The Dk project: an interlaboratory comparison of Dk/L measurements |
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| Authors: | B A Holden J Newton-Howes L Winterton I Fatt H Hamano D La Hood N A Brennan N Efron |
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| Institution: | Cornea and Contact Lens Research Unit, School of Optometry, University of New South Wales, Australia. |
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| Abstract: | The oxygen transmissibilities (Dk/L) of a set of 48 contact lenses made from 8 different materials were measured by 4 laboratories. The L/Dk measurements from each laboratory were compared and correlated. Samples which were not masked with a fixed front surface aperture during measurement were corrected for edge effects. This paper shows that provided L/Dk is calculated for each lens using the same technique and Dk is derived using a graphical method of calculation, similar results can be obtained by all laboratories. However, the agreement was less good for materials of Dk greater than 70 x 10(-11) (cm2/s) (ml O2/ml x mm Hg). |
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