1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN ISO 18369-2:2012Ophthalmic optics Contact lensesPart 2: TolerancesBS EN ISO 18369-2:2012 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of
2、EN ISO 18369-2:2012. It supersedes BS EN ISO 18369-2:2006, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee CH/172/9, Contact lenses and contact lens care products.A list of organizations represented on this committee can be obtained on request to its s
3、ecretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012. Published by BSI Standards Limited 2012.ISBN 978 0 580 72699 6 ICS 11.040.70 Compliance with a British Standard
4、 cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2012.Amendments issued since publicationDate T e x t a f f e c t e dEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 18369-2 De
5、cember 2012 ICS 11.040.70 Supersedes EN ISO 18369-2:2006English Version Ophthalmic optics - Contact lenses - Part 2: Tolerances (ISO 18369-2:2012) Optique ophtalmique - Lentilles de contact - Partie 2: Tolrances (ISO 18369-2:2012) Augenoptik - Kontaktlinsen - Teil 2: Grenzabweichungen (ISO 18369-2:2
6、012) This European Standard was approved by CEN on 30 November 2012. 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 bibliographic
7、al 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
8、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, Former Yugoslav Republic of M
9、acedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION
10、EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 18369-2:2012: EBS EN ISO 18369-2:2012EN ISO 18369-2:2012 (E) 3 Foreword This document (EN
11、ISO 18369-2:2012) 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 publicatio
12、n of an identical text or by endorsement, at the latest by June 2013, and conflicting national standards shall be withdrawn at the latest by June 2013. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not b
13、e held responsible for identifying any or all such patent rights. This document supersedes EN ISO 18369-2:2006. According to the CEN/CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria
14、, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey
15、 and the United Kingdom. Endorsement notice The text of ISO 18369-2:2012 has been approved by CEN as a EN ISO 18369-2:2012 without any modification. BS EN ISO 18369-2:2012ISO 18369-2:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standar
16、ds 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 organi
17、zations, 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
18、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
19、 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 18369-2 was prepared by Technical Committee ISO/TC 172, Optics a
20、nd photonics, Subcommittee SC 7, Ophthalmic optics and instruments.This second edition cancels and replaces the first edition (ISO 18369-2:2006), of which Clause 7 and Table 4 have been technically revised.ISO 18369 consists of the following parts, under the general title Ophthalmic optics Contact l
21、enses: 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 ISO 2012 All rights reserved iiiBS EN ISO 18369-2:2012ISO 18369-2:2012(E)IntroductionISO 18369
22、 is applicable 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 are
23、 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 require
24、 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).ISO 18369 is applicable to d
25、etermining allowable tolerances of parameters and properties important for the proper functioning of contact lenses as optical devices. ISO 18369 includes tolerances for single vision contact lenses, bifocal lenses, lenses that alter the flux density and/or spectral composition of transmitted visibl
26、e 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). ISO 18369 covers contact lenses designed with spherical, toric and aspheric surfaces, and recommended methods
27、for the specification of contact lenses.iv ISO 2012 All rights reservedBS EN ISO 18369-2:2012Ophthalmic optics Contact lenses Part 2: Tolerances1 ScopeThis part of ISO 18369 specifies the tolerance limits of the principal optical and physical parameters of rigid, soft and rigid scleral contact lense
28、s.2 Normative referencesThe 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 18369-1, Ophthalmic op
29、tics Contact lenses Part 1: Vocabulary, classification system and recommendations for labelling specificationsISO 18369-3:2006, Ophthalmic optics Contact lenses Part 3: Measurement methodsISO 18369-4:2006, Ophthalmic optics Contact lenses Part 4: Physicochemical properties of contact lens materials3
30、 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 18369-1 apply.4 Tolerances for rigid contact lensesWhen tested as described in ISO 18369-3, the dimensional and optical properties of corneal and scleral rigid contact lenses shall be as specified, within
31、 the appropriate tolerance limits given in Tables 1 and 2. Each dimension and optical property specified shall be determined using a test method with measurement reproducibility better than one-half the tolerance limit specified for the property. For fenestration, truncation and displacement, measur
32、ed values shall not differ from the specified values by more than 10 %.5 Tolerances for soft contact lensesWhen tested as described in ISO 18369-3, the dimensional and optical properties for soft contact lenses shall be as specified, within the appropriate tolerance limits given in Table 3. Each dim
