How does increasing water content in a hydrogel lens affect oxygen availability?

How does increasing water content in a hydrogel lens affect oxygen availability?

• A. More oxygen
• B. Variable
• C. No change
• D. Less oxygen

Answer: (A)

Increasing water content in a hydrogel lens boosts how easily oxygen can diffuse through the lens. Oxygen moves from the tear film into the lens and then to the cornea by diffusion, and it dissolves and travels more readily in water-filled spaces than in the polymer itself. So, as the water content rises, the lens’ oxygen permeability increases, allowing more oxygen to reach the cornea. While very high water content can affect other lens properties, the direct effect on oxygen availability is that more water means more oxygen passes through.

Increasing water content in a hydrogel lens boosts how easily oxygen can diffuse through the lens. Oxygen moves from the tear film into the lens and then to the cornea by diffusion, and it dissolves and travels more readily in water-filled spaces than in the polymer itself. So, as the water content rises, the lens’ oxygen permeability increases, allowing more oxygen to reach the cornea. While very high water content can affect other lens properties, the direct effect on oxygen availability is that more water means more oxygen passes through.