Podcast
Questions and Answers
What is the DK/e value provided for a -3.00D lens?
At 35°C
Which method uses a Clark electrode to detect oxygen transmission?
Different manufacturers use the same methods for measuring lens oxygen permeability.
False
At what temperature should the measurements of lens optical density be taken?
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The higher the Dk, the higher the permeability to ___
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What is the maximum percentage of oxygen in breathable air?
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What is the Dk/e classification range for 'Faible (Low)'?
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What two factors contribute to the calculation of Dk/e?
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Match the following Dk/e values with their equivalent oxygen percentage (EOP):
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Study Notes
Permeabiliy and Transmissibility of Lenses
- By convention, manufacturers specify DK/e at 35°C
- Lens power increases closer to the centre
- Lens power decreases as you move towards the edge
- Measurements for different len types varies, making direct comparisons difficult
- Comparing data from different methods/specifications in technical documents is sometimes tricky
- Measurements are dependent on experimental conditions like temperature, pressure and concentration, so these factors should be considered when comparing
- Current measurements for materials SI-HI are only slightly reliable
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Description
Test your knowledge on contact lens oxygen permeability and the Dk/e value. This quiz covers essential concepts such as measurement methods, temperature conditions, and factors influencing Dk/e classification for lenses. Ideal for optics students and professionals alike.
