Oxygen Permeability and Transmissibility

Oxygen transport is different in different CL materials. In conventional hydrogels whether they have low or high water content, oxygen delivery to the ocular surface takes place mainly through the water phase, so the higher the water content, the higher the permeability. 

in these hydrogels EWC and Dk are directly and positively correlated [50, 51]. Conversely, in the Si-Hy materials, oxygen permeation occurs mainly through the silicone-siloxysilane portions of the solid phase in the hydrogel, the contribution of the aqueous phase to gas permeation is very low for the first Si-Hy materials Compan et al. [52] found a slightly higher Dk value for the hydrated Si-Hy materials than for their xerogel (dry state). 

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