Which material is associated with higher oxygen permeability among PMMA, S/A, F-S/A?

Which material is associated with higher oxygen permeability among PMMA, S/A, F-S/A?

• A. Fluoro-silicone/acrylate
• B. PMMA
• C. Silicone/acrylate
• D. Hydrogel

Answer: (A)

Oxygen permeability in contact lens materials is determined by how easily oxygen dissolves in the polymer and diffuses through it. Silicone-containing polymers enable much higher gas diffusion than non-silicone ones, which is why they’re favored for high Dk lenses. Fluoro-silicone/acrylate combines a silicone network with fluorinated groups, increasing the free volume and maintaining good mechanical properties, so it typically achieves the highest permeability among common options. PMMA is rigid and non-silicone, giving very low oxygen permeability. A silicone/acrylate blend is high in permeability due to the silicone content, but usually not as high as the fluoro-silicone/acrylate. Hydrogels rely on water content for oxygen transport; while they can be permeable, their Dk values are generally lower than those of silicone-based materials in typical comparisons.

Oxygen permeability in contact lens materials is determined by how easily oxygen dissolves in the polymer and diffuses through it. Silicone-containing polymers enable much higher gas diffusion than non-silicone ones, which is why they’re favored for high Dk lenses. Fluoro-silicone/acrylate combines a silicone network with fluorinated groups, increasing the free volume and maintaining good mechanical properties, so it typically achieves the highest permeability among common options. PMMA is rigid and non-silicone, giving very low oxygen permeability. A silicone/acrylate blend is high in permeability due to the silicone content, but usually not as high as the fluoro-silicone/acrylate. Hydrogels rely on water content for oxygen transport; while they can be permeable, their Dk values are generally lower than those of silicone-based materials in typical comparisons.