What characteristic do higher Dk materials provide compared to lower Dk materials for contact lenses?

Higher Dk materials are designed to allow significantly more oxygen to pass through the contact lens to the cornea, which is vital for maintaining corneal health and comfort during lens wear. Dk, or diffusivity and permeability of oxygen, is a measure of how easily oxygen can diffuse through a lens material. Therefore, lenses with a higher Dk value facilitate better oxygen transmission. This is particularly important for extended wear lenses, where the cornea still needs adequate oxygen supply even when the eyelid is closed, such as during sleep.

In comparison, lower Dk materials limit the amount of oxygen available to the cornea, potentially leading to complications such as corneal hypoxia, discomfort, or even long-term damage to the corneal tissue. Thus, the enhanced oxygen permeability provided by higher Dk materials helps support eye health, reduces the risk of complications, and can contribute to overall better comfort during wear.