33、ension and optical property specified shall be determined using a test method with measurement reproducibility better than one-half the tolerance limit specified for the property. For truncation and displacement, measured values shall not differ from the specified values by more than 10 %.6 Conditio
34、ning of contact lenses prior to testingContact lenses shall be equilibrated as specified in the relevant test method cited in ISO 18369-3 or as specified by the manufacturer. Lenses made of hydrogel materials shall be equilibrated in the standard saline described in ISO 18369-3 or an equivalent solu
35、tion for the particular method of measurement.INTERNATIONAL STANDARD ISO 18369-2:2012(E) ISO 2012 All rights reserved 1BS EN ISO 18369-2:2012ISO 18369-2:2012(E)7 Oxygen permeability (Dk)Oxygen permeability (Dk) is determined indirectly knowing the oxygen transmissibility (Dk/t) of the material. The
36、tolerance for Dk is 20 % for all types and designs of contact lenses. Test methods for oxygen permeability are specified in ISO 18369-4.8 Transmittance of ultraviolet radiationFor contact lenses claimed to attenuate ultraviolet radiation, total transmittance of ultraviolet radiation through the cont
37、act lens shall conform to those amounts specified in Table 4. Such lenses shall be categorized as “Class 1” or “Class 2” absorbers, according to the measured ultraviolet radiation transmittance.9 Requirements for finish9.1 GeneralAcceptance and failure criteria for inclusions, surface imperfections,
38、 fenestrations (when indicated), edge contour and finish shall be documented by the manufacturer.9.2 Inclusions and surface imperfectionsWhen examined as specified in ISO 18369-3, the contact lens shall not exhibit any inclusions or surface imperfections which could interfere with its intended funct
39、ional use.9.3 FenestrationsThe front and back edges of the holes shall appear finished in the style specified by the manufacturer when examined under 7 magnification.9.4 Edge contour and finishWhen examined under 7 magnification, the contact lens edge shall meet the quality characteristics described
40、 by the manufacturer with respect to shape, smoothness and polish.10 Additional propertiesWhen a manufacturer claims additional contact lens properties (e.g. aspherical design), the properties shall be described by the manufacturer together with appropriate measurement methods and tolerances.2 ISO 2
41、012 All rights reservedBS EN ISO 18369-2:2012ISO 18369-2:2012(E)Table 1 Dimensional tolerances for rigid contact lensesDimensions in millimetresPropertyTolerance limitRelevant methodCorneal contact lensScleral contact lensPMMA Gas permeableBack optic zone radius 0,025 0,05 0,10 ISO 18369-3:2006, 4.1
42、Back optic zone radii of toroidal surfaces a bISO 18369-3:2006, 4.1where 0 0,6 0,075 0,09 0,17Back optic zone diameter c0,20 0,20 0,20 ISO 18369-3:2006, 4.3Back scleral radius (of preformed lens) 0,10 ISO 18369-3:2006, 4.1Basic or primary optic diameter 0,20 ISO 18369-3:2006, 4.3Back or front periph
43、eral radius (where measurable) c0,10 0,10 0,10 ISO 18369-3:2006, 4.1Back peripheral diameter c0,20 0,200,20 (for preformed lenses)ISO 18369-3:2006, 4.3Total diameter b0,10 0,10 0,25 ISO 18369-3:2006, 4.3Front optic zone diameter c0,20 0,20 0,20 ISO 18369-3:2006, 4.3Bifocal segment height 0,10 to +0,
44、20 0,10 to +0,20 0,10 to +0,20 ISO 18369-3:2006, 4.3Centre thickness 0,02 0,02 0,10 ISO 18369-3:2006, 4.4Vertex clearance from cast (for impression scleral lenses) 0,02 ISO 18369-3:2006, 4.1ar is the difference between the radii of the two principal meridians.bThe tolerance applies to each meridian.
45、cThese tolerances apply only to contact lenses with spherical surfaces and distinct curves; they are for a finished contact lens and any blending may make measurement difficult. ISO 2012 All rights reserved 3BS EN ISO 18369-2:2012ISO 18369-2:2012(E)Table 2 Optical tolerances for rigid contact lenses
46、Dimension Tolerance limit Relevant methodBack vertex power in the weaker meridian ISO 18369-3:2006, 4.20 to 5,00 D 0,12 Dover 5,00 D to 10,0 D 0,18 Dover 10,00 D to 15,0 D 0,25 Dover 15,00 D to 20,0 D 0,37 Dover 20,00 D 0,50 DPrismatic error (measured at geometrical centre of the optic zone)Back ver
47、tex power 0 to 6 D 0,25 cm/mBack vertex power over 6 D 0,50 cm/mSpecified prism 0,25 cm/m Optical centration for scleral lenses only (maximum error)0,50 mm ISO 18369-3:2006, 4.3Cylinder power ISO 18369-3:2006, 4.2to 2,00 D 0,25 DISO 18369-3:2006, 4.2 over 2,00 D to 4,00 D 0,37 Dover 4,00 D 0,50 DCyl
48、inder axis 5 ISO 18369-3:2006, 4.2Table 3 Dimensional and optical tolerances for soft contact lensesProperty Tolerance limits Relevant methodBack optic zone radius a b0,20 mm ISO 18369-3:2006, 4.1Sagitta at specified diameter a0,05 mm ISO 18369-3:2006, 4.1Total diameter 0,20 mm ISO 18369-3:2006, 4.3
49、Optic zone diameter 0,20 mm ISO 18369-3:2006, 4.3Centre thickness ctC 0,10 mmtC 0,10 mm0,010 mm + 0,10 tC0,015 mm + 0,05 tCISO 18369-3:2006, 4.4Back vertex power|Fv| 10 D10 D 20 D0,25 D0,50 D1,00 DISO 18369-3:2006, 4.2Prismatic error d|Fv| 6 D|Fv| 6 D0,25 cm/m0,50 cm/mPrescribed optical prism e|Fv| 6 D|Fv| 6 DPrism axis0,25 cm/m0,50 cm/m54 ISO 2012 All rights reservedBS EN ISO 18369-2:2012ISO 18369-2:2012(E)Property Toler
