New Standard from Last Update.

NATIONAL FOREWORD

This Indian Standard (Part 4) (First Revision) which is identical with ISO 18369-4 : 2017 ‘Ophthalmic optics - Contact lenses - Part 4: Physicochemical properties of contact lens materials’ issued by the International Organization for Standardization was adopted by Bureau of Indian Standards on recommendation of the Ophthalmic Instruments and Appliances Sectional Committee and approval of the Medical Equipment and Hospital Planning Division Council.

This standard was originally published in 1993 as IS 13767 : 1993/ISO 8320 : 1986 ‘Optics and optical instruments - Contact lenses - Vocabulary and symbols’, IS 13903 : 1993 ‘Soft contact lenses - Requirements’ and IS 13928 : 1993 ‘Rigid contact lenses - Requirements’. These were superseded as IS/ISO 18369-4 : 2006 ‘Ophthalmic optics - Contact lenses - Part 4: Physicochemical properties of contact lens materials’. The first revision of this standard has been undertaken to align it with the latest edition of ISO 18369-4 : 2017.

This Indian Standard is published in various parts. The other parts in this series are:

Part 1 Vocabulary, classification system and recommendations for labelling specifications

Part 2 Tolerances

Part 3 Measurement methods

The text of ISO standard may be approved as suitable for publication as Indian Standard without deviations. Certain terminologies and conventions are, however, not identical to those used in the Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker, while in Indian Standards, the current practice is to use a point (.) as the decimal marker.