ISO INTERNATIONAL STANDARD 18369-3 Second edition 2017-08 Ophthalmic optics Contact lenses Part 3: Measurement methods Optique ophtalmique -Lentilles de contact - Partie 3: Meéthodes de mesure Reference number ISO 18369-3:2017(E) so International Organization for Standardization @ IS0 2017 vided by IHS under ted without license from IHS IS0 18369-3:2017(E) COPYRIGHTPROTECTEDDOCUMENT IS0 2017, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISOcopyrightoffice Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org Internatinair PrganizationforStandardization @ IS0 2017 - All rights reserved etworking permitted without license from IHS IS0 18369-3:2017(E) Contents Page Foreword ..iv 1 Scope 2 Normative references 3 Terms and definitions 4 Methods of measurement for contact lenses 4.1 General .1 4.2 Radius of curvature. 4.2.1 General .2 4.2.2 Optical spherometry (rigid contact lenses) .3 4.2.3 Sagittal height method. .6 4.3 Label back vertex power. .11 4.3.1 General. .11 4.3.2 Focimeter specification .11 4.3.3 Calibration.. .12 4.3.4 Focimeter measurement of rigid lenses .13 4.3.5 Focimeter measurement of hydrogel lenses ..13 4.3.6 Measurement of hydrogel contact lenses by immersion in saline ..13 4.3.7 Addition power measurement. .14 4.4 Diameters and widths .14 4.4.1 Total diameter. .14 4.4.2 Zone diameters and widths 19 4.5 Thickness. 20 4.5.1 General. 20 4.5.2 Dial gauge method 20 4.5.3 Low-force mechanical gauge method 21 4.6 Edge inspection .22 4.7 Determination of inclusions and surface imperfections 22 4.8 Spectral transmittance 23 4.8.1 General. 23 4.8.2 Instrument specification, test conditions and procedure .23 4.9 Saline solution for testing .24 4.9.1 General 24 4.9.2 Formulation 24 4.9.3 Preparation procedure .25 4.9.4 Packaging and labelling .25 5 Test report. .26 Annex A (informative) Measurement of rigid contact lens curvature using interferometry .27 Annex B (informative) Measurement of label back vertex power of soft contact lenses immersed in saline using the Moiré deflectometer or Hartmann methods ..29 Annex C (informative) Measurement of the radius of curvature of contact lenses using the ophthalmometer .33 Annex D (informative) Paddle support for focimeters used for power measurements of contactlenses .38 Bibliography .40 iii cense with ISt ed without license from IHS