1、BRITISH STANDARDBS EN ISO 18369-4:2006Ophthalmic optics Contact lenses Part 4: Physicochemical properties of contact lens materialsThe European Standard EN ISO 18369-4:2006 has the status of a British StandardICS 11.040.70g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g
2、44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 18369-4:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 September 2006 BSI 2006ISBN 0 580 48488 2Nation
3、al forewordThis British Standard was published by BSI. It is the UK implementation of EN ISO 18369-4:2006. It supersedes BS EN ISO 10339:1999, BS EN ISO 10340:1997, BS EN ISO 11984:2000, BS EN ISO 9913-1:1998, BS EN ISO 9913-2:2000 and BS EN ISO 9914:1997, which are withdrawn.The UK participation in
4、 its preparation was entrusted by Technical Committee CH/172, Ophthalmic optics, to Subcommittee CH/172/9, Contact lenses and contact lens care products.A list of organizations represented on CH/172/9 can be obtained on request to its secretary.This publication does not purport to include all the ne
5、cessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 18369-4August 2006ICS 1
6、1.040.70 Supersedes EN ISO 10339:1999, EN ISO 10340:1996,EN ISO 11984:1999, EN ISO 9913-1:1998, EN ISO 9913-2:2000, EN ISO 9914:1996 English VersionOphthalmic optics - Contact lenses - Part 4: Physicochemicalproperties of contact lens materials (ISO 18369-4:2006)Optique ophtalmique - Lentilles de co
7、ntact - Partie 4:Proprits physicochimiques des matriaux des lentilles decontact (ISO 18369-4:2006)Augenoptik - Kontaktlinsen - Teil 4: Physikalisch-chemische Eigenschaften von Kontaktlinsenmaterialien(ISO 18369-4:2006)This European Standard was approved by CEN on 24 May 2006.CEN members are bound to
8、 comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central
9、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 translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the of
10、ficialversions.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, Spai
11、n, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Membe
12、rs.Ref. No. EN ISO 18369-4:2006: EForeword This European Standard shall be given the status of a national standard, either by publication of an identical at the latest by February 2007. This document supersedes EN ISO 10339:1999, EN ISO 10340:1996, EN ISO 11984:1999, According to the CEN/CENELEC Int
13、ernal 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, Neth
14、erlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Endorsement notice The text of ISO 18369-4:2006 has been approved by CEN as EN ISO 18369-4:2006 without any modifications. This document (EN ISO 18369-4:2006) has been prepared by Technical
15、 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. text or by endorsement, at the latest by February 2007, and conflicting national standards shall be withdrawn EN ISO 9913-1:1998,
16、EN ISO 9913-2:2000, EN ISO 9914:1996. EN ISO 18369-4:2006Reference numberISO 18369-4:2006(E)INTERNATIONAL STANDARD ISO18369-4First edition2006-08-15Ophthalmic optics Contact lenses Part 4: Physicochemical properties of contact lens materials Optique ophtalmique Lentilles de contact Partie 4: Proprit
17、s physicochimiques des matriaux des lentilles de contact EN ISO 18369-4:2006ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Physicochemical properties of contact lenses . 1 4.1 Repeatability, test methods and units of measure 1 4.2 E
18、xtractables. 2 4.3 Rigid lens flexural deformation and rupture 5 4.4 Oxygen permeability. 8 4.5 Refractive index 24 4.6 Water content 26 5 Test report . 29 Bibliography . 30 EN ISO 18369-4:2006iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national
19、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
20、 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 g
21、iven 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 leas
22、t 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 18369-4 was prepared by Technical Committee ISO/TC 17
23、2, Optics and photonics, Subcommittee SC 7, Ophthalmic optics and instruments. This first edition cancels and replaces ISO 9913-1:1996, ISO 9913-2:2000, ISO 9914:1995, ISO 10339:1997, ISO 10340:1995 and ISO 11984:1999, which have been technically revised. ISO 18369 consists of the following parts, u
24、nder the general title Ophthalmic optics Contact lenses: Part 1: Vocabulary, classification system and recommendations for labelling specifications Part 2: Tolerances Part 3: Measurement methods Part 4: Physicochemical properties of contact lens materials EN ISO 18369-4:2006vIntroduction The ISO 183
25、69 series applies to contact lenses, which are devices worn over the front surface of the eye in contact with the preocular tear film. This part of ISO 18369 covers rigid (hard) corneal and scleral contact lenses, as well as soft contact lenses. Rigid lenses maintain their own shape unsupported and
26、are made of transparent optical-grade plastics, such as polymethylmethacrylate (PMMA), cellulose acetate butyrate (CAB), polyacrylate/siloxane copolymers, rigid polysiloxanes (silicone resins), butylstyrenes, fluoropolymers, and fluorosiloxanes, etc. Soft contact lenses are easily deformable and req
27、uire support for proper shape. A very large subset of soft contact lenses consists of transparent hydrogels containing water in concentrations greater than 10 %. Soft contact lenses can also be made of non-hydrogel materials, e.g. flexible polysiloxanes (silicone elastomers). The ISO 18369 series is
28、 applicable to determining allowable tolerances of parameters and properties important for proper functioning of contact lenses as optical devices. The ISO 18369 includes tolerances for single vision contact lenses, bifocal lenses, lenses that alter the flux density and/or spectral composition of tr
29、ansmitted visible light (tinted or pigmented contact lenses, such as those with enhancing, handling, and/or opaque tints), and lenses that significantly attenuate ultraviolet radiation (UV-absorbing lenses). The ISO 18369 series of standards covers contact lenses designed with spherical, toric, and
30、aspheric surfaces, and recommended methods for the specification of contact lenses. EN ISO 18369-4:2006blank1Ophthalmic optics Contact lenses Part 4: Physicochemical properties of contact lens materials 1 Scope This part of ISO 18369 specifies the methods of testing the physicochemical properties of
31、 contact lens materials. These are extraction, rigid lens flexure and breakage, oxygen permeability, refractive index and water content. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited appl
32、ies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 3696:1987, Water for analytical laboratory use Specification and test methods ISO 18369-1:2006, Ophthalmic optics Contact lenses Part 1: Vocabulary, classification system and recommenda
33、tions for labelling specifications ISO 18369-3:2006, 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 Physicochemical properties of contact lenses 4.1 Repeatability, test me
34、thods and units of measure The physicochemical properties or conditions listed in Table 1 are measurable characteristics of hydrogel and nonhydrogel materials that have been successfully manufactured into contact lenses. In addition, Table 1 includes repeatability, test methods, and units of measure
35、 for these characteristics. If alternative methods are used, they should be so stipulated. EN ISO 18369-4:20062 Table 1 Physiochemical properties: Repeatability, test methods and units of measure Property Repeatability Units of measure Test method Extractables b Mass % 4.2 Flexural deformation bg 4.
