combination with a lens and a lens case will be evaluated
at various times following inoculation with organisms in the presence of organic soil. New lenses and
new lens cases shall be used unless otherwise justified. This test will simulate microbial contamination
introduced by patient handling.
5 6
Place a lens in a well of a lens case and inoculate each lens with 1,0 × 10 to 1,0 × 10 cfu; leave inoculum
in contact with the lens for 3 min to 10 min and dispense the appropriate volume (minimum of 2 ml) of
the test solution into each well. The inoculated lenses in solutions will be allowed to soak for various
storage times (the labelled regimen soaking period, at 24 h, at 7 days and at the maximum labelled
storage in the lens case) in order to evaluate the effects of the lens case and the lens on the antimicrobial
activity of the test solution. A separate set of lens case wells shall be prepared for each time point; three
wells shall be evaluated for each unique test condition. Additional time points can be evaluated.
A variety of lenses shall be evaluated, e.g. Group I, Group IV, and Group V. The lens case(s) recommended
for use with the test solution shall be evaluated at a minimum.
All five challenge organisms specified in ISO 14729 shall be used.
Log reductions will be evaluated for all exposure times.
The data generated from this method should be assessed in conjunction with preservative uptake and
release data (ISO 11986).
5 Rationale
These studies are designed to simulate the recommended soaking and storage periods wherein the
contaminating microorganisms are introduced by patient handling.
6 Methodology
6.1 General
Use ISO 14729 for media, challenge organisms, culture maintenance, test equipment, and other details
for conducting the Stand Alone Test with the exception of using lens cases for the microbial challenge.
6.2 Test procedure
6.2.1 Conduct the test using lens types representative of those with which the solution is intended to be
used, e.g. low-water non-ionic lens (Group I), high-water ionic lens (Group IV), and representative silicone
hydrogel lens (Group V). Use −3,00 D lenses. New and unused lenses shall be used unless otherwise
justified.
The lens cases recommended for use with the test solution shall be evaluated at a minimum. The lens cases
used in this test shall be new and unused with no preconditioning unless otherwise justified. Prepare
thr
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