What impact does a higher Dk value have on a contact lens?

What impact does a higher Dk value have on a contact lens?

• A. Reduces corneal dryness
• B. Increases lens stiffness
• C. Thickens the lens
• D. Decreases lens transparency

Answer: (A)

A higher Dk value in a contact lens refers to the permeability of the lens material to oxygen. Dk stands for the product of the diffusion coefficient (D) and the solubility coefficient (k) of oxygen in the lens material. When the Dk value is higher, it allows more oxygen to pass through the lens to the cornea. This increased oxygen transmission is crucial for maintaining corneal health, as the cornea relies on oxygen to stay hydrated and clear. Reducing corneal dryness is significant because a well-hydrated cornea is less prone to irritation and discomfort. Adequate oxygen supply also prevents hypoxia-related complications, which can manifest as redness, swelling, or a feeling of dryness in the eyes. Therefore, a higher Dk value contributes positively to the overall comfort of the contact lens wear, promoting better ocular health and reducing the sensation of dryness during lens wear. In contrast, options related to lens stiffness, thickness, or transparency don't directly correlate with a higher Dk value. A higher Dk does not inherently make a lens stiffer or thicker, nor does it affect its transparency negatively; these factors are determined more by the lens design and material properties unrelated to oxygen permeability.

A higher Dk value in a contact lens refers to the permeability of the lens material to oxygen. Dk stands for the product of the diffusion coefficient (D) and the solubility coefficient (k) of oxygen in the lens material. When the Dk value is higher, it allows more oxygen to pass through the lens to the cornea. This increased oxygen transmission is crucial for maintaining corneal health, as the cornea relies on oxygen to stay hydrated and clear.

Reducing corneal dryness is significant because a well-hydrated cornea is less prone to irritation and discomfort. Adequate oxygen supply also prevents hypoxia-related complications, which can manifest as redness, swelling, or a feeling of dryness in the eyes. Therefore, a higher Dk value contributes positively to the overall comfort of the contact lens wear, promoting better ocular health and reducing the sensation of dryness during lens wear.

In contrast, options related to lens stiffness, thickness, or transparency don't directly correlate with a higher Dk value. A higher Dk does not inherently make a lens stiffer or thicker, nor does it affect its transparency negatively; these factors are determined more by the lens design and material properties unrelated to oxygen permeability.