ISO 11539 pdf download

ISO 11539 pdf download.Ophthalmic optics — Contact lenses — Classification of contact lenses and contact lens materials 1 Scope This International Standard describes a method for classifying contact lenses and the materials used for their manufacture. It permits the specific and non-proprietary identification, in simplified form, of the major chemical components of the material. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 8320-1 , Contact lenses and contact lens care products — Vocabulary — Part 1 : Contact lenses. ISO 991 3-1 , Optics and optical instruments — Contact lenses — Part 1 : Determination of oxygen permeability and transmissibility with the FATT method. ISO 991 3-2, Optics and optical instruments — Contact lenses — Part 2: Determination of oxygen permeability and transmissibility by the coulometric method. ISO 1 0339, Ophthalmic optics — Contact lenses — Determination of water content of hydrogel lenses. 3 Terms and definitions For the purposes of this International Standard, the terms and definitions given in ISO 8320-1 apply. 4 Method of classification 4.1 General The specific classification of a contact lens or contact lens material is given as a six-part code as follows: (prefix) (stem) (series suffix) (group suffix) (Dk range) (modification code) For hydrogel contact lens materials, the classification denotes whether the material is ionic and the range in which the water content of the material lies. For non-hydrogel contact lens materials, the classification indicates the presence/absence of silicon/fluorine and the oxygen permeability grouping. For both types of material, the presence or absence of surface modifications is noted (see 4.7).4.2 Prefix The prefix is a term assigned to a material to designate a specific chemical formulation. Use of this prefix, which is administered by the United States Adopted Names (USAN) Council 1 ) , is optional for all countries other than the United States of America. 4.3 Stem Two types of stem are used. The filcon stem is affixed to the prefix...