Which statement correctly describes oxygen availability when water content increases in hydrogel vs silicone-dominated lenses?

Which statement correctly describes oxygen availability when water content increases in hydrogel vs silicone-dominated lenses?

• A. Hydrogel: oxygen increases; SiHy: oxygen decreases
• B. Hydrogel: oxygen decreases; SiHy: oxygen increases
• C. Hydrogel: oxygen increases; SiHy: oxygen increases
• D. Hydrogel: oxygen decreases; SiHy: oxygen decreases

Answer: (A)

Oxygen transport in lenses depends on the dominant diffusion pathway in the material. In hydrogels, oxygen moves mainly through water-filled pores; increasing water content expands these diffusion routes and raises how much oxygen can reach the cornea. In silicone-dominated lenses, the diffusion path is the silicone network, which provides high permeability, but adding more water reduces the relative amount of silicone and can disrupt those continuous pathways, lowering overall oxygen transport. So, as water content increases, oxygen availability goes up for hydrogel lenses but tends to go down for silicone-dominated lenses.

Oxygen transport in lenses depends on the dominant diffusion pathway in the material. In hydrogels, oxygen moves mainly through water-filled pores; increasing water content expands these diffusion routes and raises how much oxygen can reach the cornea. In silicone-dominated lenses, the diffusion path is the silicone network, which provides high permeability, but adding more water reduces the relative amount of silicone and can disrupt those continuous pathways, lowering overall oxygen transport. So, as water content increases, oxygen availability goes up for hydrogel lenses but tends to go down for silicone-dominated lenses.