Oxygen permeability is inherent to the material.

• A. True
• B. False
• C. It depends on thickness
• D. Only for silicone hydrogels

Answer: (B)

Oxygen permeability refers to how easily oxygen can diffuse through a material, which is captured by the intrinsic property Dk. However, the practical amount of oxygen that actually reaches the cornea through a lens depends on how thick the lens is. This is because the rate of oxygen delivery is influenced by the thickness, described clinically by oxygen transmissibility (Dk/t). So while the material’s permeability (Dk) is inherent, the overall oxygen supply to the eye changes with lens thickness. That’s why the statement is not strictly true.