What is the water content of a SiHy lens?

• A. high, >60%
• B. low, <50%
• C. medium, 40-60%
• D. very high, >70%

Answer: (B)

SiHy lenses deliver oxygen primarily through the silicone component, not through a high water content. Keeping the water content relatively low helps balance durability, surface wettability, and dehydration resistance while still providing good oxygen transmission. That’s why the typical water content is under 50%, rather than high or very high. In practice, many SiHy lenses sit in roughly the mid-30s to mid-40s percent water content, with values sometimes approaching but not exceeding 50%.