36、3 Oxygen permeability 10 % Dk unitsa4.4 Refractive index 0,01 dimensionless 4.5 Water content 2 % absolute % 4.6 aDk is reported in units of 1011(cm2/ s) ml O2/(ml hPa) and called “Dk units”. bRepeatability of these test results shall be established in individual laboratories according to the terms
37、and definitions given in ISO 18369-1. 4.2 Extractables 4.2.1 General Soxhlet extraction with different solvents is a standard method for quantitative determination of substances extractable from contact lenses. The contact lenses are dried to constant mass and the difference between the original dry
38、 mass of the lenses and the extracted dry mass determines the quantity of extractable substances (extractables). Knowledge of the quantity and identity of extractable substances is helpful in evaluating new contact lens materials and in determining the subsequent pre-clinical examination programme.
39、The material extracted from the contact lenses may be examined by appropriate chromatographic, spectrophotometric, and wet analytical methods to identify residual monomers, cross-linking agents, catalysts, etc. that were employed in the polymerization process. 4.2.2 Principle This method uses a norm
40、al Soxhlet extraction apparatus. Water and at least one suitable organic solvent are used for extraction. In selecting the organic solvent(s) to be used, consideration should be given to the effect of the solvent upon the matrix of the material. Ideally, a solvent should not swell or degrade the con
41、tact lens material. However, in the development of new contact lens materials, a solvent that causes reversible swelling may give valuable information relating to the possibility for extraction over extended periods of time. 4.2.3 Apparatus A standard borosilicate glass Soxhlet extraction apparatus
42、(see Figure 1) consisting of the Soxhlet extractor (30 ml suggested), condenser, round bottom flask (100 ml suggested), and a heating mantle shall be used. A perforated stainless steel, sintered glass, paper or equivalent extraction thimble fitted with a glass wool plug or other suitable closure sha
43、ll be used. A vacuum oven or equivalent drying apparatus and an analytical balance capable of weighing to 0,1 mg are required. 4.2.4 Reagents Distilled or deionized water complying with Grade 3 of ISO 3696:1987 shall be used. The appropriate organic solvent (see Table 2) should be analytical grade o
44、r better. Laboratory-grade boiling stones or anti-bumping granules are required along with a suitable active desiccant. Selection of the desiccant will depend upon the characteristics of the test material. EN ISO 18369-4:20063Figure 1 Extraction apparatus Table 2 Guide to the selection of solvents f
45、or use in extraction of contact lenses Material Solvent Corresponds toWater (distilled or deionized) Mild extraction (simulates in-eye extraction) n-Hexane Mild extraction (non-polar solvent) Ethanol or methanol Extraction of majority of uncrosslinked material (but swells and may degrade material) H
46、ydrogels Dichloromethane or chloroform Extraction of all uncrosslinked material (but swells and is likely to degrade material) Water (distilled or deionized) Mild extraction (simulates in-eye extraction) n-Hexane Mild extraction (non-polar solvent) Hard and RGP and silicone elastomers Dichloromethan
47、e or chloroform Extraction of all uncrosslinked material (but swells and is likely to degrade material) EN ISO 18369-4:20064 4.2.5 Test samples Test samples shall be representative of the finished product and be in finished contact lens form. The method of preparing and finishing the lenses shall re
48、flect as far as possible the normal production processes including sterilization. A sufficient number of lenses shall be used so that the total dry mass before extraction shall be no less than 200 mg. Hydrophilic lenses are usually packaged in a solution containing inorganic salts. When using water
49、as the extracting solution, an adjustment in the calculation should be made for the contribution of the inorganic salt of the packaging solution. The water content of the lenses will be required in order to accurately calculate the contribution of the inorganic salt to the extractables. Alternatively, the lenses may be equilibrated in at least two changes of water each for 24 h at room temperature prior to beginning the test. 4.2.6 Test procedure Dry the lenses, preferably under vacuum, at 60 C 5 C to constant mass. Then allow the
